2022, 23(6):1549-1571. DOI: 10.13430/j.cnki.jpgr.20220423002
Abstract:With the increasing demand of nutritional function of colored wheat, the genetic research of colored wheat becomes more and more thorough, and there are more and more varieties of colored wheat. However, the germplasm resources of colored wheat in China remain unclear. In order to meet the rapid demand in the area of the colored nutrition wheat genetics and breeding, this paper summarized research advance on gene discovery and germplasm resources breeding utilization of the colored wheat. We introduced the colored wheat gene originated from germplasm resources, followed by introduction of chromosomes complement and pedigree of colored wheat, as well as comprehensive summary on colored wheat breeding and germplasm innovation in China. Sixty colored wheat varieties were approved in China in the past 24 years, including 49 purple (black) grain varieties, 10 blue grain varieties and 1 green grain variety. In addition, 23 new colored wheat germplasm resources were developed. Especially for the past four years, many colored wheat varieties have been approved. Henan province, Shandong province, Hebei province and Shanxi province was the four larger colored wheat breeding and industrialization bases. Most of the colored wheat varieties were from the hybridization between colored wheat and common wheat, and a larger proportion of the genes in colored wheat were from the distant hybridization between wheat and T.boeoticum, wild emmer wheat, Agropyron species, rye, Leymus, etc. Forty-seven colored wheat varieties showed grain protein content over 14%, four colored wheat varieties with grain protein content over 18%, and four colored wheat varieties with dough stable time over 10 min. Considering the problems of colored wheat genetic breeding and industrialization, we would like to suggest that the protection and utilization of crop germplasm resources should follow the basic principle of "if there is difference, it should be selected; if it can be inherited, it should be directed; if it has valuable, it should be conserved; it should be identified, must to be accurate; foster it strengths, use it widely". Collectively, this review will provide useful information and gene germplasm resources for the research of colored wheat genetics and breeding in China, and promote the in-depth development of colored wheat genetics and breeding research in China.
2022, 23(6):1572-1584. DOI: 10.13430/j.cnki.jpgr.20220321004
Abstract:Hidden hunger caused by imbalanced human diet and lack of micronutrients has been paid increasing attention. One solution in achieving biofortification and functional food is to breed excellent crop varieties rich with various micronutrients by deployment of biological breeding technologies. A large number of studies have shown enrichment of anthocyanin, iron, zinc, selenium, trace nutrients and vitamins, folic acid, protein in color wheat germplasm resources. These components have certain effect for treatment of inflammation, cancer, diabetes, cardiovascular disease, anemia, and poor growth and development, etc, thus showing an important role in ensuring food security and human health. In this paper, we first introduce the background information of hidden hunger, biofortification, functional food, functional agriculture and functional varieties, followed by a highlighted summarization on the research progress of functional nutrition components and genetic breeding of colored wheat germplasm resources. We suggest to collect and create new color functional nutrition wheat germplasm, explore genes with excellent nutritional components, reveal the genetic coupling mechanism among anthocyanins and micronutritions (trace elements such as selenium, zinc and chromium, vitamins, 8 amino acids that cannot be synthesized by human body), in order to provide theoretical basis and technical support for color wheat biofortification and main grain functionalization.
2022, 23(6):1585-1593. DOI: 10.13430/j.cnki.jpgr.20220518003
Abstract:Salt stress is one of the most important abiotic stresses, which seriously threatens the growth and development of plants. Understanding the adaptive mechanisms of plant to salt stress is beneficial for the breeding of salt tolerant crops and the effective use of saline land to meet the increasing demand of food supply. Salt stress causes ion imbalance, osmotic derangement, and accumulation of toxic substances, especially reactive oxygen species (ROS), in plants. To adapt to salt stress, the plants have to balance cellular ions, remodel osmotic potential and maintain ROS. The former researches on the genetic, physiological and biochemical subjects have revealed a large number of plant regulators responding salt stresses, which might modulate plant salt tolerance through multiple and complex stress signal pathways. This paper reviews the salt sensing, signal transduction, gene expression regulation, phytohormone regulation and adaptive response of plants under salt stress, and provides a relatively complete summary of plant salt stress response mechanisms.
2022, 23(6):1594-1603. DOI: 10.13430/j.cnki.jpgr.20220411002
Abstract:Salt stress is one of the main environmental factors that result in the stunted growth and yield losses in mungbean. Understanding of the tolerance mechanism under salt stress conditions and breeding for salt-tolerant mungbean cultivars would become of interest to increase the use ratio of saline-alkali land. This review summaries the identification methods and evaluation indexes of mungbean salt tolerance, the identification of salt-tolerant germplasms, the discovery of salt-tolerant genes, and the strategies to improve salt tolerance. Moreover, we propose future research focuses and experimental strategies, which aims to provide a reference for future research and breeding highly salt-tolerant mungbean varieties with elite agronomic traits.
2022, 23(6):1604-1612. DOI: 10.13430/j.cnki.jpgr.20220426003
Abstract:The establishment of Adaxial-Abaxial polarity of plant leaves is one of the important processes in leaf morphogenesis. ASYMMETRIC LEAVES1/ASYMMETRIC LEAVES2 (AS1/AS2) are key transcription factors that modulate the Adaxial-Abaxial polarity in plant leaf development. These factors are able to cooperate with multiple proteins or miRNAs in the direct or indirect manners, in order to coordinate the development and formation of plant leaves. This review summarized the conserved structural features of AS1/AS2 and their regulatory functions involved in leaf development and morphogenesis, which might provide insights for further deciphering the molecular mechanisms of AS1/AS2.
2022, 23(6):1613-1625. DOI: 10.13430/j.cnki.jpgr.20220417001
Abstract:The diversity analysis and comprehensive evaluation of 22 fruit traits of 116 jujube germplasms were conducted by deployment of the coefficient of variation, genetic diversity index, cluster analysis, principal component analysis and comprehensive score. The coefficient of variation at 13 quantitative traits ranged from 1.76% to 41.30 %, and a higher coefficient of variability were detected at two traits single fruit weight and content of titratable acid. Shannon-Weaver Information index of 22 fruit traits ranged from 1.04 to 2.05, while a higher H' index was observed at the fruit diameter (2.05), vitamin C content (2.04), fruit shape (1.88) and fruit color (1.10). The cluster analysis using the phenotypic datasets at the 22 fruit traits suggested four groups, including Group I that belonged to wild resource type, group II that belonged to high nutrient content germplasm type, group III that belonged to specific nutrient content germplasm, and group IV that belonged to germplasm type with good fruit appearance quality. The 22 fruit traits were divided into 8 principal components by principal component analysis, and the cumulative contribution rate was 75.620%. The first principal component was associated with fruit size, the second principal component was associated with fruit shape index, and the third and fourth principal components were associated with fruit nutrients and fruit taste. The comprehensive score (D) of fruit traits ranged from 0.15 to 1.04, with an average value of 0.64. The comprehensive evaluation suggested the elite germplasms ‘zanjing’ of Hebei Province and ‘yangjiashandazao’ of Linxian county of Shanxi Province. Based on the performance at fruit traits, 14 germplasms including ‘sihongdazao’, ‘zanhuang1’, ‘qingxumoguzao’, ‘yucinaitouzao’, ‘xiangfenhuluzao’, ‘luzao7’, ‘jishanshuizao’, ‘jishanhamazao’, ‘jishanzhuyazao’, ‘linxiantiansuanzao’, ‘linxianliujiahuizao’, ‘xingxianlaopozao’, ‘linxiankaiyangdasuanzao’ and ‘luzao10’, were identified. Collectively, the diversity analysis and identification of elite germplasm would provide important reference for the innovation and utilization of jujube germplasm resources and the construction of comprehensive evaluation system.
2022, 23(6):1626-1635. DOI: 10.13430/j.cnki.jpgr.20220407005
Abstract:Drought is the most serious abiotic stress in rice, and improving its drought resistance via enhancing water uptake capability from deep soil is one of the main objectives in the breeding program. In this study, 2234 cultivated rice germplasm resources from China and abroad were evaluated for drought avoidance using the ratio of deep rooting (RDR) as the index. 131 germplasm with different RDR were evaluated for drought resistance at the reproductive stage. The mean RDR of tested genotypes is 25.8%, ranging from 8.6% to 60.1%. In 25.2% of tested genotypes the RDR was less 20%, and in 47.2% of tested genotypes a RDR was between 20% and 30%, only 6.1% of tested genotypes a RDR was more than 40%. Exotic germplasm collected from abroad, as well as the genotypes from Shanghai, Hunan, and Jiangsu provinces of China were observed with a higher RDR. Less than 1% of the germplasm from Guangdong, Guizhou and Guangxi provinces of China had a RDR over 40%. In general, the landrace germplasm population showed a higher RDR than that of the improved cultivars (lines). In japonica and indica germplasm, 13.2% and 3.7% of tested genotypes, respectively, were observed with a RDR over 40%. There are 33 high RDR geremplasm from Hunan province while one high RDR indica germplasm from Guangdong, Guangxi, and Guizhou, respectively. Considering the spikelet fertility under drought and water conditions, as well as the relative spikelets per panicle and relative spikelet fertility, 26 genotypes showing strong drought resistance were identified, which are good donors for rice drought resistance breeding and gene mining.
2022, 23(6):1636-1643. DOI: 10.13430/j.cnki.jpgr.20220419004
Abstract:Maize stalk lodging seriously affects yield, quality and mechanized harvest. In this study, 110 maize germplasm resources with rich genetic diversity were used to analyze the correlation among 8 traits of stalk strength, vascular bundle and fiber content, and the differences of consanguinity germplasm were compared. The results show that there is a synergistic effect between bending strength and puncture strength, the number of large vascular bundles and the number of small vascular bundles, neutral detergent fiber and acid detergent fiber, neutral detergent fiber and hemicellulose. Four traits, including the number of large vascular bundles, the content of neutral detergent fiber, the bending strength and the puncture strength, all positively correlated with the lodging resistance. Under climatic conditions in Nanning, Guangxi, the tropical maize germplasms showed stronger stalk strength, more vascular bundles and higher fiber content, in which elite germplasms with strong lodging resistance were identified. Collectively, these results provided theoretical reference for deciphering the lodging resistance of maize, which has implication for the improvement and utilization of tropical maize germplasms.
2022, 23(6):1644-1659. DOI: 10.13430/j.cnki.jpgr.20220407004
Abstract:This study attempted to investigate the phenotypic variation at nine plant architecture related traits (including plant height, stem diameter, and leaf related traits), via accurate identification and comprehensive evaluation of 371 domestic sorghum accessions, followed by the coefficient of variation, correlation analysis, cluster analysis, principal component analysis, and affiliation function F-value evaluation methods. Based on the phenotypic datasets from two years at two locations, the mean coefficient of variation ranged from 10.14% to 35.70%, and the genetic diversity index ranged from 1.94 to 2.14. These results revealed rich phenotypic variations in the germplasm collection, and visible variations for particular traits including internode number, the leaf angle of the second and third leaf from top, and stem diameter under environmental conditions. Based on cluster analysis, sorghum accessions were divided into three groups: Group I was medium-culm spreading and medium-culm compact plants, Group II was tall-culm spreading plants and Group III was short-culm compact plants. The nine traits were divided into four principal components by principal component analysis. The first principal component was mainly the straight stem, the leaf width of the second and third leaves from the top, and the number of internodes, with a contribution of 36.424%. The fourth principle component consisted mainly of the angle of the second leaf from the top, with a contribution of 11.132%. Stepwise regression analysis identified plant height, internode number, stem diameter, and the leaf angle of the second leaf from the top as the main traits that could be used for plant type analysis. Thirty elite germplasm resources, including ‘103’, ‘Beijing Selection No.1’, ‘44F’, and ‘714R’, were selected using the integrated evaluation method of the affiliation function in combination with breeding objectives. Through the comparison of traits between different sorghum variety categories, it is found that the improved varieties have a clear trend towards dwarfism, compactness, and resistance to overturning, which are more suitable for modern production requirements.
2022, 23(6):1660-1669. DOI: 10.13430/j.cnki.jpgr.20220418003
Abstract:Fusarium wilt is one of the most serious diseases causing the yield loss in Mungbean. Identification of resistant resources at the seedling stage and breeding for resistant Mungbean varieties become of importance. In this study, 215 Mungbean core germplasm resources and 85 new breeding lines were tested for resistance against fusarium wilt at the seedling stage. The differences in resistance to fusarium wilt were observed among germplasm resources collected from different geographical regions. For these germplasm resources that were collected from different regions of China, ca. 50% of germplasm resources in Northeast, East and Central China turned to be resistant, while 40.4% of genotypes in North China were resistant. If compared with those of other regions, a higher disease resistance was observed in germplasm collected from Northwest, Southwest and South China. 40.0% of the exotic germplasm were found to be resistant. Eighteen accessions showing high resistance (HR) to fusarium wilt were found at the seedling stage, and of them several had been used to generate RIL populations. Six breeding lines showing high resistant and excellent agronomic performance in lifecycle were obtained. Collectively, this study provided excellent resources and theoretical basis in breeding of new mungbean varieties resistant to fusarium wilt and future decoding of resistance genes.
2022, 23(6):1670-1681. DOI: 10.13430/j.cnki.jpgr.20220427001
Abstract:To clarify the genetic diversity of Actinidia Lindl. germplasm resources in Yunnan province of China and provide insights for future exploration and protection, this study conducted a field survey and collection in five regions including northeastern, eastern, southeastern, southern, and northwestern. 211 collected wild germplasm resources were subjected for morphology observation and fruit quality quantification (including sugar and acid and VC contents), and genotyped using ten SSR primer pairs. Most of these genotypes were classified belonging to the A. chinensis Planch and the A. deliciosa, and the remaining genotypes were the Jingli Actinidia Lindl, the purple-fruited Actinidia Lindl., and the Gongshan Actinidia Lindl. In Zhaotong city from northeastern Yunnan the abundant and extensive distribution of wild Actinidia Lindl germplasm resources were observed. The analysis on fruit morphological traits revealed a rich phenotypic diversity. The total sugar content of 66 resources ranged from 0.08% to 8.90%, and 57.58% of genotypes showed 0.08%-5% on total sugar content. 45 resources had total acid content ranging from 0.75% to 2.90%, and 71.11% of genotypes showed 1%-2%. The VC content of 61 resources ranged from 4.74-523 mg/100 g, and 78.69% of genotypes showing VC content below 100 mg/100 g, 19.67% of genotypes (VC content between 100-200 mg/100 g), and 1.64% of genotypes showing over 200 mg/100 g were observed. The significant diversity on the total sugar, total acid and VC content were identified in the wild resource collection. Based on the phenotypic datasets, seven elite wild germplasm resources were identified. Moreover, genotyping using 10 pairs of SSR primers produced 421 bands with 100% polymorphism, with an average effective allele number of 1.0772 and the Shannon's information index of 0.1246. These markers were able to classify 211 germplasm materials, implying the rich genetic diversity of Actinidia Lindl. germplasm resources. Collectively, this study provided useful germplasm resources to accelerate the research and utilization of Actinidia Lindl. germplasm resources in Yunnan province of China.
2022, 23(6):1682-1695. DOI: 10.13430/j.cnki.jpgr.20220629002
Abstract:488 Malus germplasm resources, including cultivates, wild species, ancient cultivates and ornamental crabapple cultivar, were evaluated for fire blight resistance by in vitro inoculating young leaves and shoots. A difference on resistance revealed by two inoculation methods (leaves vs. shoots) was observed, and a higher proportion of germplasms showing resistance were detected by inoculating the young shoots. The germplasm of different species, origins and pedigrees represented significant different on disease resistance. The results of young leaves inoculation showed that the proportion of resistant resources in cultivates and wild species was higher than that in ancient cultivates. The proportion of resistant resources of McIntosh strains and Golden Delicious strains was higher than that of other strains. By analyzing the passport information of 189 Malus sieversii resources, these resources showing resistant were mainly from Uzbekistan and Xinyuan County of Xinjiang autonomous region, China. The young shoots inoculation revealed a similar pattern with young leaves inoculation except for Malus sieversii, which had higher proportion of resistant resources from Uzbekistan and Gongliu County of Xinjiang autonomous region, China. There were 187 Malus germplasm resource showing consistent results revealed by both inoculation methods, of which the McIntosh strains showed strong resistance, and majority of the Malus sieversii resources showing resistant were collected from Uzbekistan and Xinyuan County of Xinjiang autonomous region, China. The eight Malus germplasm resources were observed with high ressitance against fire blight, including six cultivates that could be used as the parents for germplasm innovation and cultivar breeding, as well s two Malus sieversii resources that could be used as basic materials for cultivar and rootstocks breeding.
2022, 23(6):1696-1708. DOI: 10.13430/j.cnki.jpgr. 20220523001
Abstract:Glufosinate is a non-selective broad-spectrum herbicide applicable in weeds control worldwide. However, in China there is no glufosinate-tolerant rapeseed variety with independent intellectual property rights to date. In this study, a glufosinate-resistant gene Syn1-RePAT was successfully transformed to the Brassica napus via Agrobacterium tumefaciens-mediated hypocotyl method, and 27 transgenic plants were obtained. The transgenic lines with a single copy of T-DNA insertion were identified by Southern blot analysis, and some of them on T-DNA copy number variation were analyzed by progeny segregation assay. The T-DNA insertion sites in the lines of OV40-7, OV40-15, OV40-16 and OV40-17 were identified by inverse PCR method. The stability of the T-DNA insertion was further confirmed by insertion-specific PCR in their T1 to T3 generations. RT-PCR and qRT-PCR expression analysis revealed that the Syn1-RePAT gene was stably overexpressed in different generations of transgenic lines. Treatments with different doses of glufosinate indicated that lines OV40-6, OV40-7 and OV40-16 were tolerant to at least six times of the recommended dose of glufosinate in production. Thus, the novel glufosinate -tolerant rapeseed lines generated in the present study will lay the foundation for the herbicide- tolerance rapeseed breeding in China.
2022, 23(6):1709-1717. DOI: 10.13430/j.cnki.jpgr.20220419006
Abstract:CRISPR/Cas9-guided gene editing technology has become a popular and precision strategy in innovation of new plant germplasms and directional improvement of agronomic traits. The GS3 and qGL3 genes are the major regulating factors contributing rice grain elongation, and loss-of-function mutants result in enlarged grain size. To obtain new inheritable large grain rice germplasms, this study deployed CRISPR/Cas9 genome editing technology to edit GS3 and qGL3 genes in the japonica rice variety ‘Nanjing 5055’ showing small grain shape. Through agrobacterium-mediated genetic transformation of pYLCRISPR/Cas9 editing vector that carries GS3-gRNA and qGL3-gRNA, we obtained the GS3- and qGL3- edited plants, with the editing efficiency over 88%. In comparison with the wild-type ‘Nanjing 5055’, the GS3-edited lines showed about 9% increase on grain length, 12.5% increase on 1000-grain weight, as well as about 9.3% decrease on grain number per panicle. Interestingly, there was no significant difference in panicle number, panicle length, seed setting rate and yield per plant. For qGL3-edited lines, ca. 21.0% and 31.7% increases on grain length and 1000-grain weight, respectively, and ca. 31.5% decrease on grain number per panicle were observed. An increase on panicle number and a decrease on seed setting rate in qGL3 edited lines were detected if compared to those of ‘Nanjing 5055’, while no differences on panicle length and yield per plant were found. The contribution of qGL3 gene to grain shape and grain weight was significantly greater than those of GS3. Collectively, this study identified a series of new rice germplasms with enlarged grain size via genome editing of the GS3 and qGL3 genes in ‘Nanjing 5055’, which might have significant implications for grain size improvement in rice.
2022, 23(6):1718-1725,1736. DOI: 10.13430/j.cnki.jpgr.20220519001
Abstract:Soybean () is one of the main sources supplying human dietary protein, and increasing its protein content is one of major targets in soybean breeding. Identification of the genes modulating the protein content is of great significance in breeding of soybean varieties with higher protein content. In this study, the F2:16 and F2:17 recombinant inbred lines (RIL) populations derived from ‘Zhonghuang 35’ and ‘Tokachi nagaha’ were applied to delimit the previously-mapped protein content locus qPRO-19-1. By sequencing the candidate genes in the interval, an InDel marker in Glyma.19g223300 between parents and five polymorphic markers from 22 SSR markers were developed. The physical interval harboring qPRO-19-1 was further delimited from 384 kb to 68.03 kb, including four annotated candidate genes, of which Glyma.19g221800 and Glyma.19g222000 showed extremely significant difference on transcript level at different stages of seed development. These results provided a basis for future map-based cloning and molecular marker-assisted breeding of this protein content-related gene in soybean.
2022, 23(6):1726-1736. DOI: 10.13430/j.cnki.jpgr.20220420002
Abstract:Cold tolerance at the bud bursting stage is an important target of rice breeding in double-cropping rice region of South China. The achievements have been made in mapping QTL, whereas these QTL have not been effectively used in rice breeding. Identification and pyramiding of QTL are of interest to achieve a breakthrough in rice breeding for cold tolerance at bud bursting stage. In this study, single segment substitution lines (SSSLs) derived from a cross between cold-tolerant japonica variety ‘IR65598-112-2’ and a popular indica variety ‘Huajingxian 74’ were used to detect and pyramid QTL for cold tolerance at the bud bursting stage. Two QTL qCTBB-3 and qCTBB-12 were identified by evaluating the difference of cold tolerance between SSSL and their recurrent parent ‘Huajingxian 74’. The SSSLs carrying qCTBB-3 or qCTBB-12 showed higher seedling survival percentage than that of their recurrent parent ‘Huajingxian 74’ after cold treatment. Through substitution mapping, two linked cold-tolerant QTL (qCTBB-3a and qCTBB-3b) were found in qCTBB-3 region. Furthermore, QTL pyramiding was performed by inter-cross of SSSLs carrying the cold-tolerant QTL (qCTBB-3a/qCTBB-3b, and qCTBB-6 identified in the previous study) and marker-assisted selection (MAS). The lines harboring three QTL showed cumulative effects on cold tolerance. Collectively, by identification of two cold-tolerant QTL and generation of the pyramiding lines with three QTL, this study provided the genes and parental lines in molecular breeding for cold tolerance at the bud bursting stage in rice.
2022, 23(6):1737-1745. DOI: 10.13430/j.cnki.jpgr.20220419001
Abstract:Stem diameter is an important trait that affects the plant architecture in maize (Zea mays L.). In order to study the genetic mechanism of stem diameter in maize, a recombinant inbred line (RIL) population (241 lines) derived from Zheng58 and D863F was used to determine the stem diameter at two environmental conditions, followed by QTL mapping using the best linear unbiased prediction values (BLUP). A total of 6 QTL for stem diameter were detected on chromosome 3, 6 and 10, each of which contributes to the phenotypic variance ranging from 4.30 to 10.73%. By transcriptome analysis, 106 (D863F/Zheng58) differentially expressed genes (DEGs) were identified in the physical intervals of the QTL. Forty-nine genes were up-regulated and 57 genes were down-regulated. GO functional enrichment analysis showed that most of the DEGs were enriched in molecular functions, including catalytic activity, transferase activity, malate dehydrogenase activity, ion binding and so on. KEGG enrichment analysis showed that the DEGs were mainly concentrated in biosynthesis of secondary metabolites, alanine, aspartate and glutamate metabolism, and phenylpropanoid biosynthesis. Twelve candidate genes were identified by integrating analysis of QTL mapping and RNA sequencing. These results enabled future fine mapping and functional analysis of these QTL and their candidate genes, which might provide a reference in marker-assisted maize breeding for ideal architecture.
2022, 23(6):1746-1755. DOI: 10.13430/j.cnki.jpgr.20220707001
Abstract:The physical properties of sorghum grains are the key factors affecting liquor-brewing process, and identification of QTL/genes for these traits is of great significance for genetic improvement in liquor sorghum. In this study, the recombinant inbred line population (RIL) consisting of 244 lines from two parental lines ‘654’ and ‘LTR108’ was genotyped using whole-genome resequencing technology, and an ultra-high-density genetic map with 3418 Bin markers was constructed. In 2021 and 2022, the thickness and color of pericarp and testa of 244 RILs were investigated at two locations (Lingshui city and Ledong city, Hainan province, China). Using complete interval mapping (ICIM), a total of 25 QTL for seven traits (exocarp thickness, mesocarp thickness, pericarp thickness, testa thickness, total thickness, exocarp color, and testa color) were identified on chromosomes 1, 2, 3, 4, 5, 8, and 10. An important QTL on chromosome 2 (57.83-57.96 Mb) was repeatedly detected across multiple traits and multiple environments, which is co-localized with the Z locus that controls the mesocarp thickness. Three candidate genes (Sobic.002G204200, Sobic.002G206700 and Sobic.002G206750) were identified and annotated by sequence homology to encode for ubiquitin family proteins and polyamine anabolism-related proteins, and they were reported involving in regulating seed size formation in other crops. This study laid the foundation for Z gene cloning and molecular marker assisted selection technique in liquor sorghum breeding.
2022, 23(6):1756-1765. DOI: 10.13430/j.cnki.jpgr.20220420001
Abstract:Starch is the main physiochemical basis for rice grain quality, and fine tuning of the starch content/composition is an important target in rice quality breeding. This study attempts to uncover specific rice germplasms that contain different starch content and determine their genotypes, in order to provide useful information for understanding the regulation network of rice starch synthesis as well as quality rice breeding. 119 rice accessions, which were collected from National Observatory of Rice Germplasm (Nanjing, Jiangsu), were examined for the amylose content using an improved method without boiling water bath. The Wx genotypes with extremely high and low amylose content were genotyped by a dCAPS marker. Out of the resistant starch content of 15 accessions with high amylose content, three were genotyped for SSIIIa and SBEIIb if compared to Nipponbare. The results showed that the updated method showed an accuracy similar to the current national standard, but became simpler and easier in the operation procedure. Most of accessions showed 9.0%-33.0% on the amylose content, and 1.0%-4.5% on resistant starch content. The genotyping using dCAPS marker showed the Wxa allele generally in the Wx genotypes of high amylose accessions. Compared with Nipponbare, three accessions (including Lixinjing, Nantehao and Chenwan3) with high resistant starch contained three common mutations in SSIIIa, among which the 2362th nucleotide in the third exon resulted in a missense mutation. Likewise, a common missense mutation in the 96th nucleotide in the fourth exon of SBEIIb gene was detected in two high resistant starch accessions (Lixinjing and Nantehao). These missense mutations might be responsible for the increase of resistant starch content in rice, providing insights for precisely editing of key genes and creating new germplasms associated with starch quality traits.
2022, 23(6):1766-1781. DOI: 10.13430/j.cnki.jpgr.20220401001
Abstract:Light harvesting chlorophyll a/b-binding protein (Lhc) directly affects the efficiency of photosynthetic system and crop yield. Wheat is one of the staple food crops in China, while the abiotic stresses seriously destabilize the yield and quality in its lifecycle. In order to systematically study the characteristics of wheat Lhc gene family members, in this study, the bioinformatics analysis and the transcriptional profile analysis of differently expressed genes or highly expressed genes were carried out. 96 Lhc genes were identified based on wheat reference genome sequence. Except that four genes (TaLhca5.1, TaLhcb1.31, TaLhcb1.39 and TaLhcb1.29) were not assigned to the chromosomes, the remaining genes were found on 19 chromosomes except 3A and 3D. The Lhc genes belong to three subfamilies in phylogeny, with each family having the similarity on gene structure and motif. In the promoter region of Lhc genes, a large number of stress response elements and growth and development related response elements were found. Expression patterns of Lhc gene in root, stem, leaf, spike and grain are different, while a higher expression was observed in leaves. Transcripts of genes TaLhca3.3, TaLhcb1.7 and TaLhcb1.20 were increased initially, followed by a decrease, whereas a decrease on gene expression of the gene TaLhcb1.46 was detected.
2022, 23(6):1782-1792. DOI: 10.13430/j.cnki.jpgr.20220415001
Abstract:The root system is a major organ for water and nutrient uptake. Exploration and utilization of the genes that regulate root development are important for enhancing wheat production. bHLH (basic Helix-Loop-Helix), a transcription factor family widely present in plants, plays an essential role in regulating the growth and development of plants. In this study, the TabHLH123-6A gene was isolated based on sequence homology, with an open reading frame of 1386 bp that encodes a protein comprises of 461 amino acids containing a conserved HLH domain. Based on the prediction of interacting proteins, TabHLH123-6A might be able to interact with HLH family members and zinc finger proteins. qRT-PCR analysis revealed the transcript of TabHLH123-6A in various tissues of wheat at different stages, with higher expression level in roots and root bases than that of other tissues. The promoter sequence analysis detected a number of cis-acting elements, including hormone response elements such as auxin, abscisic acid and methyl jasmonate. The expression of TabHLH123-6A was inducible under the treatments of auxin, abscisic acid or methyl jasmonate, but significantly repressed by PEG treatment. A nucleotide variation (C/T) at 25 bp of TabHLH123-6A gene (designated as TabHLH12325-C/T) was found using a panel of wheat accessions. A functional marker dCAPS-KpnI of TabHLH123-6A was developed to target this polymorphic site. Association analysis showed this polymorphism being significantly correlated with the ratio of deep root in wheat. The ratio of deep root with TabHLH12325-C allele is higher than that of TabHLH12325-T, and the frequency of TabHLH12325-T has been positively selected in the breeding process. Collectively, this study provided the theoretical basis and a locus for the improvement of wheat root system architecture.
2022, 23(6):1793-1806. DOI: 10.13430/j.cnki.jpgr.20220328003
Abstract:Proline is a ubiquitous osmotic regulator that plays an important role in plant growth and development as well as signaling pathways in response to drought stress. P5CS, δ-OAT, P5CR, ProDH, P5CDH and ProT are the key enzymes that affect proline accumulation in plants. However, the members of the gene families related to proline accumulation in soybean remained to be systemically investigated. In this study, seven GmP5CS, two GmOAT, two GmP5CR, five GmProDH, three GmP5CDH and six GmProT genes were identified and found to be unevenly distributed on 12 of 20 soybean chromosomes, showing 16 pairs of fragment duplication events. The phylogenetic analysis showed that the soybean proline accumulation-related gene families were classified into different evolutionary branches, while within each branch a conservation on functional structure and motifs was observed. Analysis of cis-acting elements in these gene families revealed contained cis-acting elements that were reported associating with response to stress and plant hormones. Analysis of transcriptional profiles under drought stress treatment showed that the proline anabolism-related (GmP5CS, GmOAT, GmP5CR) gene family members were significantly up-regulated 24 hours post treatment, the proline catabolism-related gene family members (GmProDH, GmP5CDH) were significantly down-regulated, and the expression levels of proline transport-related gene family members (GmProT) were significantly up-regulated. Especially, GmP5CS5, GmOAT1, GmProT subgroup II and GmProDH3-5 genes may play key roles in proline accumulation under drought stress. Moreover, the P5CS and OAT activity of soybean seedlings, which was significantly increased along with the increase of drought stress time, positively correlated with proline accumulation. The ProDH activity was significantly decreased along with the increase of drought stress time, and was negatively correlated with the accumulation of proline. Collectively, this study provided information for further analyzing the functions of soybean proline accumulation-related family genes in response to drought stress.
2022, 23(6):1807-1815. DOI: 10.13430/j.cnki.jpgr.20220517003
Abstract:Celery flowers, with the characteristics of small organ, many flowers, and in-consistent flowering time and small seeds, are considered as limits in cross breeding and seed production. The application of complete male sterile materials might bring the positive significance in celery breeding and seed production market. In this study, the genotype 'Jinnan celery' was mutagenized by radiation mutation in 2017, and a male sterile material (named: QCBU-001) was identified. By conducting the field trails over several years, this genotype showed completely male sterile without pollens, and maintained full function to pollinate with foreign pollens and produce seeds. With the preliminary results, the hybrid seeds were able to germinate and grow normally, with an obvious hybridization advantage. Sequencing of the mitochondrial genome in 'QCBU-001' enabled an assembly of 260,772 bp, containing 52 annotated mRNAs, 21 tRNAs and 7 rRNAs. The sequence analysis in released sequences of the celery sterile material 'W99A' and fertile material "W99B", as well as the mitochondrial gene cloned from 'Jinan Shiqin' revealed that 'QCBU-001' sterility was caused by Cox 1 mutation. Therefore, 'QCBU-001' is CMS male sterile material of celery, which can be used in celery cross breeding and seed production.
2022, 23(6):1816-1827. DOI: 10.13430/j.cnki.jpgr.20220330004
Abstract:Lycium is an important economic genus belonging to solanaceae. It is widely distributed in Northwest China and highly adaptable to the environment. In this study, SSR markers were developed based on the full-length transcriptome of Lycium variety ‘Ningqi 1’, followed by genotyping of 28 Lycium germplasm using a subset of polymorphic SSR markers. SSR loci were in silico identified using MISA software and subjected for primer pickup. Twenty-three SSR markers selected from 206 pairs of primers were used for genotyping and analyzing the genetic diversity of Lycium barbarum germplasm from 28 different distribution regions. Genetic coefficients were clustered by unweighted group average (UPGMA) method. A total of 240 alleles were amplified using 23 SSR markers with 4 to 17 alleles at each locus. The maximum Shannon information index was 1.177 to 2.487. The expected and observed heterozygosity ranged from 0.635 to 0.909 and 0.250 to 0.964, respectively. PIC ranged from 0.58 to 0.902. The genetic distance clustering analysis suggested four groups in 28 Lycium germplasm (similarity coefficient = 0.71). The Ningqi series germplasm belonged to group Ⅰ, the Tianjing series and Guangdong germplasm belonged to group Ⅱ, the Lycium ruthenicum germplasm belonged to group Ⅲ, and only Gouqi Island germplasm belonged to group Ⅳ. The total length transcriptomic sequence of Ningqi 1 could be used to develop SSR markers. Collectively, the full-length transcriptome sequences of Lycium are of interest to develop SSR markers, and these newly-developed SSR markers can be used for genetic diversity analysis of Lycium germplasm and molecular marker assisted breeding.
2022, 23(6):1828-1834. DOI: 10.13430/j.cnki.jpgr.20220414003
Abstract:Identification of super-male plants is the key to all-male breeding in asparagus, while traditional method based on analyzing the separation ratio of hybrid offspring remains time-consumption and cost. It is of practical value to design and develop sex-specific markers assisted for asparagus super-male plant selection. In this study, 968 selfing populations of andromonoecious plants were constructed. STS bimolecular markers YSM and XSM, which can amplify the Y chromosome specific region gene SOFF and the X chromosome specific region gene WIP2/NTT, respectively, were produced. Based on the genotyping result using STS marker, 58 super-male plants carrying a single 293 bp fragment, 550 female plants carrying a single 245 bp fragment, as well as 360 male plants with two fragments (245 bp and 293 bp) were identified. Sanger sequencing of the 293 bp and 245 bp fragments revealed a sequence identity to the reference. By making crosses using 418 male plants, 58 F1 offspring lines were all male, thus revealing a super-male status for their male parents. 360 F1 families contained male plants and female plants, proving that their male parents were male. This result is coincident with that of STS molecular marker genotyping. Collectively, the STS bimolecular functional marker can accurately classify the sex status (female, male and super-male plants) of asparagus, which has implication in the all-male molecular marker assisted breeding of asparagus.
2022, 23(6):1835-1846. DOI: 10.13430/j.cnki.jpgr.20220611001
Abstract:Pecan [Carya illinoinensis (Wangenh.) K. Koch] is an important woody oil plant and a famous nut tree species, which has been widely cultivated in China. Adequate identification of different cultivars is showing the top priority in marketing. This study aimed to develop SSR markers which would be used for analyzing the pecan genetic diversity and constructing the molecular fingerprint and IDs. A total of 80 primer pairs were used for analyzing the polymorphisms in eight cultivars. Twenty-three (28.75%) SSR primer pairs from 13 chromosomes could amplify the target fragments. These primers were further used for genotyping in 45 samples of 36 pecan cultivars, such as ‘Pawnee’, ‘Mahan’, ‘Stuart’, ‘Kanza’, and ‘Shawnee’, and produced a total of 70 alleles in all samples. Eighteen primer pairs were detected with polymorphisms in different cultivars, showing the number of alleles (NA) ranged from 2 to 8, and the polymorphism information content (PIC) values from 0.03 to 0.72. The genetic distance between different cultivars ranged from 0.026 to 0.6359, and the genetic distance between samples from different sources of the same cultivar ranged from 0 to 0.0127. A dendrogram generated by the UPGMA method suggested three groups, of which group I contained 32 cultivars and most of them have the genetic backgrounds of ‘Schley’, ‘Success’, and ‘Major. Group II and Group III contained three and one cultivars, respectively. By use of (at least) five SSR primer pairs, including Ciz91, Ciz85, Ciz81, Ciz140, and Ciz107, all the cultivars were classified. These primers were selected as core SSR markers to construct molecular fingerprints and IDs. The molecular IDs were illustrated as bar codes and QR codes. Collectively, this study provided markers applicable for the cultivar identification and traceability in pecan, which has implication in the progress of pecan cultivation and production.
2022, 23(6):1847-1855. DOI: 10.13430/j.cnki.jpgr.20220510001
Abstract:The restoring ability of restorer lines plays an important role in the fertility stability of three line F1 hybrids. In this study, two soybean cytoplasmic male sterile F1 hybrids, which were produced with the same male sterile line pollinated by restorer lines showing strong and weak different restoring ability, respectively, were used. The transcriptome sequencing of mixed flower buds of different sizes was carried out at the flowering stage. Through comparative analysis, according to "p-value < 0.05 and | log2foldchange | > 1" as the threshold in F1 hybrid (weak restorer) if compared to that in F1 hybrid (strong restorer), 2060 differentially expressed genes (DEGs) were identified including 1446 and 614 DEGs were down-regulated and up-regulated, respectively. The transcripts of several genes using quantitative real-time PCR (qRT-PCR) analysis were coincident with the results of RNA sequencing (RNA-Seq). The significance enrichment analysis of gene ontology (GO) showed that the main differential biological functions were cell periphery, pectinesterase inhibitor activity, pectinesterase activity, cell wall and external packaging structure. The enrichment analysis of kyoto encyclopedia of genes and genomes (KEGG) pathway showed that the main differential metabolic pathways were pentose and glucuronate interconversions, plant pathogen interaction and glycolysis / gluconeogenesis. According to the results of differential transcriptional genes analysis and literature reports, it is speculated that the fertility stability of soybean cytoplasmic male sterile F1 hybrid was related to the genes involved in pollen cell wall development, carbohydrate metabolism and plant pathogen interaction. When the functional balance was challenged due to the changes of environmental conditions, the sterility and fertility would be switched. Collectively, this study provided valuable information for understanding the molecular mechanism of cytoplasmic male sterility and fertility restoration in soybean from the aspect of fertility stability.
2022, 23(6):1856-1866. DOI: 10.13430/j.cnki.jpgr.20220527001
Abstract:MicroRNAs are non-coding small RNAs with regulatory functions, which modulate the growth and development, secondary metabolism and stress response in plants. To explore the miRNAs that are relevant to anthocyanin synthesis in pigmented potatoes, in this study the miRNAs and their target genes were identified using small RNA (sRNA) and degradome sequencing. The physicochemical properties, protein structure, regulatory relationship and expression of miRNAs and target genes in pigmented potato cultivars were analyzed. The results showed that, the miRNA/target gene pair stu-miR156a_R-1/StSPL9, stu-miR828/StMYB3, stu-miR858/StMYB4 and stu-miR5021/StMYB were found with significant negative correlation at different developmental stages in potato tubers. For examples, the miRNA stu-miR828 might negatively regulate the target gene StMYB3, thus inhibiting anthocyanin synthesis, while stu-miR156a_R-1 might promote anthocyanin synthesis via negatively regulating the target gene StSPL9. stu-miR858 was able to negatively regulate the target gene StMYB4, which could promote anthocyanin synthesis in purple potato cultivars and inhibit anthocyanin synthesis in red potato cultivars. stu-miR5021 was a negative regulator for the target gene stMYB, thus suppressing anthocyanin synthesis in purple potato, whereas promoting anthocyanin synthesis in red potato.