2019, 20(5):1093-1102. DOI: 10.13430/j.cnki.jpgr.20190505003
Abstract:Founder parent, which serves as type of the important germplasm resources, plays a pivotal role in update of new varieties. In the view of long-item breeding practices, the update of new varieties is tightly connected with the discovery, development and the effective utilization of founder parents in staple crops. Considering the significant contributions of founder parents in breeding, here we summarize the progress about founder parents in staple crops, which might provide insights on characterization, production contribution and genetic basis for founder parents, and which might propose the research directions and priorities in the future.
2019, 20(5):1103-1109. DOI: 10.13430/j.cnki.jpgr.20190513002
Abstract:Wild relatives are natural gene pools for crop germplasm innovation and improvement. 30% of global crop yield growth is contributed by the application of crop wild relatives. However, due to habitat destruction and pollution, overuse of resources, blinded introduction of varieties and climate change, the wild relatives of crops are under threat and a proportion of natural populations and population genetic diversity have been lost. In-situ conservation is an important strategy to protect wild relatives and their nature habitats as well as protect interaction between wild relatives and environment to maintain their evolutionary potential. Based on the summary of domestic and foreign policies and technical means of in-situ conservation, this paper summarizes the technical route of in-situ conservation, puts forward the problems and working focus of in-situ conservation of crop wild relatives in China. The large data related to genome, phenotype and environment should be closely integrated with in-situ conservation of crop wild relatives, which provide strong theoretical support for the in-situ conservation of crop wild relatives.
2019, 20(5):1110-1117. DOI: 10.13430/j.cnki.jpgr.20190322001
Abstract:China is a great country in terms of plant genetic resources, and tremendous achievements have been made in conservation and use of plant genetic resources for food and agriculture (PGRFA). However, China has not yet acceded to the International Treaty on Plant Genetic Resources for Food and Agriculture (ITPGRFA). Over the past ten years, the implementation of the ITPGRFA has been moving into more extensive level and had different impacts on China. Currently, the conservation and use of PGRFA in China is still confronting new challenges in some respects. China’s accession to the ITPGRFA could bring a lot of opportunities for China. Specifically, China would be able to have access to PGRFA in the Multilateral System conveniently and guarantee sustainable use of PGRFA at the domestic level. Moreover, accession to the ITPGRFA could enable China to be eligible to participate in the benefit-sharing activities and receive financial support under the ITPGRFA’s Funding Strategy, and in the international negotiations and norm-making in the field of PGRFA. It is recommended that national competent authority adopt relevant measures to promote China’s accession to and implement the ITPGRFA.
2019, 20(5):1118-1128. DOI: 10.13430/j.cnki.jpgr.20181223001
Abstract:Maize Stalk rot is one of the important diseases, which are occurring in corn cultivating regions of China and abroad. Due to increasing mechanical harvesting and grain direct harvest, stalk rot has become the most threatening disease in maize production. The cultivation of resistant varieties is the most economic and effective measure to control stalk rot. This paper reviews the research progress of stalk rot on aspects of the distributing regions, pathogenic species, resistant germplasm screening, resistance inheritance and disease resistance gene discovery and localization, which will lay an important theoretical foundation for IPM of this disease.
2019, 20(5):1129-1133. DOI: 10.13430/j.cnki.jpgr.20190211001
Abstract:Wheat stripe rust, caused by Puccinia striiformis f.sp tritici (Pst), is one of the most destructive disease in winter wheat. This disease seriously threats the production in areas of Gansu province, including Tianshui and Longnan. Planting varieties with genetic resistance was the most economical, environmentally friendly and effective method to control wheat stripe rust. In this article, the recent progress on monitoring virulence of Pst CYR34 and breeding for its resistance in Gansu province was summarized. Took advantage of the practice experiences over the past years, we proposed the future aspects in wheat breeding for CYR34 of Pst. We expect to provide solutions on sustainable management to wheat stripe rust, in order to ensure the security of wheat production in Gansu province of China.
2019, 20(5):1134-1140. DOI: 10.13430/j.cnki.jpgr.20190227001
Abstract:Plant Trihelix transcription factors (TFs) generally exhibit three continuous alpha-helixes within the DNA binding domain. Since these TFs were first found to specifically bind with GT elements, this family was also referred the GT factor family. Recent achievements showed that Trihelix transcription factors were involved in light response, and also various types of biotic and abiotic stresses. Here the structural characteristics and family classification of plant Trihelix transcription factors were summarized. As example of the gene expression patterns of GT-1 subfamily in sugar beet and the latest research progress, we reviewed the interactions between Trihelix transcription factor and environmental factors. This will lay a foundation for further exploring the molecular mechanism of Trihelix transcription factors being involved in plant light response as well as biotic and abiotic stresses.
2019, 20(5):1141-1150. DOI: 10.13430/j.cnki.jpgr.20190129001
Abstract:Breeding for drought-tolerance varieties is one of the most cost-effective ways to meet global climate drought, and identification of the drought-tolerance germplasms is of importance in breeding. In this study, 303 mungbean accessions were tested for drought tolerance under the different irrigation conditions in Qitai Xinjiang in 2017 and 2018. Nine parameters were investigated, for instance yield per plant, pod number per plant, seed number per plant and biomass per plant. The ratios of all parameters between drought and irrigation condition were calculated. The drought tolerance indicators were determined by correlation analysis, and mungbean germplasm for drought-tolerance were evaluated by drought tolerance coefficient, subordinative function analysis and drought tolerance index. Based on the identified suitable evaluation method, we conducted the screening for drought-tolerance germplasm. The significant positive correlations on drought tolerant coefficient were observed between drought and irrigation conditions for pod number per plant, seed number per plant, biomass per plant and yield plot. The four indices were recommended for drought tolerance identification in mungbean. The correlations were significant among parameter values of three evaluation methods with a very high consistency. The drought tolerance germplasm resources, which were identified by the drought tolerance index, exhibited higher average yield per plant than by the two other methods under different water regimes. This results implied that the drought tolerance index was optimal to screen a large number of germplasm resources of mungbean at natural condition. 103 accessions, which showed identical results in 2017 and 2018, were finally identified. That included 9 varieties with high tolerance, 11 with tolerance, 61 with moderate tolerance, 8 with susceptibility, and 14 with high susceptibility. This results will provide theoretical guidance and basic information for future study on drought tolerance of mungbean.
2019, 20(5):1151-1159. DOI: 10.13430/j.cnki.jpgr.20190213001
Abstract:To explore drought resistance characteristics of adzuki bean at the seedling stage, 235 adzuki bean accessions from different regions were subjected for drought resistance tests upon drought stress treatment by pot cultivation assay. The root morphology, plant height, biomass and canopy wilting were measured, and the statistical analysis was conducted using the subordination function method, principal component analysis (PCA) and cluster analysis. Under drought treatment, the taproot length, lateral root length, total root length, and ratio of shoot dry mass to root dry mass were higher than those of the control groups, but taproot surface area, lateral root surface area, total root surface area, taproot volume, lateral root volume, total root volume, shoot dry mass, root dry mass, plant dry mass and plant height were lower than those of the controls. The correlation analysis on the subordination function values of each trait showed the correlation with the total root surface area. The first three principal components explained 82.8% of the phenotypic variations at 15 traits. The first, second and third principal components were mainly contributed by root surface area, dry mass, and taproot length, respectively. These accessions were classified into three types, composing of drought-resistant, intermediate and drought-sensitive, which accounted for 8%, 63% and 29% of total accessions, respectively. According to the subordination function value, principal component analysis and root morphology of different types, the total root surface area served as a major index for the evaluation of drought resistance at the seedling stage. Moreover, 15 drought-tolerant accessions were identified being valuable for further drought-resistant breeding and gene mining in adzuki bean.
2019, 20(5):1160-1169. DOI: 10.13430/j.cnki.jpgr.20181031001
Abstract:Rice is often exposed to cloudy and rainy weather during grain filling, resulting in decrease in rice yield and quality. By analyzing the meteorological data of rice grain filling during the last 6 years (2012-2017) in rice-growing region alongside the Yellow River (RAYR), it was found that the decrease of sunshine duration during grain filling period was the main climatic factor affecting rice production. 80 varieties of japonica rice from Japan and China were used for shading experiment, which created 65% reduction of full natural light making use of one layer of black netting and last 30 days during grain filling period. Light intensity, red light and far red light intensity, temperature and humidity in 3 weather conditions (sunny, cloudy and rainy) on the top of canopy were measured. And the 1000-grain weight, milling quality and chalkiness under shading were analyzed to screen shade tolerant japonica rice varieties. The results showed that in our study the temperature and humidity were no difference between shading and natural condition. The sunlight at the top of canopy was changed at two aspects, energy and signal, which indicated that radiation and R/FR ratio were both decreased under shading. 1000-grain weight, brown, milled and head rice rates were decreased, and chalky rice rate and chalkiness degree increased under shading. Among these characteres 1000-grain weight and chalkness were mostly affected by shading. Based on 1000-grain weight decrease, chalky grain and chalkness degree increase under shading, 4 high quality and shade tolerant japonica rice varieties were screened, which including Fangsiluo, Xinfeng5, Zhaoxiang3 and Xiaoxiang. Thus, these shade tolerant varieties with excellent grain quality served as valuable resource in future breeding for new resistant low-light varieties.
2019, 20(5):1170-1177. DOI: 10.13430/j.cnki.jpgr.20190327003
Abstract:The genetic diversity analysis of 43 agronomic traits was carried out in 45 Zhangpu wild rice germplasms in Fujian Province. The results showed that Zhangpu wild rice represented abundant genetic diversity. 22 of 31 qualitative agronomic traits were found with the variability of genetic differentiation. The genetic diversity indices ranged from 0.245 to 1.43, and the index of leaf color was the highest. The genetic diversity indices of 12 quantitative agronomic traits ranged from 1.86 to 2.06, of which the index of stem length was the highest, indicating that stem length possesses the most abundant genetic diversity. By correlation analysis among 12 quantitative traits, the panicle length represented closely significant positive correlation with the ligule length of flag leaf and the second top leaf, the length and width of flag leaf. 100-grain weight was found to be significant positive correlation with the flowering time and awn length. These materials were clustered into five groups: I, II, III, IV and V, of which the group V was M2042 alone.
2019, 20(5):1178-1185. DOI: 10.13430/j.cnki.jpgr.20190122003
Abstract:In order to make use of the heterosis in hybridization breeding, it is of great significance to explore excellent germplasm resources and analyze the combining ability. By deployment of 8 restorer lines and 21 sterile lines, which served as male and female parent, respectively, this study generated 168 hybrids following the incomplete diallel hybridization 8×21 (NCII). These materials were analyzed for the combining ability and the genetic parameters of 8 agronomic traits. The results showed that the effective panicle number, panicle length and 1000-grain weight were mainly affected by the additive effect, and the plant height, filled grain number and the seed setting rate were mainly affected by the interaction of non-additive effect. The plant height, effective panicle number, spike length, 1000-grain weight and yield per plant of hybrid combination were largely female-dependent, while the total grain number was largely male-dependent. The grain number and seed setting rate were genetically contributed by both parents. The effective panicle number and yield per plant were depending on the interaction between genetic components and environment conditions. The parents with combining ability were 843A, Yixiang 1A, Huhan7A, Changhui 871, Changhui T025 and Yazhan. Out of these genotypes, Yixiang 1A and Changhui T025 exhibited the best General Combining Ability (GCA) effect value. The hybrid combination Yixiang 1A/ Changxianghui 1 exhibited the excellence on Special Combining Ability (SCA), and the hybrids including Yixiang 1A/ Changxianghui 1, Qianxiang 059A/ Changhui 121, Guang8A/Changhui 881 were qualified. Thus, by investigating the combining ability of main agronomic characters in restorer lines, this study provided some scientific basis for the breeding of hybrid rice restorer lines.
2019, 20(5):1186-1196. DOI: 10.13430/j.cnki.jpgr.20190119001
Abstract:The phenotypic diversity and adaptability of 228 introduced garlic (Allium sativnm L.) germplasm accessions originated from 34 countries were evaluated in the present study. The field trial was performed at the national germplasm repository for vegetables. The coefficient of variation of 13 quantitative traits ranged from 18.94% to 56.36%. These genotypes represented visible variations on all qualitative traits except leaf shape. The diversity index of 25 traits varied from 0 to 2.03, indicating that the introduced garlic germplasm maintained high levels of genetic diversity. The clustering analysis of 228 accessions revealed three groups. The accessions within group I showed small and slender plants, short and thin leaves, and low quality bulbs. The group II was comprised of those accessions that transverse diameter of bulbs were small, and bulbs were less and the bulbs shape were high spherical. The accessions in group III mostly exhibited tall and big plants, long and wide leaves, and heavy and large bulbs. The first three principal components explained 69.94% of phenotypic variation. The bulb weight was found to be significantly and positively correlated with bulb diameter, bulb height, height of scale buds and width of scale buds. Furthermore, these accessions were variable on adaptability by comparing the measurements of bulb-related traits before planting with that of after harvest. Thus, these results will provide benefits for breeders and researchers in order to take use of the germplasm accessions in breeding programs.
2019, 20(5):1197-1212. DOI: 10.13430/j.cnki.jpgr.20181213002
Abstract:Grape (Vitis L.) is one of the most important economical fruit trees in China. However, a shattering rachis-like phenotype in some varieties is un-desirable, particularly during long-distance transport and storage. Breeding for storage-resistant varieties is one of the most effective measures to prevent this problem. In this study, six hundreds of accessions from Zhengzhou National Grape Germplasm Repository were evaluated for the pulling force of fruit stalk with a digital tension machine. Whether pulling force of fruit stalk correlated to fruit handle, fruit pedicle and fruit brush lengths were analyzed as well. The results showed that the pulling force of six grape varieties showed a decreasing trend during fruit ripening. The pulling force of fruit stalk of hard flesh is stronger than that of soft flesh varieties. The pulling force of 600 grape accessions ranged from 0.72 to 9.16N, showing a continuous distribution consistent with positive skewness distribution. The pulling force was distributed into weak (P≤3N), medium (3N＜P≤6N) and strong (P＞6N) 3 classes, with respective proportion of 73.7%, 23.8% and 2.5%. It showed that most grape accessions tested in the germplasm resources have weak pulling forces. Several grape varieties showed strong pulling force of fruit stalk, including Red Globe, MuDanhong, Mathias Aromatic and so on. The pulling force of fruit stalk in different varieties was positively correlated with the single grain weight, fruit stalk and fruit brush lengths, unit cross-section area of fruit stalk, fruit pedicle and fruit brush lengthes. Moreover, the pulling force negatively correlated with the ratio of unit cross-section area of fruit brush versus berry weight. Taken together, this research provided valuable information on characterizing the pulling force of grape germplasm resources in future breeding for new grape varieties.
2019, 20(5):1213-1222. DOI: 10.13430/j.cnki.jpgr.20190110001
Abstract:In this study, 182 wheat cultivars (lines) were tested for leaf rust resistance with mixed races of KHST, FHKT and FHJT of Puccinia triticina at seedling stage. Out of that, 14 cultivars (Taikemai5303, Zhumai305, Yushengmai118, Cunmai18, Xuanmai6, Nongfengchuan, Danmai118, Zhengmai103, Zhengmai119, Saidemai5, Zhengmai369, Xuke918, Yumai668 and AF116-120) were resistant, and the remaining cultivars (lines) were highly infected. By inoculation with 15 Pt pathotypes, which were used for clarifying Lr resistance genes, six cultivars including Zhumai 305, Cunmai 18, Nongfengchuan, Zhengmai 119, Saidemai 5, Zhengmai 369 and Xuke 918 were predicted to the carriers of leaf rust resistance genes Lr33+34. The leaf rust resistance in Zhengmai 103 was possibly caused by leaf rust resistance genes Lr10 and Lr33+34, while that of AF116-120 was possibly derived from leaf rust resistance genes Lr10, Lr16, Lr20 and Lr33+34. These cultivars including Taikemai 5303, Yushengmai118, Danmai 118 and Yumai 668 might contain other Lr genes. In addition, 25 molecular markers for 20 known Lr genes were further deployed for molecular-assisted identification. Lr1 and Lr26 were found to be present in cultivars Nongfengchuan, Xuanmai 6, Zhengmai 103 and Xuke 918, and Lr1 was detected in Taikemai 5303, Shengyumai 118, Zhengmai 119 and Zhengmai 369. Zhumai 305, Cunmai 18 and Yumai 668 carried Lr26; AF116-120 carried Lr1 and Lr2c; Danmai 118 carried Lr26 and Lr37. The results suggested that only few of wheat cultivars were found with Lr genes. Taken together, the results may lay scientistfic basis for the extension and rational distribution of cultivars, leaf rust control and wheat breeding of disease resistance in Huang-Huai-Hai wheat cultivating areas.
2019, 20(5):1223-1231. DOI: 10.13430/j.cnki.jpgr.20181226001
Abstract:To investigate the cucumber thermotolerance at seedling stage and identify heat-tolerant accessions, this study analyzed 86 cucumber core germplasm at three-mature-leaves seedlings stage under greenhouse conditions (temperature: 50±4℃). Scoring for heat damage was conducted based on heat injury symptoms, and the heat injury index (HII) was deployed to evaluate the thermotolerance of cucumber at seedling stage. Taking advantage of the whole genome re-sequencing datasets, the genome-wide association study (GWAS) was employed to identify the genetic loci that associated to the thermotolerance. The significant differences in HII were detected among tested materials, while the coefficient of variation under two environmental conditions were 21.9% and 22.5% respectively. By deploying HII, 86 cucumber germplasms were clustered into four groups: heat-resistant, medium heat-resistant, medium heat-sensitive and heat-sensitive group. The preliminary GWAS analysis suggested seven loci, including gHII4.1、gHII5.1、gHII5.2、gHII6.1、gHII7.1、gHII4.2 and gHII6.2, which were associated to the heat resistance. Among them, two loci gHII4.1 and gHII4.2 on chromosome 4, were found to be mostly relevant, and 67 candidate genes within this region were found.
2019, 20(5):1232-1239. DOI: 10.13430/j.cnki.jpgr.20181223002
Abstract:Leaf early senescence can directly reduce photosynthesis and crop yield. Unlocking the mechanism of leaf early senescence becomes important via building up the strategy to achieve high and stable rice yield. A water-soaked spot mutant (termed wss1) was identified in the population derived from EMS-treated seeds of the indica rice variety JG30. At the tillering stage, the leaves of wss1 showed premature senescence, including the appearance of water-soaked spots, which further developed to the leaf necrosis. In relative to the parental line JG30, wss1 mutant showed 30%, 22% and 50% reduction on the plant height, seed setting rate and number of grains per panicle, respectively. The chlorophyll content in the water-soaked spot leaves of wss1 was significantly lower than that of the wild-type plants. By trypan blue cell histochemical staining, the cell membrane of wss1 on leaves was destroyed. Genetic analysis showed that wss1 was controlled by a recessive gene (wss1), which was mapped in a 1200 kb region between markers Ch11-33 and Ch11-123. Thus, these results will benefit future molecular cloning and functional characterization of the underlying gene of Oswss1.
2019, 20(5):1240-1246. DOI: 10.13430/j.cnki.jpgr.20190116002
Abstract:Five blast resistance (R) genes, Pib, Pita, Pi5, Pi25 and Pi54, which showed relative broad-spectrum resistance to Chinese Magnaporthe oryzae isolates, were surveyed in the mini-core collection of Chinese rice germplasm by using their functional markers. As a result, 124 accessions of germplasm were found to harbor 1-4 target genes, respectively. Among them, Huangsiguizhan contained four R genes including Pib, Pita, Pi5 and Pi54;Nanxiongzaoyouzhan and Wuzuihonggu each harbored three R genes Pita/Pi25/Pi54 and Pita/Pi5/Pi54, respectively；35 accessions including Yelicanghua and Liaojing 287, etc. each harbored two R genes with genotypic constitutions of Pi5 and Pi54, Pita and Pi54, Pib and Pi54, Pib and Pita, Pi25 and Pi54, Pib and Pi5, Pita and Pi5, Pita and Pi25, Pi5 and Pi25, respectively. 86 accessions including Funingzipijingzi and Longhuamaohulou, etc. each harbored a single target gene. These results will provide references for grasping blast R genotypes of themini-core collection of rice germplasm and improving cultivar resistance using the elite accessions of germplasm.
2019, 20(5):1247-1254. DOI: 10.13430/j.cnki.jpgr.20181219003
Abstract:Plant height is an important agronomic trait that determines the grain yield of rice, which is one of the most important food crops worldwide. However, the molecular mechanism underlying rice height remained further investigated. In this study, we characterized a rice dwarf and small grain mutant designated dsg7 (dwarf and small grain 7) from Kitaake with seed treated by ethyl methane sulfonate (EMS). Compared with Kitaake, dsg7 showed 22% and 21% reduction on the plant height and 1000-grain weight. Histological observations showed that the dwarf phenotype was mainly due to a defect in cell proliferation. By deploying the map-based cloning strategy, the gene was finally mapped between markers DM6 and DM8 on chromosome 7, with a physical distance of 237 kb. One base pair deletion of Os07g0616000 was found, and this gene served as the best candidate. Thus, this result suggested that DSG7 might be essential for plant height development in rice and its biological function remained to be investigated in the future.
2019, 20(5):1255-1261. DOI: 10.13430/j.cnki.jpgr.20181222001
Abstract:Plant height and tillering, which served as two of important agronomic characters of rice, can determine the final yield. In this study, one genetically stable and high-tillering dwarf mutant t489 was identified from the tissue culture seedlings of ‘Nipponbare’, a japonica rice variety. Compared to the wild type, the mutant t489 showed semi-dwarf and high-tillering. The genetic analysis indicated that this phenotype was controlled by one single recessive gene. Sequence analysis of D17/HTD1 allele in the t489 mutant showed G-to-T substitution at the 916’ of the coding sequence, which caused premature termination of the D17/HTD1 encoded protein. D17/HTD1 encodes the carotenoid cleavage dioxygenase 7 (CCD7), which is one of the key enzymes in the biosynthesis pathway of plant hormone strigolactones (SLs). d17 allele encodes for a truncated protein containing 305 amino acids, while no difference on the expression level was detected in the t489 mutant. Furthermore, a molecular marker dCAPS-D17 based on the G916T mutation site was developed. By tests in BC1F2 population derived from the t489 mutant and ‘Nipponbare’, this marker was co-separated with the dwarf and high-tillering plant. Taken together, these results suggested a new d17/htd1-allelic mutant in mutant t489.
2019, 20(5):1262-1270. DOI: 10.13430/j.cnki.jpgr.20190121002
Abstract:159 genetically-variable rice varieties were tested for low potassium tolerance according to the synthetic appraisal index. The results indicated that there were 18 and 10 rice varieties that were tolerant and sensitive to potassium deficiency, respectively. By deployment of the recombinant inbred lines (RILs) that were derived from the crossing between the varieties of Tainong67 (potassium tolerant) and Zhixi (potassium sensitive), 27 QTLs for potassium deficiency resistance were detected. The LOD values arranged from 2.52 to 9.23, which explained the phenotypic variance of 2.22% to 7.25%. A major QTL qKC-2 was mapped on chromosome 2 of rice. This locus was yet reported, and might encode for an unknown gene that is valuable for future fine mapping and gene isolation. The newly-developed indel markers could be used to rapidly screen the genotypes with potassium deficiency resistance, thus shortening the breeding period. The lines with good agronomic traits and potassium deficiency resistance could be chosen from RILs and applied to rice breeding directly.
2019, 20(5):1271-1277. DOI: 10.13430/j.cnki.jpgr.20181228001
Abstract:Flower color is an important trait in Brassica oleracea which can attract and guide the insect pollinators, protect flower organs, maintain the energy homeostasis in flower, reveal the rate and purity of out-crossing and indicate the introgressions of traits. In order to identify the genetic loci and candidate genes controlling flower color in B. oleracea, we constructed an F2 population from the cross between a B. alboglabra line (white flower) and a wild B. oleracea accession (yellow flower), and conducted QTL analysis using a previous molecular-marker-based genetic linkage map and a SNP microarray. By using a previously developed genetic linkage map, four QTL for flower color were detected from chromosome C02 and C03, respectively. The QTL on C03 was identified as a major QTL (explaining 78% of the phenotypic variation) with a partial dominant effect, and the QTL on C02 was a minor QTL (explaining 8% of the phenotypic variation) with an additive effect. To confirm and delimit the QTL, a QTL-seq analysis was conducted by using the B. napus 60K SNP microarray among 63 white and 31 yellow F2 genotypes. A significant peak was detected from 48.08 to 48.92Mb (0.84 Mb interval) on chromosome C03, within the confidence interval of the C03-QTL. One candidate gene BoCCD4 which is homologous to a known gene controlling flower color in B. napus was found from this QTL region. Nearly no expression of BoCCD4 was found by QT-PCR in yellow-flower B. oleracea genotypes, while high expression was detected in white-flower genotypes. A 3-bp insertion was detected at 778-780 bp of the coding region of BoCCD4 between two parental lines, and an indel marker LJ04 was developed accordingly, exhibiting co-segregation with flower color in 133 F2 genotypes of B. oleracea and 101 DH lines of B. napus (derived from B. alboglabra with white-flower). Our results suggest that the white flower in B. oleracea is controlled by a partial dominant locus on chromosome C03 and possibly regulated by a minor additive QTL on C02. Furthermore, the 3-bp insertion in the candidate gene BoCCD4 was assumed to result in the loss of function of BoCCD4, leading to a yellow flower. Thus, this study identified a novel allele of the candidate gene controlling the flower color in B. oleracea, and this result might contribute to understand the variation and evolution of flower color in Brassica species.
2019, 20(5):1278-1288. DOI: 10.13430/j.cnki.jpgr.20190130001
Abstract:In this study, 151327 of InDels were in silico identified by taking advantage of whole genome re-sequencing of two eggplant (Solanum melongena) lines. The primers targeting 180 InDel loci were developed, which were subjected in tests of two re-sequencing eggplant lines and derived hybrid line. Out of that, sixty-two (34.7%) of total primers were polymorphic between both varieties. In addition, the genetic diversity and specificity of 24 eggplant lines and 143 varieties were investigated by use of these markers. The results from purity test of variety from two InDel markers matched well with those from field experiments.
2019, 20(5):1289-1300. DOI: 10.13430/j.cnki.jpgr.20181210004
Abstract:WRKY proteins, as one of the most important transcription factor families in plant, play important roles involved in many biological processes. However, studies of WRKY proteins in Gossypium barbadense remain scare. By deploying bioinformatic methods to perform a genome-wide characterization in G. barbadense genome, 180 WRKY transcription factors were identified. According to their structural features and topology of the phylogenetic tree, the GbWRKY genes were classified into three major groups (I-III). In addition, group II is further classified into five subgroups (IIa-IIe). The GbWRKY genes distributed unevenly on the 26 chromosomes. Analysis of gene duplication events demonstrated that the expansion of GbWRKY genes is mainly due to whole genome duplication and segmental duplication events. 61 GbWRKY genes showed significantly differential expression under Verticillium dahliae infection, implying that they might play important roles in interaction to V. dahlia infection. Therefore, this study provided the structure, evolution and expression pattern of GbWRKY genes, which will help further characterizing the functions of GbWRKY genes in Gossypium barbadense.
2019, 20(5):1301-1308. DOI: 10.13430/j.cnki.jpgr.20181210003
Abstract:SQUAMOSA PROMOTER BINDING PROTEIN-box (SBP-box) genes, that belong to plant-specific transcription factors, are involved in many important aspects including leaf?development, embryogenesis, vegetative and?reproductive?phase transitions. This family has important practical application in crop genetic improvement. In this study, we isolated a sorghum SBP-box gene named SbSBP5, and conducted the sequence analysis and the transcriptional pattern under different biotic stresses. SbSBP5 coded for a polypeptide of amino acids that contained a typical SBP domain. By analyzing the promoter sequence, several stress-related cis-elements including MBRE, ARE and MBS were detected. Twelve and 11-fold up-regulation of SbSBP5 was detected by PEG-directed drought treatment or applying exogenous abscisic acid. In transgenic Arabidopsis that expressed SbSBP5 promoter plus a GUS reporter, three and four fold of GUS activity were detected under drought or exogenous abscisic acid treatments, respectively. Thus, these results provided preliminary outcome of SbSBP5 responding to drought and exogenous abscisic acid, which might provide a basis for further unlocking its molecular function.
2019, 20(5):1309-1316. DOI: 10.13430/j.cnki.jpgr.20181218002
Abstract:Apocynum cannabinum is an important economic and ecological crop. Genetic studies on this crop remains largely behind due to the un-availability of genome reference and limited amount of molecular markers. In this study, we performed a whole genome sequencing of?A. cannabinum?by sequencing technology (Illumina), and analyzed the ratios of heterogeneity and repetitive elements, followed by exploration of SSR markers. A total of 31.94 Gb high-quality sequences (Q20 ≥ 90% and Q30 ≥ 85%) have been generated. By searches with NCBI nucleotide database (NT), no exogenous contamination in the sample was detected. De novo assembly and K-mer analysis revealed a genome size of 239.02 Mbp, with 0.56% heterozygosity and 36.72% of repetitive sequences. 273,336 contigs with a N50 of 3,838 bp in length have been detected, and the total length was 222,723,253 bp. 224,587 scaffolds were further assembled, with a N50 of 6,421 bp in length, and the total length was 226,378,236 bp. By predicting for the simple sequence repeats (SSR), 117,511 have been detected potentially for exploring SSR markers. Of all SSR categories, the mononucleotide and hexanucleotide repeat units formed the largest and the least categories, respectively. Thus, this work generated a sequence dataset that might be useful source for future?de novo assembling of?A. cannabinum genome.
2019, 20(5):1317-1324. DOI: 10.13430/j.cnki.jpgr.20190129002
Abstract:Dehydrin is the most distinctive group of proteins in the late embryogenesis protein (LEA) family, which plays an important role in plant resistance to abiotic stress. In this paper, we isolated the complete coding sequences of four dehydrin genes, designated AmDHN3.2F, AmDHN5.1F, AmDHN6.2F and AmDHN7.2, in stress-resistant evergreen broad-leaved shrub Ammopiptanthus mongolicus. The bioinformatics analysis using DNAMAN software suggested that all four genes carried one K and one S domain. The analysis of physicochemical properties showed that all four proteins belonged to hydrophilic proteins. AmDHN3.2F was alkaline protein, while AmDHN5.1F, AmDHN6.2F and AmDHN7.2 were acidic proteins. AmDHN7.2 exhibited the largest theoretical relative molecular weight (21.42 KD), and AmDHN3.2F showed the smallest weight (10.69KD). AmDHN3.2F exhibited the highest theoretical isoelectric point (PI = 9.01), and AmDHN6.2F showed the smallest isoelectric point (6.21). By in silico prediction of secondary and tertiary structure, the four dehydrin proteins composed of three types of motifs: alpha helix (7.50%-32.63%), irregular curl (55.79%-73.00%) and elongation chain (11.58%-19.50%). The phylogenetic tree constructed by Neighbor-joining method suggested that the putative proteins of four dehydrin genes were related to MtDHN3 and AtDHN10. By XSTREAM software, it was found that the protein sequences of AmDHN5.1F, AmDHN6.2F and AmDHN7.2 contained tandem repeat units, which were enriched in the middle part of dehydrin. According to the dot maps generated by DOTTER software, a large number of short repeats were found in the middle part, implying the location where the shrinkage or expansion of dehydration sequence mainly occurred. This findings lay a foundation for further functional analysis of DHN gene family in Ammopiptanthus mongolicus.
2019, 20(5):1325-1333. DOI: 10.13430/j.cnki.jpgr.20190121001
Abstract:The microsatellite markers in Firminana danxiaensis were developed by taking use of from the transcriptome dataset. These markers were subjected for analyzing the genetic diversity of extant populations to provide basis for rational utilization and the protection of Firminana danxiaensis. Primer 3.0, GenAlEx6.3, FSTAT and MS-tools were deployed to explore primers and analyze the genetic parameters. As a result, 17,858 SSRs were identified from 79,920 unigenes with a frequency of 1/4.78kb. Trinucleotide, tetranucleotide and dinucleotide accounted for 43.64%, 23.52% and 15.54%, respectively. AAG/CTT and AG/CT were the most abundant repeat motif for trinucleotide and dinucleotide, respectively. Out of seventy-three primers that were tested in 16 genotypes, 16 primers were polymorphic with an average value of polymorphic information content (PIC) 0.546. The principal component analysis (PCA) showed that these loci are efficient to identify individuals from different regions and each individuals. A moderate genetic diversity among three Firminana danxiaensis populations and the expected heterozygosity (He) varied from 0.550 to 0.605 were observed. The geology, historical climate change and human disturbance may be the main reasons for Firminana danxiaensis deviated from Hardy-Weinberg equilibrium. Taken together, these newly developed EST-SSR markers will lay foundation for unlocking the genetic structure and the marker-assisted breeding of Firminana danxiaensis.
2019, 20(5):1334-1339. DOI: 10.13430/j.cnki.jpgr.20181212001
Abstract:Broad bean (Vicia faba L.) often exhibits an average outcrossing rate of about 30%. This phenomenon greatly led to the decline of uniformity and stability of broad bean cultivars. Due to the consequences caused by the climate and pollination factors, breeding for lower outcrossing rate using normal germplasm was un-able to be well maintained. However, identification of cultivars with special flower structures, which could reduce honey forage behaviour of insect medium, is considered to be a better strategy. In this study, a natural mutation of broad bean showing short wing petal was obtained from Yunnan province and named 81-37. This character exhibited potential to impede the insects on gathering nectar, thus resulting in reduction on insect-induced outcrossing. The outcrossing rate of short wing petal type decreased from 30 % to 5% compared to the common types of broad bean. By using this mutant for crossing and back-crossing with common types of broad bean, the offsprings with the characters of short wing petal were selected for further cultivar breeding and production. This helped to keep the stability of stress resistance, adaption, growing period, flower color, seed coat and hilum color, cotyledon color, plant height, pod shape, seed nutrition, and maintained the high yield and better quality of broad bean cultivars, which prolonged the durable years of cultivars, benefited the industrial development of broad bean. Thus, this work provided a special germplasm being valuable in breeding for broad bean varieties.
2019, 20(5):1340-1348. DOI: 10.13430/j.cnki.jpgr.20181213001
Abstract:In order to decipher the genetic diversiy of persimmon germplasms, a total of 112 persimmon cultivars (Diospyros kaki) collected from Shaanxi province, 16 date plums (D. lotus) from Shaanxi and 11 persimmon cultivars from Henan province were investigated by using ten SCoT markers with high polymorphism and qualified reproducibility. The statistical assessments including polymorphisms, cluster analysis, principal coordinate analysis, population structure analysis and genetic diversity analysis was analyzed according to the geographic regions of genotypes. A total of 99 polymorphic marker loci were obtained from 10 pair SCoT primers. By cluster analysis, 16 date plums were assigned to an independent cluster, differing with the persimmon cultivars. Persimmon cultivars from Henan province and Shaanxi province are clustered together and have a close genetic distance. Although the genetic structure analysis implied an exchange on genetic components among 112 persimmon cultivars in various regions of Shaanxi Province, the genetic diversity remained limited. The cultivars from both Baoji and Xi'an cities represented the highest genetic diversity, while the lowest diversity was observed in these of Southern Shaanxi. Thus, the results could facilitate better understanding of genetic contributions in varieties, and provide a scientific theoretical basis for further investigating the persimmon resources in Shaanxi Province.
2019, 20(5):1349-1354. DOI: 10.13430/j.cnki.jpgr.20190128004
Abstract:In this study the modified wall degradation hypotonic method was used for unlocking the chromosome number and the karyotype of Urophysa rockii Ulbr., a plant species of which is distributed in an extremely restricted area. The 5S rDNA sites on chromosomes were also analyzed of Urophysa rockii Ulbr. via fluorescence in situ hybridization (FISH). The results indicated that Urophysa rockii Ulbr. is a diploid species with 14 chromosomes (n = 7). The relative length of chromosomes was 2n=14=2L+2M2+10M1, and no satellite chromosome was detected with the karyotype formula. The average centromere index and karyotype asymmetry coefficient were 44.09 and 55.91, respectively. The karyotype belonged to 1A type, suggesting that phylogenetic evolution is relatively primitive. Furthermore, two 5S rDNA sites were detected close to the centromere of the long arm of chromosome 1. Taken together, these results may provide shed-light on systematology and cytology of Urophysa rockii Ulbr.