2020, 21(2):275-286. DOI: 10.13430/j.cnki.jpgr.20190430002
Abstract:Wild grape resources play an important role in understanding the systematic evolution of Vitis L. The broad geographic distribution, natural crosses and complicated morphological variation result in the difficulty on classifying different species. The classification of some wild species were controversial. Based on the classification history of the genus Vitis, this article reviews the research progress of the wild species classification, and further outlines the shortages and our corresponding suggestions, which hopefully provide reference for the protection, utilization, classification, origin and evolution of wild grape resources.
2020, 21(2):287-295. DOI: 10.13430/j.cnki.jpgr.20190530001
Abstract:Saccharum spontaneum L. is the closest relative wild species to the modern sugarcane cultivar. Considering the capacity on resistance to a variety of adverse environments, it was popularly used as donors in sugarcane breeding for resistant cultivars. To date, only a few of S. spontaneum clones and their resistance genes have been incorporated effectively into sugarcane commercial varieties, and the most of present cultivars have a single or weak resistance capacity and a narrow resource of resistance genes. It is of great significance to enhance the researches on screening of superior breeding parents with high stress resistance and mining of stress resistance genes from the wild germplasm such as S. spontaneum. This review summarized the past and current research progresses on stress tolerance identification, cloning of resistant genes as well as functional validation from different S. spontaneum genotypes, for instance in fields of drought/chill tolerance and insects/pathogen diseases infections. The current problems and future prospects of the highly resistant genotypes screening and gene mining are also discussed. We expect to provide better understanding on the resistant variance from genotypes, and insights in efficient use of the rich resistant gene pool for future sugarcane breeding of multiple resistance polymerization.
2020, 21(2):296-307. DOI: 10.13430/j.cnki.jpgr.20190422001
Abstract:In order to protect and utilize ancient tea plant resources, general survey of ancient tea plant resources were conducted in 58 counties of 12 prefectures from Yunnan province from 2010 to 2017. Following the instruction of the Flora of China, a database including these resources and the geographical distribution database were established. On this basis, the ancient tea plant resources in Yunnan were studied about their species composition, geographical distribution characteristics, habitat types and morphological diversity, with the help of geographic information system and statistical analysis. As a result, 474 spots of ancient tea plant resources and 2570 ancient tea plants, which are clarified in 7 species and 6 variants, were identified, implying an abundance of ancient tea plants distributed in this area. These resources were often distributed in Western Yunnan, Southern Yunnan, Southeastern Yunnan and Ailao Mountain Chain. Out of that, Southeastern Yunnan was recognized as a center of the species diversity, and Western Yunnan was a center of endemic species. Three geographic distribution centers containing Camellia taliensis, C. sinensis var. assamica and C. crassocolumna were proposed, consisting of Western Yunnan, Southern Yunnan, and Southeastern Yunnan. Ancient tea plant resources were found with diversifying habitats, and they distributed in primary forest, secondary forest and alpine cultivated land areas. The genetic diversity index of the descriptive characteristics were ranged from 0.58 to 2.05. The abundant morphological diversity was observed with the variation coefficient of 4.37% to 51.03%. A higher variability of vegetative vs. reproductive organs were visualized. Taken together, this study provided important information for the evolution, diversity conservation and rational utilization of ancient tea plant resources in Yunnan, which allowed raising some suggestions on the future protection and exploitation.
2020, 21(2):308-313. DOI: 10.13430/j.cnki.jpgr.20190703001
Abstract:Crown Rot caused by Fusarium species is a worldwide soil-borne disease in several crop species. In recent years, crown rot became a common threat in many wheat-growing regions in China. However, the reports on large-scale screening of crown rot resistant resources remain rare. In this study, 670 Chinese wheat germplasms plus two genotypes Sunco and Shan253, which served as resistant and susceptible control, respectively, were evaluated for crown rot resistance at seedling stage under greenhouse conditions. The results showed that 84% of tested accessions were susceptible, including many widespread varieties that are deploying in farming practice. That implied a potential of the increasing incidence and degree of crown rot in China in future. Fifteen genotypes showed reliable moderate disease resistance as the resistant control Sunco in multiple rounds of selection, with an average disease index ranged from 10.9 to 19.4. Specifically to these 15 genotypes, a variation on plant height and heading time was observed. Thus, this study unlocked the diseased index of Fusarium crown rot in Chinese wheat cultivars, which will provide reference for wheat resistance breeding.
2020, 21(2):314-320. DOI: 10.13430/j.cnki.jpgr.20190621002
Abstract:The axillary bud on cane stalk is the main reproductive organ for sugarcane vegetative reproduction. To ensure enough bud setts at planting is an essential prerequisite for high and stable cane yield, but too large bud setts also mean high planting cost. This is a common dilemma in sugarcane production. In previous studies on innovative utilization of hybrid from Saccharum robustum Brandes and Jeswiet ex Grassl, one mutant with double axillary buds (YZ07-86) was exploited. In this study, the twin axillary buds phenotypic frequency, stability, hereditability and its yield impact were determined. The double axillary buds were found to be randomly inserted from the 6 th stem node above ground to stem tip in three ways (twins, adjoined and separated), with an overall tendency of increasing first and then decreasing. Importantly, both of the double axillary buds are generally able to germinate after planting. Under a test of field-conditional asexual reproduction over years, the double axillary buds was found to be stably inherited in the population. By making crosses with 32 different sugarcane varieties, a few of progeny individuals with the double axillary buds was observed from 11 hybridization combinations. That suggested that the trait of double axillary buds was able to be transmitted by hybridization to the progeny with a very low frequency. In the yield comparison test with same amount of buds but planting single or double axillary bud setts respectively, no significant difference in millable stalks and cane yield was observed, suggesting a significant applied potential with the mutant in the sugarcane seed market. This study could establish a foundation for the following research such as the mining for candidate genes of double axillary buds and the practical use in sugarcane breeding.
2020, 21(2):321-329. DOI: 10.13430/j.cnki.jpgr.20190627003
Abstract:To study stalk characteristics and diversity of different main groups on maize in China is an important step for harvesting maize by mechanical means. In this study, seventy common maize inbred lines, derived from five groups of Lancaster, PB, Sipingtou, Lüda Red Cob and Reid respectively, were using to investigate their stalk-related traits, i.e. stem height (SH), ear height (EH), ear position coefficient (EPC), stem node number (SN), ear node (EN), ear node coefficient (ENC), internode length of ear (IL), internode diameter of ear (ID), stem fresh weight (FW), stem dry weight (DW), brix and moisture content (MC). A higher phenotypic variation existed in Sipingtou and Lüda Red Cob group, both of which are the local germplasms in China. At the filling stage, the moisture content of maize stalk became stable. A significant correlation in maize plant height and internode length was observed, while the number of internodes between ear and tassel was relatively constant. The sugar content of maize stalk was correlated to the length of internode, the diameter of stem and the location of ear. It’s more effective through lowering ear locating node to reduce ear height. Furthermore, maize stalk exists distint characteristics among different groups. For examples, Lancaster group has less stem node, Reid group has greater internode diameter while PB group has less one, Lüda Red Cob group has greater internode diameter and less internode length, Sipingtou group has shorter stem, less brix and dry weight. There has strong heterosis of biomass and grain yield in Lancaster × Sipingtou and Lancaster × PB. It’s an alternative strategy of mechanization breeding utilizing China local germplasm with the longer internode and the lower ear node. These results could provide important reference for maize breeding.
2020, 21(2):330-337. DOI: 10.13430/j.cnki.jpgr.20190428003
Abstract:Sesame Fusarium wilt (SFW), which is caused by Fusarium oxysporum f. sp. sesami (FOS), is one of the main fungi diseases and primarily occurs at vegetative growth and flowering stages in sesame. In order to accurately evaluate the resistance level of sesame germplasm accessions to FOS strains during vegetative stage (from two-pair-leaves period to budding period), we analyzed the Fusarium wilt symptoms and the disease index (DI) variation of sesame germplasm accessions treated with several FOS strains, various concentrations of microconidia suspension and different time with treatment. A precise evaluation method of sesame resistance to Fusarium wilt disease during vegetative stage was established. Results indicated that Fusarium wilt symptom occurred in sesame plantlets 1 to 2 weeks later after inoculation with 1 × 106 microconidia/ mL FOS suspension. The DI values became stabilized after 4 weeks. The resistance level of germplasm accessions and the pathogenicity of FOS strains were reflected using the above established method. Five grades of Fusarium wilt resistance from grade 0 to 4 for sesame during vegetative stage was proposed. The results derived from tests of 42 sesame accessions revealed that the wild species, S. radiatum exhibited the stable high resistance to FOS (DI = 0), while S. angustifolium was highly susceptible (DI = 100). Of the 40 cultivated accessions, 57.5% samples were highlysusceptible (HS), while 27.5% were showing high- or medium-resistant. The findings supply the technological aids in further analyzing the genetic mechanism of sesame resistance to Fusarium wilt disease.
2020, 21(2):338-346. DOI: 10.13430/j.cnki.jpgr.20190625002
Abstract:Loose-curd cauliflower is currently the main type of cauliflower consumed in China. Clubroot and black spot diseases are improtant diseases that directly and adversely affect the yield and quality of cauliflower. Therefore, to select varieties of good commercial quality with high and multiple resistance is one of the major goals in cauliflower breeding. In this study, we for the first time established the evaluation system of curd traits for loose-curd cauliflower germplasm resources. Sixty-six accessions of loose-curd cauliflower inbred lines were evaluated for eight characters of curd compactness, curd shape, surface smoothness, surface color, buds size, length of secondary lateral branch, pedicel color and curd hairiness. Each character was assigned a value for statistics and comparison. Eleven inbred lines were selected for excellent traits based on the evaluation system. With artificial inoculation at seedling stage, we identified and evaluated the resistance to clubroot and black spot of loose-curd cauliflower respectively. The results showed that none of the accessions were immune to clubroot, with 2 of high resistance, 9 of fair resistance, 16 of medium resistance, and none of the accessions were immune or highly resistant to black spot, with 4 of fair resistance, 10 of medium resistance. Only a few accessions were found to have dual resistance to clubroot and black spot diseases. Among them, ‘GY-40’ showed relatively high resistance to both diseases, ‘GY-21’ showed fair resistance to clubroot and medium resistance to black spot, and ‘GY-21’ showed medium resistance to both diseases. ‘GY-40’ is therefore an ideal parent line for breeding cauliflower varieties, due to its excellent traits and relatively high dual resistance to both clubroot and black spot diseases. The study will provide reference for evaluating curd traits of cauliflower germplasm resources, be of great significance for standardization of resources collection, sorting and preservation, and provide excellent accessions for breeding of loose-curd cauliflower varieties with dual resistance to clubroot and black spot diseases.
2020, 21(2):347-358. DOI: 10.13430/j.cnki.jpgr.20190524004
Abstract:In order to establish the methods for DUS test in hosta (Hosta Tratt.), we investigated the phenotypic diversity at 19 quantitative traits in 76 varieties. The quantification period and tissue position for some phenotypic characters were analyzed. As a result, the width of petiole could be measured in its natural state, and the length of peduncle could be quantified from the base to the attach of first flower. The bracts of first flower were suitable as observation object for all characters of bract, and the 1st-3nd opening flower was optimal for quantitative traits about flower. All the candidate characters fulfilled the requirements of DUS testing and could be classified into 3 to 9 continuous grades. The characters in whole plants and the leaves could be measured at blossom, and the characters of inflorescence should be observed after the last flower opened.
2020, 21(2):359-368. DOI: 10.13430/j.cnki.jpgr.20190627002
Abstract:Heat-stabilized protein is an important index to measure the quality of malt. In order to explore the content of heat-stabilized protein, the composition characteristics of protein Z and the influencing conditions in barley grains and malt, three hulless barleys (Liulengzi changmang baiqingke, Qingpi qingke and 9820) and one hulled barley (Gairdner ) were used to analyze and identify the heat-stabilized protein of hulless barley grains and malt. Then the content of the heat-stabilized protein of hulless barley and the composition characteristics of protein Z were studied in different ecological environments. The barley lines with excellent brewing quality were selected. The results showed that the optimal barley germination conditions (20℃, 72h and PH 5) enabled the accumulation of heat-stabilized protein and protein Z in germination and kinling. The hulless barleys, which were planted and harvested at three locations (Xining, Huangyuan and Haiyan) with different climatic conditions, were tested for the content of grain. A lowest bud heat-stabilized protein, but the highest heat-stabilized protein and protein Z after kinling, were observed from the grains in Xining. Meanwhile, fifteen excellent resources with high content of heat-stable protein were identified by testing 150 hulless barley germplasm resources. Thus, the results gained from this study will provide theoretical basis in breeding for hulless malting barley varieties with the qualified indexes.
2020, 21(2):369-376. DOI: 10.13430/j.cnki.jpgr.20191028005
Abstract:To evaluate the kernel quality characteristics of the local sesame resources in Guizhou, eight quality-related traits of 73 Guizhou sesame accessions were analyzed. The oil content of sesame germplasms was ranged from 41.45% to 52.12%, with an average of 49.69%. The mean value of unsaturated fatty acids oleic acid and linoleic acid was 35.65% and 50.66%, respectively, while that of saturated fatty acids including palmitic acid and stearic acid was 8.40% and 4.79%, respectively. Furthermore, mean of three components sesamin, sesamolin and lignin in the tested sesame accessions were 5.03, 2.63 and 4.79 mg/g, respectively. The variation coefficient of these eight quality traits ranged from 3.69% to 32.62%, while the highest and lowest values were observed in sesamin and oil contents, respectively. Notably, the variation coefficient of sesamin content, sesamolin content and stearic acid content was more than 10%, which indicated that these three traits were significantly different among sesame samples. The correlation analysis showed that oil content was significantly positively correlated with oleic acid content and sesamin content. However, the oil content was significantly negatively correlated with linoleic acid content. Moreover, oleic acid content was positively correlated with the sesamin content, but negatively correlated with linoleic acid content. The linoleic acid content was negatively correlated with the sesamin content. By Principal component analysis (PCA), three principal components including oleic acid factor, oil content factor and sesamin factor explained 96.59% of the phenotypic variation. The cluster analysis roughly revealed six groups (Euclidean distance D = 9.75), which include 2, 12, 5, 16 and 31 accessions shared in Group Ⅰ, Ⅱ, Ⅲ, Ⅳ, Ⅴ and Ⅵ, respectively. The accessions resided in group Ⅵ contained the highest oleic acid and oil content as well as moderate sesamin content. Taken together, this study unlocked the quality-related characteristics of Guizhou sesame accessions, which could provide a theoretical basis and good references for utilization and innovation of sesame germplasms.
2020, 21(2):377-385. DOI: 10.13430/j.cnki.jpgr.20190625001
Abstract:Bitterness in melon (Cucumis melo L.) seriously affects fruit quality and marketability. The present study aimed to search for the molecular basis of bitterness in melon based on positive genetic strategy. An F2 segregating population was constructed using 100 individuals derived from a cross between the non-bitter female parent C69 and the bitter male parent C14. A genetic linkage map was constructed based on 2b-RAD sequencing, which was then combined with the phenotypic trait of fruit bitterness for QTL mapping and genome-wide association study, and a PAV was detected by the in-depth information of 2b-RAD sequencing. Key genes controlling fruit bitterness were determined by re-sequencing of the two parents. The F1 population showed strong bitterness in fruit, and the F2 population had 81 and 19 individuals with bitter and non-bitter fruit respectively, which approximated the 3:1 segregation ratio (?2=1.92，P=0.1659). A linkage map was constructed based on 477 SNPs distributed in 10 linkage groups. The total length of the linkage map was 337.79 cM, with an average distance of 0.71 cM between adjacent markers. Whole genome QTL mapping identified one QTL for bitterness, which explained 20% of the phenotypic variation on LG08 (corresponding to chromosome 9). Genome-wide association study detected seven SNPs significantly associated with bitterness in melon, which were located on the target QTL region for bitterness on chromosome 9. PAV analysis detected the presence or absence of a long fragment (from 21,707,702 bp to 21,743,072 bp on chromosome 9) in the QTL region, which explained the fruit bitterness or the lack of it in F2 population. The in-depth re-sequencing of the two parents were checked and it was found that the PAV region was larger, of about 62 kb, and was involved in nine consecutive genes (MELO3C005601, MELO3C005602, MELO3C005603, MELO3C005604, MELO3C005605, MELO3C005606, MELO3C005607, MELO3C005608 and MELO3C005609), of which five were cytochrome CYP450 genes. The constructed phylogenetic tree revealed that these five cytochrome P450 genes were in the same clade with the cytochrome P450 gene clusters CYP81Q58, CYP81Q59 and CYP712D8 involved in cucurbitacin C/B/E synthesis, and may function similarly. The phenotypes of F1 and F2 populations indicated that the fruit bitterness was controlled by one dominant gene in melon line C14. The PAV located in the QTL region co-segregated with the bitterness phenotype and explained 100% phenotypic variation in the F2 population, which suggested that the absence of the nine genes was the main cause for the non-bitterness of C69. The five cytochrome CYP450 genes are potentially part of the gene cluster of CuB biosynthesis pathway. Comparative analysis identified two bHLH transcriptional factors tightly linked with PAV in present study, which controlled the formation of CuB, CmBr (MELO3C005610) and CmBt (MELO3C005611) located in the consecutively linked regions in chromosome 9. The present results provide new theoretical support and target of molecular marker assisted breeding of melon.
2020, 21(2):386-393. DOI: 10.13430/j.cnki.jpgr.20190417001
Abstract:Wheat relatives-derived alien genes provide most important resource to develop resistant varieties and protect wheat from the damage of powdery mildew. Pm57, a gene resided on the long arm of chromosome 2Ss#1 from Aegilops searsii caused broad-spectrum resistance against powdery mildew isolates at seedling and adult plant stage. In order to develop Pm57 mutants with loss of resistance to powdery mildew for further gene isolation using susceptible mutant-based resistant cloning approache, 10000 seeds of 89(5)69, a wheat-Ae. searsii recombinant stock containing Pm57 genes,were treated using 0.625% Ethyl methane sulfonate (EMS). M1seeds were then dense sowed in experiment station, and 1598 M2 lines were harvested. Of which 300 M2 lines randomly selected were used for resistance test by inoculation at seedling stage. After further validation of susceptible individual plants using two Pm57 specific molecular markers (X2L4g9P4/HaeIII and X284274) and 42 pairs of core primers,which are applied in DUS identification of wheat lines, 70 Pm57 mutants with loss of resistance to powdery mildew from 27 independent M2 lines were identified, with a mutant ratio as high as 9.0%. Thus, the newly-identified resistance-compromised mutants might lay a foundation for further cloning of the Pm57 gene.
2020, 21(2):394-401. DOI: 10.13430/j.cnki.jpgr.20190611004
Abstract:The abundant genetic diversity provides a broad genetic basis for soybean breeding. Based on 35 pairs of SSR markers, the genetic diversity of 60 soybeans being resistant to Phytophthora Root Rot in Northeast China was analyzed. A total of 189 alleles were detected, with an average of 5.4 alleles per locus. The polymorphism information content index (PIC) was variable from 0.1550 to 0.8195 with an average of 0.6636. The genetic similarity coefficient varies from 0.31 to 0.74. The fingerprint map in each of resistant varieties was constructed using 5 pairs of highly polymorphic SSR primers. Using NTSYS2.10 clustering analysis based on genetic distance, sixty resistant genotypes were divided into 7 groups, of which 78.33% of resistant varieties (lines) had a similarity coefficient between 0.45 and 0.74. That indicated a relatively narrow genetic difference among these resistance-conferring genotypes. The results of cluster analysis and population genetic structure analysis partially overlap, suggesting the existence of multiple penetration and communication events between resistant materials in different regions.
2020, 21(2):402-408. DOI: 10.13430/j.cnki.jpgr.20190425002
Abstract:Tartary buckwheat is one of minor grain crops in China, which has rich nutrition and is an important source of natural rutin. It is an important aspect of present research to break through of breeding and create new germplasm in tartary buckwheat. The mutation library was constructed in “Heifengyihao” by EMS. The half lethal treatment of EMS mutagenesis was 1.2%, the effect of plentiful phenotype was recorded in M1 generation. 102 plants with obvious phenotypic variation, including leaf color, leaf shape, plant type and grain sizes, were obtained from M3 materials and the mutation rate was 3.85%. The rutin content of 1000 plants in mutants’ library was determined by HPLC, 2 mutant lines with high (rutin content >16 mg/g) and 5 lines of low rutin (rutin content <10 mg/g) were obtained respectively. Comparison of rutin synthesis-related genes through qRT-PCR showed a relative weaker relationship between FtCHS, FtF3H, Ft4CL, FtUFGT transcripts and rutin content mutation lines. However, it also found that FtFLS showed the higher expression level in line with higher rutin content, which reached 4.55 times of control. The screening of mutants enriched the resources of tartary buckwheat, innovated the new germplasm of tartary buckwheat, and provided material guarantee and technical support for the molecular basis research of tartary buckwheat metabolism.
2020, 21(2):409-417. DOI: 10.13430/j.cnki.jpgr.20190527003
Abstract:The objective of this study is to determine the potential resistance genes in wheat landraces and provide reference information for the selection and utilization of leaf rust resistance resources. In this study, 15 wheat landraces, susceptible control Zhengzhou 5389 and 36 resistance donor lines were tested for leaf rust resistance. The genotypes were tested in the greenhouse to 19 Puccinia triticina pathotypes for a seedling resistance, and in the field to a mixed pathotypes for slow rusting resistance in two cropping seasons (2016-2017 and 2017-2018) in Baoding, Hebei Province. Meanwhile, twelve molecular markers targeting the resistance loci were used for genotyping in wheat cultivars. Resulted from the resistance spectra and marker analysis, seven leaf rust resistance genes were detected in 15 landraces. For instance, the landrace Honggoudou may contain both Lr1 and Lr46; Huanghuamai may have both Lr13 and Lr34; Dabaimai may carry Lr14b and Lr26; Yangmai may carry Lr37 and Lr46; Chengduguangtou may carry Lr34 and Lr46. Two resistance genes Lr26 and Lr46 were found to be present in genotypes Motuomai and Xishanbiansui. Furthermore, the slowing rust resistance gene Lr34 was detected in Tongjiabaxiaomai, Wudubaijianer, Bianbachunmai-6 and Baihuamai, while another partial resistance gene Lr46 was detected in Hongqiangmai, Baibiansui and Baihuomai. These genotypes effective against leaf rust might provide resistance genes for disease-resistant breeding in hexaploid wheat.
2020, 21(2):418-430. DOI: 10.13430/j.cnki.jpgr.20190414003
Abstract:In order to identify new resistant resources of 156 exotic rice germplasm accessions for breeding in Fujian Province, test for rice blast resistance was conducted at two calendar years in experimental plot in Shanghang, Fujian. Genotypes carrying any of rice blast resistance genes Pi2, Pi9, Pi5, Pi54, Pikm, Pita, Pia and Pib were detected by molecular selection markers. As a result, 10, 14, 29 and 26 accessions showed resistant tseedling blast, leaf blast, neck blast and comprehensive resistance, respectively. Furthermore, the correlation analysis suggested significant positive correlations between seedling blast and leaf blast (r = 0.816, P < 0.01), seedling blast and neck blast (r = 0.347, P < 0.01), and leaf blast and neck blast (r = 0.344, P < 0.01). Marker assisted selection indicated 1, 6, 20, 22, 37, 88, 101 and 106 rice accessions, which harbored the resistance genes Pi9, Pi2, Pi54, Pikm, Pi5, Pib, Pia and Pita, respectively. 60% of accessions containing either of Pi9 and Pi2 genes were resistant to rice blast. A subset of rice accessions was found with stacking of 0 to 6 blast resistance genes. An elevation on rice blast resistance was observed if several resistance genes were present in an accession. For example, a combination of resistance genes Pi9+Pi5+Pikm+Pia, Pi5+Pib+Pita+Pikm+Pia and Pi2+Pi54+Pib+Pita+Pikm+Pia displayed the better resistance. Finally, 8 rice blast resistant genotypes were identified with potential for rice breeding.
2020, 21(2):431-441. DOI: 10.13430/j.cnki.jpgr.20190509001
Abstract:To screen the single nucleotide polymorphism (SNP) loci and candidate genes associated with low-phosphorus stress in wheat, genome-wide association study (GWAS) of low-phosphorus related traits in common wheat was performed for understanding the genetic mechanism of low-phosphorus tolerance. In the study, 198 wheat varieties (lines) originated from the Huang-Huai area were used as test materials to evaluate the related traits in low phosphorus and normal phosphorus solution cultures. The wheat 35K Chip with 11896 SNP markers which were distributed in the whole genome of wheat were used to analyze the related traits of low-phosphorus tolerance. The mixed model of Q+K was chosen to determine the statistical associations between phenotypes and genotypes to evaluate the effects of population structure and related traits. The result showed that the low-phosphorus tolerance character of wheat had a wide range of phenotypic variation with the coefficient variation between 15.65% and 26.59%. The polymorphism information content (PIC) was between 0.095 and 0.500. Population structure analysis showed that the natural population in the experiment could be divided into two subgroups. GWAS analysis indicated that 67 SNP loci were significantly associated with low-phosphorus tolerance (p ≤ 0.001), which were located in 18 chromosomes except 3A, 3B and 3D chromosomes. Each SNP could explain 5.826% - 9.552% of phenotypic variation. Four SNP sites were simultaneously associated with 2 different low-phosphorus tolerance traits in these significant sites. Seven candidate genes may be related to the low-phosphorus tolerance of wheat through analysis of the 67 SNP sites. TraesCS6A02G001000 and TraesCS6A02G001100 play important roles in the synthesis of zinc finger. TraesCS6A02G118100 may be induced by low-phosphorus stress. TraesCS5D02G536400, TraesCS1B02G154200 and TraesCS5D02G536500 are related to the family of low-phosphorus stress-related enzymes. TraesCS1D02G231200 is related to DUF538 and its product can be a putative candidate for common stress-related protein in plant.
2020, 21(2):442-451. DOI: 10.13430/j.cnki.jpgr.20190627004
Abstract:Within this study, a QTL mapping of salt tolerance was conducted by using a population of chromosome segment substitution lines (CSSLs), which were generated from common wild rice as donor parent and cultivated rice (9311) as receive parent. Genotyping for CSSLs were performed with types of markers (SSR, InDel and genotyping-by-sequencing markers). The phenotypic datasets were assessed by systemically evaluating the salt tolerance at different growth periods. As a result, two QTLs at germination stage and 13 QTLs at seedling stage were obtained. Among QTLs, qSSR5.1 and qSSG5.1 were found at the same locus, which synergistically contributed to the seedling survival rate (6.36%) and salt tolerance grade (8.13%). Within the target interval, one candidate gene OsDi19-1 which associated with abiotic stress was found. Sequence alignment showed an obvious sequence variation between 9311 and wild rice in the promoter region of OsDi19-1. Notably, the line CSSL72 showed a higher germination rate, while CSSL23 and CSSL153 exhibited higher seedling rates. A down-regulation on gene expression was observed in CSSL23 and CSSL153, if relative to 9311 under salt treatment. Taken together, our data indicated that OsDi19-1 from wild rice might contribute to the salt tolerance, and these elite lines might become useful in future rice salt tolerance breeding.
2020, 21(2):452-458. DOI: 10.13430/j.cnki.jpgr.20190611002
Abstract:Leaf-color mutants are important materials for deciphering the photosynthesis and chloroplast development. In this study, a yellow-green leaf mutant was identified and designated ygl-F17138. By making a cross with the maize inbred line B73, we constructed a F2 segregation population for the genetic analysis and the preliminary gene mapping. Genetic analysis indicated that this yellow-green phenotype was genetically controlled by a recessive nuclear gene. By deployment of BSR-seq and the linkage analysis method, this gene was allocated to an interval of about 9.2 Mb on chromosome 3 (chr3: 173087201-182203992). According to the functional annotation of known genes in this interval, no genes which regulating yellow green leaf traits similar to those previously reported were found, indicating that YGL-F17138 gene is a candidate gene controlling yellow green leaf in maize.
2020, 21(2):459-465. DOI: 10.13430/j.cnki.jpgr.20190523001
Abstract:Under salt stress from the soil, the economic yield of wheat will decrease due to reduced uptake of water and nutrients. The enhancement of root tolerance to salt will be one of the important ways in wheat breeding for salt-tolerance. It will significantly raise root salt-tolerance by driving salt-tolerance genes preferentially expressed in roots, greatly induced by salt stress, while isolation and characterization of the promoter with dual functions will be the basis of precise control of salt-tolerance genes. Hence, in this study, we screened and determined 425 probes, and selected 2 candidate probes from them for further promoter validation. The roots of one-week-old seedlings of wheat variety ‘Chinese Spring’ were placed in 200 mM NaCl solution, and sampled at 0 h, 0.5 h, 1 h, 2 h, 4 h and 8 h for analysis of gene expression patterns. The results showed that the gene corresponding to Ta.5463.1.A1_at probe was fitting better into the expected bioinformatic results, which is preferentially expressed in roots and up-regulated by the induction of salt stress. To further verify the functions of its promoter, the promoter region was cloned and ligated into the promoter verification vector, and transgenic Arabidopsis plants were obtained. The results of salt induction and GUS staining showed that the promoter could regulate the expression of GUS reporter gene under salt treatment significantly, and the reporter gene was mainly expressed in roots. Our study successfully isolated specific promoter for salt tolerance, and provided an excellent resource for molecular breeding in wheat stress resistance.
2020, 21(2):466-476. DOI: 10.13430/j.cnki.jpgr.20190506001
Abstract:In order to investigate the characteristics of S. robustum Ty1-copia retrotransposon reverse transcriptase (RT), the Ty1-copia RT sequences were isolated by PCR amplification with universal primers. Sixty Ty1-copia RT sequences were successfully isolated with a length of 233 to 266 bp. Through ClustalX software analysis, several conserved domains in the amino acid sequences were revealed, such as TAFLHG, YVDDM and SLYGLKQ, which were found at the upstream, downstream and central parts, respectively. Several frameshift mutation in the code reading box and at the termination codon mutation were found. The phylogenetic tree analysis of Ty1-copia RT sequences of S. robustum and other Gramineae species suggested eight different evolutionary lineages. 20 % of S. robustum Ty1-copia RT amino acid sequences were classified as class I (Sre / Maximus), 16.7 % were classified as Class II (Retrofit / Ale), 30 % were classified as Class III (Ale), 28.3 % were classified as Class VIII (Tork / TAR), and 5 % of the sequences were classified as Class V (Tork) / Angela). This analysis indicated that S. robustum was closely related to the Saccharum spp. hybrid and Sorghum. Based on the result of dot blot hybridization, the copy number of the S. robustum Ty1-copia RT sequence was calculated to be 6.75×103 in one genome. The FISH results showed that the S. robustum Ty1-copia RT sequences were distributed on the chromosome, which the signal of telomere region was stronger than other regions in some chromosomes. These results would provide a reference for the biodiversity study and genome research of S. robustum in the future.
2020, 21(2):477-482. DOI: 10.13430/j.cnki.jpgr.20190604001
Abstract:With the increase of crop germplasm resources, the increasingly frequent exchange of germplasm resources and the gradual deepening of the utilization of germplasm resources, the construction of crop germplasm resources database is very important for the application research and basic research of crops. Shanghai Agricultural Biological Gene Center has developed a set of Shanghai crop germplasm resources database，based on the information of nearly 210000 crop germplasm preserved by the Center. This paper mainly describes the purpose and principle of the database design and construction, architecture of the database, running environment and main function modules..The database of Shanghai Crop Germplasm Resources inadopts B/S structure, and the platform system realizes the collection, storage, query, statistical analysis and other functions of crop germplasm resources data using multi-layer logical structure. External users can access the platform system through browser, browse and query germplasm resources information. The internal administrator can use the limited function of the platform and manage the whole platform data, when the authentication is successful. Registered users can also submit the introduction application through the gene resource database, and administrators can carry out network management for the whole process of external supply. This can improve work efficiency and increase the transparency of workflow.
2020, 21(2):483-490. DOI: 10.13430/j.cnki.jpgr.20190505002
Abstract:Unmanned aerial vehicle (UAV) near-air remote sensing technology provides the accessibility to monitor the farmland in a rapid and real-time manner. By taking use of the UAV visible light remote sensing platform, here the aerial images of canopy using 26 ramie germplasms were generated and analyzed for the characteristic values using the image processing pipeline. The results showed that HSV color image segmentation can effectively recognize ramie from soil weeds. The variation coefficient at 6 phenotypic traits of 26 ramie resources was 11.00%-52.39%, and the diversity index was 0.62-1.58. The variation coefficients of 15 canopy color and texture traits of 26 ramie resources were distributed between 0.28% and 48.09%, and the diversity index was ranged from 1.25 to 1.54. That indicated a broad phenotypic variation in the tested ramie germplasm resources. Two principal components were identified by principal component analysis of 15 canopy color and texture traits, and the cumulative contribution rate reached 95.10%, which can effectively reflect the main information of each trait.
2020, 21(2):491-499. DOI: 10.13430/j.cnki.jpgr.20190528002
Abstract:CIPK (CBL-interacting protein kinase) is a serine / threonine protein kinase which plays an important role in response to stress in plants. In this study, MsCIPK8 was obtained by using RT-PCR based on transcriptional analysis of alfalfa in response to saline-alkaline stress. Sequence analysis of MsCIPK8 showed a 1341 bp CDS encoding 446 amino acids with a relative molecular mass of 50.73 kDa and an isoelectric point of 6.72. MsCIPK8 performed an N-terminal kinase domain and a C-terminal NAF/FISL domain as a CIPKS family protein. Bioinformatics analysis indicated that MsCIPK8 is a soluble protein with a high proportion of random coil in secondary structure. Phylogenetic analysis showed that MsCIPK8 was most closely related to MtCIPK8 (Medicago truncatula).Four difference sites were found in the two protein sequence alignment, of which 3 were in the conserved domain. MsCIPK8 had induced high expression in response to low temperature, drought, salt and salt-alkali. The expression of MsCIPK8 in roots and leaves had the highest transcript abundance at 12 h and 3 h under low temperature stress respectively. Under saline stress, the highest expression level of MsCIPK8 in roots was detected at 12 h. Under saline-alkaline stress, the expression of MsCIPK8 in roots and leaves remained high after 12 h. Under drought stress, the expression of MsCIPK8 in roots and leaves reached the highest expression level at 12 h. These results indicated that the expression of MsCIPK8 might be related to the resistance of alfalfa to abiotic stresses such as drought, low temperature, salt and salt-alkali.
2020, 21(2):500-506. DOI: 10.13430/j.cnki.jpgr.20190507003
Abstract:This study aims to clone the FmJZ1 gene and clarify its response model under low temperature and NaCl stresses and its hormone-induced transcriptional expression characteristics . The FmJAZ1 gene of Fraxinus mandshurica was obtained by gene cloning. The sequence was analyzed by bioinformatics software and phylogenetic tree was constructed.Spatiotemporal expression specificity of Fraxinus mandshurica FmJAZ1 gene was analyzed. Samples of root, stem, leaf, bud, male flower, female flower and seedwere taken in May, June, July, August, and September respectively for plants of Fraxinus mandshurica under low temperature stress (4℃) salt stress (NaCl solution), or treated with hormone signal induction of abscisic acid (ABA), gibberellin (GA3), auxin (IAA), jasmonate (JA), and salicylic acid (SA), The treated materials were then subjected to fluorescence quantitative analysis,The full length nucleotide sequence of 684 bp was cloned in this experiment, Bioinformatics software analysis showed that JZA1 gene had a complete open reading frame, encoding 227 amino acids. JAZ1 protein did not contain signal peptide, it was not a transmembrane protein, and it was an unstable hydrophilic protein. The spatial expression of FmJAZ1 gene was the highest in stem, and the temporal expression was the highest in August. The expression level of FmJAZ1 gene was higher at 6 h and 24 h after low temperature treatment. and higher 24 h after NaCl treatment, with the response to low temperature stress faster than that to salt stress. The expression level of FmJAZ1 gene changed significantly with time after the treatments hormone signal induction, and the expression pattern of FmJAZ1 gene was analyzed for low temperature, NaCl stress and hormone induction treatments. The expression change of FmJAZ1 gene was 77.3 times higher than that of control group at 3 h after GA3 treatment. FmJAZ1 gene fully responded to abiotic stresses and hormone signal induction, with JAZ protein acting as a bridge and playing an important role in the responses at protein and gene levels.