scholarly journals Identification of QTLs for Heat Tolerance at Flowering Stage Using Chromosome Segment Substitution Lines in Rice

2021 ◽  
Author(s):  
Thanhliem Nguyen ◽  
Shijie Shen ◽  
Mengyao Cheng ◽  
Chen Qingquan
Keyword(s):  
High Temperature ◽  
Heat Tolerance ◽  
Genetic Basis ◽  
Chromosome Segment ◽  
Seed Setting ◽  
Substitution Lines ◽  
Chromosome Segment Substitution Lines ◽  
Heat Tolerant ◽  
Segment Substitution ◽  
Heading Stage

Abstract High temperature is a major stress in rice production. Although considerable progresses have been made on investigating heat tolerance (HT) in rice, the genetic basis of HT at heading stage remains largely unknown. In this study, a novel set of chromosome segment substitution lines (CSSLs) consisting of 113 lines derived from a heat-resistant indica variety N22 and a heat-sensitive indica variety 9311 was developed and used for the analysis of genetic basis of HT. The heat sensitivity index (HSI) calculated based on seed-setting rates under natural and high temperature environments was used to evaluate the influence of HT at rice heading stage. Totally, five QTLs associated with HT were detected based on seed-setting rate (SSR) evaluation; these were named qSSR6-1, qSSR7-1, qSSR8-1, qSSR9-1 and qSSR11-1 located on chromosomes 6, 7, 8, 9 and 11, respectively. Heat-tolerant alleles of the QTLs were all derived from N22. Among them, qSSR9-1 overlapped with QTLs identified previously, while the remaining QTLs were found novel. Especially, qSSR7-1 explained a high phenotypic variation of 26.35% with a LOD score of 10.75, thus deserved to be further validated. These findings will increase our understanding of the genetic mechanism underlying HT and facilitate the breeding of heat-tolerant rice varieties.

scholarly journals Identification of a novel QTL and candidate gene associated with grain size using chromosome segment substitution lines in rice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Dianwen Wang ◽  
Wenqiang Sun ◽  
Zhiyang Yuan ◽  
Qiang Sun ◽  
Kai Fan ◽  
...  
Keyword(s):  
Grain Size ◽  
Grain Yield ◽  
Genetic Basis ◽  
Grain Weight ◽  
Chromosome Segment ◽  
Thousand Grain Weight ◽  
Substitution Lines ◽  
Grain Length ◽  
Chromosome Segment Substitution Lines ◽  
Segment Substitution

AbstractRice is one of the staple crops in the world. Grain size is an important determinant of rice grain yield, but the genetic basis of the grain size remains unclear. Here, we report a set of chromosome segment substitution lines (CSSL) developed in the genetic background of the genome-sequenced indica cultivar Zhenshan 97. Genotyping of the CSSLs by single nucleotide polymorphism array shows that most carry only one or two segments introduced from the genome-sequenced japonica cultivar Nipponbare. Using this population and the high-density markers, a total of 43 quantitative trait loci were identified for seven panicle- and grain-related traits. Among these loci, the novel locus qGL11 for grain length and thousand-grain weight was validated in a CSSL-derived segregating population and finely mapped to a 25-kb region that contains an IAA-amido synthetase gene OsGH3.13, This gene exhibited a significant expression difference in the young panicle between the near-isogenic lines that carry the contrasting Zhenshan 97 and Nipponbare alleles at qGL11. Expression and sequence analyses suggest that this gene is the most likely candidate for qGL11. Furthermore, several OsGH3.13 mutants induced by a CRISPR/Cas9 approach in either japonica or indica exhibit an increased grain length and thousand-grain weight, thus enhancing the final grain yield per plant. These findings provide insights into the genetic basis of grain size for the improvement of yield potential in rice breeding programs.

scholarly journals Genetic Dissection of Seed Dormancy using Chromosome Segment Substitution Lines in Rice (Oryza sativa L.)

2020 ◽  
Vol 21 (4) ◽  
pp. 1344 ◽  
Author(s):  
Shaowen Yuan ◽  
Yuntong Wang ◽  
Chaopu Zhang ◽  
Hanzi He ◽  
Sibin Yu
Keyword(s):  
Seed Dormancy ◽  
Genetic Architecture ◽  
Oryza Sativa L ◽  
Expression Profiles ◽  
Chromosome Segment ◽  
Isogenic Line ◽  
Substitution Lines ◽  
Chromosome Segment Substitution Lines ◽  
Segment Substitution ◽  
Seed Dormancy And Germination

Timing of germination determines whether a new plant life cycle can be initiated; therefore, appropriate dormancy and rapid germination under diverse environmental conditions are the most important features for a seed. However, the genetic architecture of seed dormancy and germination behavior remains largely elusive. In the present study, a linkage analysis for seed dormancy and germination behavior was conducted using a set of 146 chromosome segment substitution lines (CSSLs), of which each carries a single or a few chromosomal segments of Nipponbare (NIP) in the background of Zhenshan 97 (ZS97). A total of 36 quantitative trait loci (QTLs) for six germination parameters were identified. Among them, qDOM3.1 was validated as a major QTL for seed dormancy in a segregation population derived from the qDOM3.1 near-isogenic line, and further delimited into a genomic region of 90 kb on chromosome 3. Based on genetic analysis and gene expression profiles, the candidate genes were restricted to eight genes, of which four were responsive to the addition of abscisic acid (ABA). Among them, LOC_Os03g01540 was involved in the ABA signaling pathway to regulate seed dormancy. The results will facilitate cloning the major QTLs and understanding the genetic architecture for seed dormancy and germination in rice and other crops.

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