Background

Seed dormancy, a quality characteristic that plays a role in seed germination, seedling establishment and grain yield, is affected by multiple genes and environmental factors. The genetic and molecular mechanisms underlying seed dormancy in rice remain largely unknown.

Results

Quantitative trait loci (QTLs) for seed dormancy were identified in two different mapping populations, a chromosome segment substitution line (CSSL) and backcross inbred line (BIL) population, both derived from the same parents Nipponbare, a japonica cultivar with seed dormancy, and 9311, an indica cultivar lacking seed dormancy. A total of 12 and 27 QTL regions for seed dormancy were detected in the CSSLs and BILs, respectively. Among these regions, four major loci (qSD3.1, qSD3.2, qSD5.2 and qSD11.2) were commonly identified for multiple germination parameters associated with seed dormancy in both populations, with Nipponbare alleles delaying the seed germination percentage and decreasing germination uniformity. Two loci (qSD3.1 and qSD3.2) were individually validated in the near-isogenic lines containing the QTL of interest. The effect of qSD3.2 was further confirmed in a CSSL-derived F₂ population. Furthermore, both qSD3.1 and qSD3.2 were sensitive to abscisic acid and exhibited a significant epistatic interaction to increase seed dormancy.

Conclusions

Our results indicate that the integration of the developed CSSLs and BILs with high-density markers can provide a powerful tool for dissecting the genetic basis of seed dormancy in rice. Our findings regarding the major loci and their interactions with several promising candidate genes that are induced by abscisic acid and specifically expressed in the seeds will facilitate further gene discovery and a better understanding of the genetic and molecular mechanisms of seed dormancy for improving seed quality in rice breeding programs.

中文翻译：

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水稻（Oryza sativa L.）种子休眠的遗传剖析通过使用两个来自普通亲本的作图种群进行。

背景

种子休眠是一种受种子基因萌发，幼苗生长和籽粒产量影响的品质特征，受多种基因和环境因素的影响。水稻种子休眠的遗传和分子机制仍然未知。

结果

在两个不同的作图群体中鉴定了种子休眠的数量性状基因座（QTL），染色体片段替代系（CSSL）和回交自交系（BIL）群体，它们均来自相同的父母Nipponbare，具有种子休眠的粳稻品种，以及9311，一个籼稻品种缺乏种子休眠。在CSSL和BIL中分别检测到总共12个和27个QTL种子休眠区域。在这些区域中，有四个主要基因座（qSD3.1，qSD3.2，qSD5.2和qSD11.2通常确定两个种群中与种子休眠相关的多个发芽参数，Nipponbare等位基因延迟了种子发芽率并降低了发芽均匀度。在包含目的QTL的近等基因系中分别验证了两个基因座（qSD3.1和qSD3.2）。的效果qSD3.2在CSSL-F衍生进一步证实₂群体。此外，qSD3.1和qSD3.2都对脱落酸敏感，并且表现出显着的上位性相互作用以增加种子休眠。

结论

我们的结果表明，已开发的CSSLs和BIL与高密度标记的整合可以为剖析水稻种子休眠的遗传基础提供强大的工具。我们关于主要位点及其与脱落酸诱导并在种子中特异性表达的几个有前途的候选基因的相互作用的发现，将有助于进一步的基因发现，并更好地理解种子休眠的遗传和分子机制，从而改善水稻的种子质量。繁殖计划。