直播水稻茎鞘非结构碳水化合物积累与转运的遗传剖析

为了揭示水稻(Oryza sativa)茎鞘非结构碳水化合物(nonstructural carbohydrate, NSC)积累与转运的遗传基础, 在大田直播条件下, 利用来源于Lemont/特青的重组自交系群体, 对5个相关性状进行了QTL定位。始穗期和成熟期共检测到3个茎鞘NSC含量QTL, 分别位于第1、9和12染色体上, 贡献率分别为13%、7%和7%, 增效等位基因均来自特青。检测到的2个NSC转运率QTL均位于第12染色体上, 贡献率分别为8%和14%。检测到的结实率和千粒重QTL分别为3个和4个, 3个结实率QTL的贡献率分别为9%、24%和6%, 4个千粒重QTL的贡献率分别为14%、11%、12%和13%。进一步的分析表明,来自Lemont的等位基因降低成熟期茎鞘NSC含量的同时却能提高NSC转运率、结实率和千粒重, 而来自特青的等位基因对NSC转运率和结实率均有增效作用, 这为性状间表型相关提供了重要的遗传解释。

Genetic Dissection of Nonstructural Carbohydrate Accumulation and Translocation in Rice Culms and Leaf Sheaths Under Direct Sowing

We aimed to understand the genetic basis of nonstructural carbohydrate(NSC) accumulation and translocation in rice culms and leaf sheaths. Quantitative trait loci (QTL) for 5 related traits were mapped with use of a recombinant inbred line derived from a cross between Lemont (japonica var.) and Teqing (indica var.) under direct sowing. Three QTL affecting NSC content at heading and maturity were detected on chromosomes 1, 9 and 12, explaining 13%, 7% and 7%, respectively, of the phenotypic variation. The Teqing alleles increased the trait value at all three QTL. Two QTL for NSC translocation rate were identified on chromosome 12 and accounted for 8% and 14%, respectively, of the total variation.The number of QTL for seed-setting rate and 1000-grain weight were 3 and 4, respectively. The amount of variation explained by the seed-setting rate QTL were 9%, 24% and 6%, and that explained by the 1000-grain weight QTL were 14%, 11%, 12% and 13%. The Lemont allele decreased NSC content at maturity but increased NSC translocation rate, seed-setting rate and 1000-grain weight at the region near RM277 on chromosome 12. The Teqing allele increased both NSC translocation rate and seed-setting rate at the region near OSR20 on chromosome 12, which provides a genetic explanation for the close correlations among the traits.