基于水稻染色体片段代换系的苗期耐低氮QTL分析

贾佩陇; 李彪; 黎明辉; 刘剑镔; 李容柏; 罗继景

doi:10.7671/j.issn.1001-411X.201810046

基于水稻染色体片段代换系的苗期耐低氮QTL分析

QTL analysis of low nitrogen tolerance in rice seedlings based on chromosome segment substitution lines

摘要

摘要:
目的通过定位与水稻Oryza sativa耐低氮相关的数量性状位点(QTL)，为今后相关基因的精细定位、克隆以及功能研究奠定基础，也为耐低氮水稻品种的培育提供理论参考。

方法以Koshihikari (受体)和Nona Bokra (供体)为亲本构建的全基因组单片段代换系作为研究材料，在水稻苗期进行低氮胁迫处理，对水稻株高、根长、根鲜质量、根干质量、茎叶鲜质量、茎叶干质量、总鲜质量、总干质量共8个表型进行相对损失比分析和QTL定位。

结果定位到2个与水稻低氮胁迫耐受相关的位点，分别是qRL1-1和qRFW2-1，这2个QTL位点分别在低氮胁迫下控制水稻根长和根鲜质量。其中，qRL1-1定位于1号染色体M1-29标记附近，LOD值为2.89，可解释的表型变异为11.23%；qRFW2-1定位于2号染色体M2-225标记附近，LOD值为2.53，可解释的表型变异为9.90%。其他6个表型未检测到相关位点。

结论初步定位了与低氮胁迫下控制水稻根长、根鲜质量相关基因，为进一步的基因精细定位奠定基础。

Abstract:
Objective To map the quantitative trait loci (QTL) associated with low nitrogen tolerance in rice (Oryza sativa), provide a basis for future fine mapping, cloning and functional characterization of related genes and offer theoretical references for breeding of low nitrogen tolerant rice.

Method A set of chromosomal segment substitution lines which was constructed by crossing Koshihikari (recurrent parent) and Nona Bokra (donor parent) were used as test materials. Low nitrogen stress treatment was applied at rice seedling stage. The relative loss ratios of eight phenotypes including rice plant height, root length, root fresh weight, root dry weight, shoot fresh weight, shoot dry weight, total fresh weight and total dry weight were analyzed, and QTL mapping was performed.

Result Two loci related to low nitrogen tolerance of rice were successfully mapped. These two QTLs were qRL1-1 and qRFW2-1 which were related to root length and root fresh weight respectively under low nitrogen stress. qRL1-1 was closed to the M1-29 marker on chromosome 1 with a LOD score of 2.89 and explained about 11.23% of total phenotypic variance. qRFW2-1 was closed to the M2-225 marker on chromosome 2 with a LOD score of 2.53 and explained about 9.90% of total phenotypic variance. No loci was found for other six phenotypic indexes.

Conclusion QTLs related to root length and root fresh weight under low nitrogen stress are mapped, which lays the foundation for further genetic fine mapping and cloning of the underlying genes.

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