Analysis of QTLs for Mesocotyl Length in Rice (Oryza sativa L.)

The objective of this study was to understand the genetic basis underlying the relationship between mesocotyl elongation and plant hormone gibberellin (GA) in rice (Oryza sativa L.). Using a recombinant inbred line (RIL) population derived from a cross between 2 japonica rice cultivars, Shennong 265 (long mesocotyl) and Lijiang Xintuan Heigu (short mesocotyl), quantitative trait loci (QTLs) for mesocotyl length were detected under both water and GA germination conditions. The treatment of 1.50 μmol L−1 of GA dramatically stimulated the mesocotyl elongation of rice. A total of 5 QTLs for mesocotyl length were identified on chromosomes 1, 2, 3, 6, and 11 under water and GA germination conditions, which accounted for 7–33% of the phenotypic variance, respectively. The LOD value of each QTL ranged from 3.65 to 15.52. Among the 5 QTLs, qML3, qML6, and qML11 were common in both germination conditions, whereas qML1 and qML2 were detected only under water germination condition. qML3 was usually detected in several experiments using different populations, indicating that it might be a major QTL for mesocotyl elongation of rice.

摘 要为分析水稻中胚轴伸长与赤霉素的关系及其遗传基础, 以沈农265 (长中胚轴)和丽江新团黑谷(短中胚轴)的RIL群体为材料, 结合其连锁图谱, 对水和赤霉素溶液两种培养条件下的中胚轴长度进行QTL定位。结果表明, 浓度为1.50 μ;mol L−1的赤霉素可显著促进中胚轴的伸长。两种培养条件下, 共检测到控制中胚轴长度的5个QTL, 分布在第1、第2、第3、第6和第11号染色体上, LOD值在3.65∼15.52范围内, 单个QTL对表型贡献率在7%∼33%之间。其中qML3、qML6和qML11在2种处理条件下均被检测到, qML1和qML2仅在水培条件下被检测到。与其他研究比较发现, 主效基因qML3可以在不同群体和不同环境下稳定表达。