小麦GMP含量发育动态的QTL定位

QTL Mapping for Developmental Behavior of GMP Content in Wheat

利用小麦京771和Pm97034杂交后代重组自交系(RIL)群体,对小麦谷蛋白大聚合体(GMP)含量发育动态进行了QTL定位研究。结果表明,在籽粒灌浆的5个不同时期,共检测到8个条件QTL和10个非条件QTL,但没有一个QTL能在测定的5个时期都有效应。花后12 d,控制GMP形成的基因就已经有了一定的表达量,条件QTL能解释6.21%的表型变异,该基因位于1A染色体上。花后17 d,在1D染色体上测到了1个新表达的条件QTL位点,单独能解释14.14%的表型变异。花后22 d,控制GMP形成的基因的表达比较活跃,非条件分析检测到3个QTL位点,条件分析检测到2个QTL位点,这5个QTL位点分别位于1B、5B6、B和7B染色体上,其效应值都比较低,2个条件QTL共同能解释12.67%的净表型变异。花后27 d,在2D和3B染色体上各检测到2个条件和非条件QTL位点,加性效应值比较大。条件QTL能解释16.37%的表型变异,非条件QTL能解释23.94%的变异。花后32 d,仍有2个新的基因位点在表达,但此时QTL的净表达量已经开始下降,条件QTL仅能解释11.43%的表型变异。

Glutenin macropolymer （GMP） content is a key factor influencing wheat processing quality, which is determined by quantitative trait locus （QTL）. To date many QTLs related to quality characteristics, including the GMP content, have been mapped on wheat chromosomes. However, these researches were all focused on gene expression at a certain developmental stage, and could gave little information to understand the dynamic effects of corresponding QTLs at different developmental stages as well as the directions of gene action. In the present paper, QTL mapping for developmental behavior of wheat GMP content was studied, using recombinant inbred lines （RIL） population derived from Jing 771 x Pm97034. The results showed that eight conditional QTLs and ten unconditional QTLs were detected in different seed filling periods totally, but no one was detected in all periods. Each of these genes expressed in a special period. The additive effects of a conditional QTL located on chromosome 1A could be detected 12 days after anthesis, which could account for 6.21% of phenotypic variation in GMP content. A new conditional QTL was detected 17 days after anthesis, accounting for 14.14% of phenotypic variation. At the period of 17-22 days after anthesis the gene expression was active, and three unconditional QTLs and the two conditional QTLs were detected to be located on chromosome 1B, 5B, 6B and 7B with smaller additive effects, and the general contribution rate of the two conditional QTLs was 12.67 %. Four QTLs located on chromosome 2D and 3B were detected 27 days after anthesis with larger additive effects, in which the two conditional QTLs accounted for 16.37 % of phenotypic variation, while the other two unconditional QTLs accounted for 23.94% . Up to 32 days after anthesis, there still two new expressed genes were detected, but the net genetic variation declined, and conditional QTL just explained 11.43 % of phenotypic variation.