玉米叶片叶绿素含量的全基因组关联性分析

Genome-wide Association Study of Chlorophyll Content in Maize Leaves

植物叶片的叶绿素含量与叶片的光合作用效率和产量潜力紧密相关,因此是作物的一个重要生理指标。但是,目前已克隆的控制叶绿素含量的基因大多来自拟南芥和水稻,尚不清楚玉米自然群体中哪些基因控制叶片叶绿素含量的变异。本研究发现玉米苗期第一片叶片的叶绿素含量和吐丝期穗位叶的叶绿素含量高度相关,且与后者相比具有更高的遗传力。进一步分析了287份玉米自交系的第一片叶的叶绿素含量,利用558 269个单核苷酸多态性分子标记进行全基因组关联性分析,获得9个显著关联SNP位点和16个候选基因。通过候选基因的序列分析和功能预测,发现两个可能和叶绿素含量相关的基因,包括拟南芥Tic22基因的同源基因和水稻衰老相关基因SAG12的同源基因。

The chlorophyll content of plant leaves is closely related to photosynthetic efficiency and yield potential, thus it is an important physiological indicator of all crop species. However, currently most cloned genes controlling chlorophyll content are fromArabidopsis and rice, and the genetic basis of natural variation in chlorophyll content in maize is still unclear. In this research it was discovered that the chlorophyll content of the first leaves at the seedling stage was highly correlated with that of ear leaves at silking stage, and the former had a higher heritability than the latter. This study further analyzed the chlorophyll contents of first leaves from 287 maize inbred lines. Genome-wide association study using 558 269 SNP markers revealed 9 SNPs significantly associated with the measured trait, leading to the discovery of 16 candidate genes. Two genes potentially controlling chlorophyll content in maize were identified by sequence analysis and functional annotation of these candidate genes ： a homolog of the Arabidopsis Tic22 and a homolog of rice SAG12 relating to aging.