水稻黄绿叶突变体ygl209的遗传分析与目标基因精细定位

摘要

Etiolation mutants of rice play an important role in studies on the photosynthesis, chloroplast development, and chlo-rophyll metabolism in higher plants. Ajaponica rice mutantygl209 with yellow-green leaf was identified from the BC4F3 progeny of the cross between the transgenic variety of Zhongguo 91 and Zhendao 88 with the latter as the recurrent parent. Compared with the wild-type parent Zhendao 88, the contents of chlorophylla, chlorophyllb and carotenoid decreaseddramatically in the mutant ygl209at the seedling, tillering and heading stages, respectively. In particular, chlorophyllb decreased most significantly. How-ever, there was no significant change in other agronomic traits, such as heading stage, plant height, number of effective panicles per plant, number of grains in main stem panicle, seed setting rate and 1000-grain weight. Genetic analysis showed that the yel-low-green leaf trait of the ygl209 mutant was controlled by one pair of recessive nuclear genes. With F2 and F3segregation popu-lations derived from the cross betweenygl209 and Zhendao 88, theYGL209 gene was mapped to the centromere region of chro-mosome 1, with a physical distance of 571.6 kb. We further analyzed the putative candidate genes in the target region through sequencing. A single base substitution (G1390C) was detected in the coding region of theLOC_Os01g31110 gene, which resulted in a missense mutation (A348G) in its encoded protein. Bioinformatic analysis predicted that theLOC_Os01g31110gene is related to the chloroplast development in rice. Therefore,LOC_Os01g31110 is likely to be the candidate gene ofYGL209.%水稻叶色突变体是研究高等植物光合作用、叶绿体发育和叶绿素代谢的重要材料。从水稻转基因育种材料中国91与镇稻88的BC4F3后代中分离到稳定遗传的粳型黄绿叶突变体ygl209,与野生型亲本镇稻88相比,突变体ygl209在苗期、分蘖期及抽穗期叶片中叶绿素a、叶绿素b和类胡萝卜素含量均显著降低,其中叶绿素b降幅最大；其他农艺性状中抽穗期、株高、有效穗数、主茎穗总粒数、结实率和千粒重无显著变化。遗传分析表明, ygl209的黄绿叶突变性状由1对核隐性基因控制。应用(ygl209/9311) F2、F3分离群体,将ygl209的叶色突变基因定位于第1染色体着丝粒附近571.6 kb的染色体区段内。对区段内与叶绿体发育有关的基因LOC_Os01g31110序列测定,ygl209突变体中LOC_Os01g31110基因的编码区1390位(位于第5外显子)上碱基由C转换成 G,使编码蛋白序列由丙氨酸(Ala)变成了甘氨酸(Gly),推测LOC_Os01g31110即为ygl209的候选基因。