水稻黄叶少分蘖突变体yllt10的遗传与定位

Heredity and fine mapping of a yellow leaf and less tillering mutant yllt10 in rice

摘要:

水稻(Oryza sativa L.)是重要的粮食作物，其植株光合作用与肥料利用的效率是决定水稻产量的重要因素。本研究在水稻‘科辐粳7号’的辐射诱变群体中筛选到一个叶片黄化且分蘖减少的突变体，并将其命名为yllt10(yellow leaf and less tillering 10)。与野生型对照相比，该突变体叶片的叶绿素含量降低、叶绿体的结构发育异常、光合作用速率显著下降。遗传分析表明yllt10突变体的表型受单隐性核基因控制，利用图位克隆技术将YLLT10基因定位于水稻第10号染色体J4与J5两个分子标记之间，通过对该区间内的注释基因进行PCR测序，发现在yllt10突变体中CAO1/PGL基因的第1个外显子发生单碱基缺失，从而导致该基因的移码突变，是CAO1/PGL基因的一个新等位变异。此外，在不同氮素浓度种植条件下，yllt10突变体均表现出对氮素不敏感的表型。本研究表明YLLT10基因调控水稻的叶色和分蘖数，影响水稻的光合作用和产量，对该基因的功能机制研究能够为水稻高产育种提供一定的理论依据。

关键词:水稻突变体;叶片黄化;少分蘖;氮素响应

Abstract:

Rice (Oryza sativa L.) is a major food crop and increasing rice yield is the primary objective of rice research. Photosynthesis and nitrogen utilization efficiency directly affect the tiller number of rice, which affects the yield of rice. In this study, a stable yellow leaf and less tillering rice mutant yllt10 (yellow leaf and less tillering 10) was obtained by heavy-ion beam mutagenesis of rice variety ‘Ke-fu-geng 7’. Compared with the wild type, yllt10 showed reduced chlorophyll content, decreased photosynthesis rate, and abnormal chloroplast structure. The genetic analysis indicated that the phenotype of yllt10 was controlled by a single recessive nuclear gene. Map-based cloning localized YLLT10 between two molecular markers J4 and J5 on chromosome 10. The sequencing of candidate genes within this interval revealed that YLLT10 was an allelic mutation of CAO1/PGL with a single base deletion in the first exon resulting in the frame shift mutation of CAO1/PGL, and YLLT10 was a new allelic variation of CAO1/PGL. The mutant yllt10 was insensitive to changes in nitrogen concentration when being incubated with different nitrogen concentrations. YLLT10 controls leaf color and tiller number and affects photosynthesis and yield of rice. The study of this gene provides a theoretical basis for molecular breeding of rice.

Key words:rice mutant;leaf yellowing;less tillering;nitrogen response