[Heredity and fine mapping of a yellow leaf and less tillering mutant <i>yllt10</i> in rice].

Rice (<i>Oryza sativa</i> 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 <i>yllt10</i> (<i>yellow leaf and less tillering 10</i>) was obtained by heavy-ion beam mutagenesis of rice variety 'Ke-fu-geng 7'. Compared with the wild type, <i>yllt10</i> showed reduced chlorophyll content, decreased photosynthesis rate, and abnormal chloroplast structure. The genetic analysis indicated that the phenotype of <i>yllt10</i> was controlled by a single recessive nuclear gene. Map-based cloning localized <i>YLLT10</i> between two molecular markers J4 and J5 on chromosome 10. The sequencing of candidate genes within this interval revealed that <i>YLLT10</i> was an allelic mutation of <i>CAO1/PGL</i> with a single base deletion in the first exon resulting in the frame shift mutation of <i>CAO1/PGL</i>, and <i>YLLT10</i> was a new allelic variation of <i>CAO1/PGL</i>. The mutant <i>yllt10</i> was insensitive to changes in nitrogen concentration when being incubated with different nitrogen concentrations. <i>YLLT10</i> 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.