水稻白穗调控基因WP4的图位克隆与功能分析OA

Leaf morphology and color in rice influence grain yield by regulating canopy photosynthesis and also contribute to tolerance to both biotic and abiotic stresses.In our previous study,we identified the pale-green leaf and white-hull mutant wp4(white panicle 4)and fine-mapped it to an approximately 79-kb region on chromosome 8.Here,sequencing of the candidate genes revealed a G-to-A substitution at the exon-intron junction of LOC_Os08g06280/LSD1,resulting in incomplete splicing of the fourth intron.Complementation assays confirmed that LOC_Os08g06280 corresponds to WP4.Introduction of the wild-type ge-nomic sequence of LOC_Os08g06280 into the wp4 restored leaf and hull color as well as photosynthetic pigment content,demon-strating that wp4 is a novel allele of lsd1.WP4 encodes a conserved plant-specific transcription factor containing three zinc-finger domains,and this protein exhibits high conservation with homologous genes across diverse species.RT-qPCR analysis showed that the expression of genes associated with chloroplast development,chlorophyll and carotenoid biosynthesis,and photosynthesis were downregulated in wp4.Together,these results highlight the essential role of WP4 in chloroplast development and chlorophyll synthesis.This work lays a foundation for further investigation of the regulatory mechanisms underlying WP4 function and pro-vides a valuable genetic resource for improving photosynthetic efficiency in rice breeding.