Defective mitochondrial function by mutation in THICK ALEURONE 1 encoding a mitochondrion-targeted s

• 作 者: Dong-Qi Li Xiao-Ba Wu Hai-Feng Wang Xue Feng Shi-Juan Yan Sheng-Yang Wu Jin-Xin Liu Xue-Feng Yao Ai-Ning Bai Heng Zhao Xiu-Fen Song Lin Guo Shi-Yong Zhang Chun-Ming Liu
• 机 构: Key Laboratory of Plant Molecular Physiology,Institute of Botany,Chinese Academy of Sciences,Beijing
• 出 处: 分子植物（英文版）
• 发表日期: 2021年8期
• 关键词: rice thick aleurone cell-fate determination nutritional improvement mitochondria

Cereal endosperm comprises an outer aleurone and an inner starchy endosperm.Although these two tis-sues have the same developmental origin,they differ in morphology,cell fate,and storage product accu-mulation,with the mechanism largely unknown.Here,we report the identification and characterization of rice thick aleurone 1(ta1)mutant that shows an increased number of aleurone cell layers and increased contents of nutritional factors including proteins,lipids,vitamins,dietary fibers,and micronutrients.We identified that the TA1 gene,which is expressed in embryo,aleurone,and subaleurone in caryopses,en-codes a mitochondrion-targeted protein with single-stranded DNA-binding activity named OsmtSSB1.Cytological analyses revealed that the increased aleurone cell layers in ta1 originate from a developmental switch of subaleurone toward aleurone instead of starchy endosperm in the wild type.We found that TA1/OsmtSSB1 interacts with mitochondrial DNA recombinase RECA3 and DNA helicase TWINKLE,and down-regulation of RECA3 or TWINKLE also leads to ta1-like phenotypes.We further showed that mutation in TA1/OsmtSSB1 causes elevated illegitimate recombinations in the mitochondrial genome,altered mito-chondrial morphology,and compromised energy supply,suggesting that the OsmtSSB1-mediated mito-chondrial function plays a critical role in subaleurone cell-fate determination in rice.