A peptide chain release factor 2a gene regulates maize kernel development by modulating mitochondrial function  

作　　者：Hui Zhang Yijian Feng Kunyang Song Guofang Li Jiao Jin Jingjing Gao Yongtian Qin Hongqiu Wang Jinpeng Cheng Zonghua Liu Jihua Tang Zhiyuan Fu 

机构地区：[1]Key Laboratory of Wheat and Maize Crops Science/Collaborative Innovation Center of Henan Grain Crops/College of Agronomy,Henan Agricultural University,Zhengzhou 450046,Henan,China [2]The Shennong Laboratory,Zhengzhou 450002,Henan,China [3]Hebi Academy of Agricultural Sciences,Hebi 458030,Henan,China [4]Yunnan Tang Jihua Expert Workstation/Zhaotong Academy of Agricultural Sciences,Zhaotong 657000,Yunnan,China

出　　处：《The Crop Journal》2023年第6期1731-1741,共11页作物学报（英文版）

基　　金：the National Natural Science Foundation of China(31971893,U2004144);the Key Technologies R&D Program of Henan Province(232102111080,212102110043);Academician Expert Workstation(202305AF150082).

摘　　要：Mitochondrial protein translation that is essential for aerobic energy production includes four essential steps of the mitochondrial ribosome cycle,namely,initiation,elongation,termination of the polypeptide,and ribosome recycling.Translation termination initiates when a stop codon enters the A site of the mitochondrial ribosome where it is recognized by a dedicated peptide release factor(RF).However,RFs and mechanisms involved in translation in plant mitochondria,especially in monocotyledons,remain largely unknown.Here,we identified a crumpled kernel(crk5 allele)mutant,with significantly decreased kernel size,100-kernel weight,and an embryo-lethal phenotype.The Crk5 allele was isolated using map-based cloning and found to encode a mitochondrial localization RF2a.As it is an ortholog of Arabidopsis mitochondrial RF2a,we named the gene ZmmtRF2a.ZmmtRF2a is missing the 5th–7th exons in the crk5 resulting in deletion of domains containing motifs GGQ and SPF that are essential for release activity of RF,mitochondrial ribosome binding,and stop codon recognition.Western blot and qRT-PCR analyses indicate that the crk5 mutation results in abnormal mitochondrion structure and function.Intriguingly,we observed a feedback loop in the crk5 with up-regulated transcript levels detected for several mitochondrial ribosome and mitochondrial-related components,in particular mitochondrial complexes CI,CIV,and a ribosome assembly related PPR.Together,our data support a crucial role for ZmmtRF2a in regulation of mitochondrial structure and function in maize.

关 键 词：Embryo lethality MITOCHONDRION Peptide release factor 2 Zea mays 

分 类 号：S513[农业科学—作物学]