文章标题：A chlorophyll a oxygenase 1 gene ZmCAO1 contributes to grain yield and waterlogging tolerance in maize

作者列表：Li Qin, Zhou Shuangzhen, Liu Wenyu, Zhai Zhensheng, Pan Yitian, Liu Changchang, Chern Mawsheng, Wang Hongwei, Huang Min, Zhang Zuxin, Tang Jihua, Du Hewei

发表时间：2021-2-11

期刊：JOURNAL OF EXPERIMENTAL BOTANY

影响因子：6.992

DOI:10.1093/jxb/erab059

Abstract

Chlorophylls function in photosynthesis, and are critical to plant developmental processes and responses to environmental stimuli. Chlorophyll b is synthesized from chlorophyll a by chlorophyll a oxygenase (CAO). Here, we characterize a yellow-green leaf (ygl) mutant and identify the causal gene which encodes a chlorophyll a oxygenase in maize (ZmCAO1). A 51 bp Popin transposon insertion in ZmCAO1 strongly disrupts its tranｓcription. Low enzyme activity of ZmCAO1 leads to reduced concentrations of chlorophyll a and chlorophyll b, resulting in the yellow-green leaf phenotype of the ygl mutant. The net photosynthetic rate, stomatal conductance, and transpiration rate are decreased in the ygl mutant, while concentrations of δ-aminolevulinic acid (ALA), porphobilinogen (PBG) and protochlorophyllide (Pchlide) are increased. In addition, a ZmCAO1 mutation results in down-regulation of key photosynthetic genes, limits photosynthetic assimilation, and reduces plant height, ear size, kernel weight, and grain yield. Furthermore, the zmcao1 mutant shows enhanced reactive oxygen species production leading to sensitivity to waterlogging. These results demonstrate the pleiotropy of ZmCAO1 function in photosynthesis, grain yield, and waterlogging tolerance in maize.