Characterization of a novel allele encoding pheophorbide a oxygenase in rice. (4th March 2021)

• Record Type: Journal Article
• Authors: Zhang, Zhihong; He, Yan; Li, Liangjian; Zhang, Xiaobo; Xu, Xia; Shi, Yongfeng; Wu, Jian-Li
• Is Part Of: Plant signaling & behavior. Volume 16:Number 3(2021)
• Publication Date: 2021-03-04
• Subjects: Rice -- cell death -- pheophorbide a oxygenase -- chlorophyll -- chlorophyllase; Plant ecophysiology -- Periodicals; Plant cellular signal transduction -- Periodicals; Plant cellular signal transduction; Plant ecophysiology; Periodicals; Electronic journals; 581
• DOI: 10.1080/15592324.2020.1864606
• Languages: English
• ISSNs: 1559-2316

Abstract

ABSTRACT: We identified a rapid cell death 2 ( rcd2 ) mutant from an indica cultivar Zhongjian100 mutant bank. The red-brown lesions appeared firstly on young seedling leaves, then gradually merged and the leaves completely withered at the late tillering stage. rcd2 displayed apparent cell death at/around the lesions, accumulation of superoxide anion (O2 − ) and disturbed ROS scavenging system, impaired photosynthetic capacity with significantly reduced chlorophyll content. The lesion formation was controlled by a single recessive nuclear gene and induced by natural light as well as mechanical wounding. A single base mutation (A1726T) at the 6th exon of OsMH_03G0040800 resulted in I576F substitution in the encoding protein, pheophorbide a oxygenase (PAO). Functional complementation could rescue the mutant phenotype and PAO- knockout lines exhibited the similar phenotype to rcd2 . The activity of PAO decreased significantly while the content of PAO substrate, pheophorbide a, increased apparently in rcd2 . The expression of chlorophyll synthesis/degradation-related genes and the contents of metabolic intermediates were largely changed. Furthermore, the level of chlorophyllide a, the product of chlorophyllase, increased significantly, indicating chlorophyllase might play a role in chlorophyll degradation in rice. Our results suggested that the I576F substitution disrupted PAO function, leading to O2 − accumulation and chlorophyll degradation breakdown in rice.