title: The cysteine protease CEP1, a key executor involved in tapetal programmed cell death, regulates pollen development in Arabidopsis.
abstract: Tapetal programmed cell death (PCD) is a prerequisite for pollen grain development in angiosperms, and cysteine proteases are the most ubiquitous hydrolases involved in plant PCD. We identified a papain-like cysteine protease, CEP1, which is involved in tapetal PCD and pollen development in Arabidopsis thaliana. CEP1 is expressed specifically in the tapetum from stages 5 to 11 of anther development. The CEP1 protein first appears as a proenzyme in precursor protease vesicles and is then transported to the vacuole and transformed into the mature enzyme before rupture of the vacuole. cep1 mutants exhibited aborted tapetal PCD and decreased pollen fertility with abnormal pollen exine. A transcriptomic analysis revealed that 872 genes showed significantly altered expression in the cep1 mutants, and most of them are important for tapetal cell wall organization, tapetal secretory structure formation, and pollen development. CEP1 overexpression caused premature tapetal PCD and pollen infertility. ELISA and quantitative RT-PCR analyses confirmed that the CEP1 expression level showed a strong relationship to the degree of tapetal PCD and pollen fertility. Our results reveal that CEP1 is a crucial executor during tapetal PCD and that proper CEP1 expression is necessary for timely degeneration of tapetal cells and functional pollen formation.
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China.
authors.forename: Dandan
authors.initials: D
authors.lastname: Zhang
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China.
authors.forename: Di
authors.initials: D
authors.lastname: Liu
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China.
authors.forename: Xiaomeng
authors.initials: X
authors.lastname: Lv
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Wang
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China.
authors.forename: Zhili
authors.initials: Z
authors.lastname: Xun
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China.
authors.forename: Zhixiong
authors.initials: Z
authors.lastname: Liu
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China.
authors.forename: Fenglan
authors.initials: F
authors.lastname: Li
authors.affiliation: College of Biological Sciences and Biotechnology, Beijing Forestry University, Beijing 100083, People's Republic of China luhai1974@bjfu.edu.cn.
authors.forename: Hai
authors.identifier: http://orcid.org/0000-0003-0937-954X
authors.initials: H
authors.lastname: Lu
mesh_terms: D017209:Apoptosis; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation; D057056:Cysteine Proteases / Q000235:genetics / Q000378:metabolism; D035264:Flowers / Q000201:enzymology / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure; D018506:Gene Expression Regulation, Plant; D008957:Models, Genetic; D009154:Mutation; D051479:Plant Infertility; D011058:Pollen / Q000201:enzymology / Q000235:genetics / Q000502:physiology / Q000648:ultrastructure; D021381:Protein Transport; D013997:Time Factors; D014617:Vacuoles / Q000648:ultrastructure
chemical_list: D029681:Arabidopsis Proteins; C000592797:At1g47485 protein, Arabidopsis; D057056:Cysteine Proteases