title: Reactive oxygen species regulate leaf pulvinus abscission zone cell separation in response to water-deficit stress in cassava.
abstract: Cassava (Manihot esculenta Crantz) plant resists water-deficit stress by shedding leaves leading to adaptive water-deficit condition. Transcriptomic, physiological, cellular, molecular, metabolic, and transgenic methods were used to study the mechanism of cassava abscission zone (AZ) cell separation under water-deficit stress. Microscopic observation indicated that AZ cell separation initiated at the later stages during water-deficit stress. Transcriptome profiling of AZ suggested that differential expression genes of AZ under stress mainly participate in reactive oxygen species (ROS) pathway. The key genes involved in hydrogen peroxide biosynthesis and metabolism showed significantly higher expression levels in AZ than non-separating tissues adjacent to the AZ under stress. Significantly higher levels of hydrogen peroxide correlated with hydrogen peroxide biosynthesis related genes and AZ cell separation was detected by microscopic observation, colorimetric detection and GC-MS analyses under stress. Co-overexpression of the ROS-scavenging proteins SOD and CAT1 in cassava decreased the levels of hydrogen peroxide in AZ under water-deficit stress. The cell separation of the pulvinus AZ also delayed in co-overexpression of the ROS-scavenging proteins SOD and CAT1 plants both in vitro and at the plant level. Together, the results indicated that ROS play an important regulatory role in the process of cassava leaf abscission under water-deficit stress.
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
authors.forename: Wenbin
authors.initials: W
authors.lastname: Liao
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
authors.forename: Gan
authors.initials: G
authors.lastname: Wang
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
authors.forename: Yayun
authors.initials: Y
authors.lastname: Li
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
authors.forename: Bin
authors.initials: B
authors.lastname: Wang
authors.affiliation: National Key Laboratory of Plant Molecular Genetics, CAS Center for Excellence in Molecular Plant Sciences, Institute of Plant Physiology and Ecology, Shanghai Institutes for Biological Sciences, Chinese Academy of Science, Shanghai 200032, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Zhang
authors.affiliation: Institute of Tropical Bioscience and Biotechnology, Chinese Academy of Tropical Agricultural Sciences, Haikou 571101, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Peng
mesh_terms: D003681:Dehydration / Q000235:genetics*; D020869:Gene Expression Profiling; D018506:Gene Expression Regulation, Plant; D006861:Hydrogen Peroxide / Q000378:metabolism; D002365:Manihot / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D018516:Pulvinus / Q000166:cytology / Q000235:genetics / Q000254:growth & development; D017382:Reactive Oxygen Species / Q000378:metabolism*; D059467:Transcriptome / Q000235:genetics*; D014867:Water / Q000378:metabolism
chemical_list: D017382:Reactive Oxygen Species; D014867:Water; D006861:Hydrogen Peroxide