ABA Affects Brassinosteroid-Induced Antioxidant Defense via ZmMAP65-1a in Maize Plants.
Brassinosteroids (BRs) and ABA co-ordinately regulate water deficit tolerance in maize leaves. ZmMAP65-1a, a maize microtubule-associated protein (MAP) which plays an essential role in BR-induced antioxidant defense, has been characterized previously. However, the interactions among BR, ABA and ZmMAP65-1a in water deficit tolerance remain unexplored. In this study, we demonstrated that ABA was required for BR-induced antioxidant defense via ZmMAP65-1a by using biochemical blocking and ABA biosynthetic mutants. The expression of ZmMAP65-1a in maize leaves and mesophyll protoplasts could be increased under polyethylene glycol- (PEG) stimulated water deficit and ABA treatments. Furthermore, the importance of ABA in the early pathway of BR-induced water deficit tolerance was demonstrated by limiting ABA availability. Blocking ABA biosynthesis biochemically or by a null mutation inhibited the downstream gene expression of ZmMAP65-1a and the activity of ZmMAPK5 in the pathway. It also affected the activities of BR-induced antioxidant defense-related enzymes, namely ascorbate peroxidase (APX), catalase (CAT), glutathione reductase (GR), superoxide dismutase (SOD) and NADPH oxidase. In addition, combining results from transiently overexpressed or silenced ZmMAP65-1a in mesophyll protoplasts, we discovered that ZmMAP65-1a mediated the ABA-induced gene expression and activities of APX and SOD. Surprisingly, silencing of ZmMAP65-1a in mesophyll protoplasts did not alter the gene expression of ZmCCaMK and vice versa in response to ABA. Taken together, our data indicate that water deficit-induced ABA is a key mediator in BR-induced antioxidant defense via ZmMAP65-1a in maize.
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Yuan
Y
Zhu
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Weijuan
W
Liu
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Yu
Y
Sheng
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Juan
J
Zhang
Joint BioEnergy Institute and Physical Biosciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
Tsanyu
T
Chiu
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Jingwei
J
Yan
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China National Key Laboratory of Crop Genetics and Germplasm Enhancement, Nanjing Agricultural University, Nanjing 210095, China.
Mingyi
M
Jiang
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Mingpu
M
Tan
College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China ayzhang@njau.edu.
Aying
A
Zhang
D000040:Abscisic Acid / Q000378:metabolism* / Q000494:pharmacology; D000975:Antioxidants / Q000378:metabolism*; D060387:Ascorbate Peroxidases / Q000235:genetics / Q000378:metabolism; D053898:Biosynthetic Pathways / Q000235:genetics; D060406:Brassinosteroids / Q000378:metabolism* / Q000494:pharmacology; D017871:Calcium-Calmodulin-Dependent Protein Kinases / Q000235:genetics / Q000378:metabolism; D002374:Catalase / Q000235:genetics / Q000378:metabolism; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D005980:Glutathione Reductase / Q000235:genetics / Q000378:metabolism; D008869:Microtubule-Associated Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism; D009154:Mutation; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D010802:Phylogeny; D018515:Plant Leaves / Q000166:cytology / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000145:classification / Q000235:genetics / Q000378:metabolism*; D011523:Protoplasts / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013482:Superoxide Dismutase / Q000235:genetics / Q000378:metabolism; D014867:Water / Q000378:metabolism; D003313:Zea mays / Q000235:genetics / Q000378:metabolism*
D000975:Antioxidants; D060406:Brassinosteroids; D008869:Microtubule-Associated Proteins; D010940:Plant Proteins; D014867:Water; D000040:Abscisic Acid; D060387:Ascorbate Peroxidases; D002374:Catalase; D013482:Superoxide Dismutase; D019255:NADPH Oxidases; D005980:Glutathione Reductase; D017871:Calcium-Calmodulin-Dependent Protein Kinases; D020928:Mitogen-Activated Protein Kinases
ABA; Antioxidant defense; Brassinosteroid; Water deficit; ZmMAP65‐1a; ZmMAPK5