Overexpression of Arabidopsis acyl-CoA-binding protein ACBP2 enhances drought tolerance.
Arabidopsis thaliana acyl-CoA-binding protein 2 (ACBP2) is a stress-responsive protein that is also important in embryogenesis. Here, we assign a role for ACBP2 in abscisic acid (ABA) signalling during seed germination, seedling development and the drought response. ACBP2 was induced by ABA and drought, and transgenic Arabidopsis overexpressing ACBP2 (ACBP2-OXs) showed increased sensitivity to ABA treatment during germination and seedling development. ACBP2-OXs also displayed improved drought tolerance and ABA-mediated reactive oxygen species (ROS) production in guard cells, thereby promoting stomatal closure, reducing water loss and enhancing drought tolerance. In contrast, acbp2 mutant plants showed decreased sensitivity to ABA in root development and were more sensitive to drought stress. RNA analyses revealed that ACBP2 overexpression up-regulated the expression of Respiratory Burst Oxidase Homolog D (AtrbohD) and AtrbohF, two NAD(P)H oxidases essential for ABA-mediated ROS production, whereas the expression of Hypersensitive to ABA1 (HAB1), an important negative regulator in ABA signalling, was down-regulated. In addition, transgenic plants expressing ACBP2pro:GUS showed beta-glucuronidase (GUS) staining in guard cells, confirming a role for ACBP2 at the stomata. These observations support a positive role for ACBP2 in promoting ABA signalling in germination, seedling development and the drought response.
School of Biological Sciences, The University of Hong Kong, Hong Kong, China.
Zhi-Yan
ZY
DU
Mo-Xian
MX
Chen
Qin-Fang
QF
Chen
Shi
S
Xiao
Mee-Len
ML
Chye
D000040:Abscisic Acid / Q000494:pharmacology; D000222:Adaptation, Physiological / Q000187:drug effects; D017360:Arabidopsis / Q000187:drug effects / Q000235:genetics / Q000254:growth & development / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D055864:Droughts; D018506:Gene Expression Regulation, Plant / Q000187:drug effects; D018525:Germination / Q000187:drug effects / Q000235:genetics; D005966:Glucuronidase / Q000378:metabolism; D009154:Mutation / Q000235:genetics; D018515:Plant Leaves / Q000187:drug effects / Q000502:physiology; D018517:Plant Roots / Q000187:drug effects / Q000254:growth & development; D054046:Plant Stomata / Q000166:cytology / Q000187:drug effects / Q000502:physiology; D030821:Plants, Genetically Modified; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D036226:Seedlings / Q000187:drug effects / Q000235:genetics / Q000254:growth & development; D012639:Seeds / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics
C419263:ACBP2 protein, Arabidopsis; D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; D000040:Abscisic Acid; D005966:Glucuronidase