Rice OsiSAP7 negatively regulates ABA stress signalling and imparts sensitivity to water-deficit stress in Arabidopsis. (August 2015)

• Record Type: Journal Article
• Authors: Sharma, Gunjan; Giri, Jitender; Tyagi, Akhilesh K.
• Is Part Of: Plant science. Volume 237(2015:Aug.)
• Page Start: 80
• Page End: 92
• Publication Date: 2015-08
• Subjects: COP1 constitutive photomorphogenic 1 -- DCFDA 2′, 7′-dichlorofluorescein diacetate -- DREB dehydration-responsive element binding protein -- DRIP1/2 DREB-interacting protein1/2 -- HOS1 high expression of osmotically responsive 1 -- ICE1 inducer of CBF expression 1 -- NBs nuclear bodies -- OsDIS1 drought-induced SINA protein 1 -- OST1 open stomata 1 -- RLCK253 receptor like cytoplasmic kinase 253 -- ROS reactive oxygen species -- TNF tumour necrosis factor; A20/AN1 -- Abscisic acid -- OsiSAP7 -- Stress associated protein (SAP) -- Sub-nuclear body -- Zinc-finger; Botany -- Periodicals; Botanique -- Périodiques; 580
• DOI: 10.1016/j.plantsci.2015.05.011
• Languages: English
• ISSNs: 0168-9452

Abstract

Highlights: OsiSAP7 expression was down-regulated under ABA and water-deficit stress in rice. OsiSAP7 localized in nucleus or sub-nuclear speckles. OsiSAP7 exhibits an in vitro E3 ubiquitin ligase activity. OsSAP7 imparts ABA insensitivity and sensitivity to water-deficit in Arabidopsis. OsiSAP7 negatively affects stress signalling. Abstract: Stress associated protein ( SAP ) genes in plants regulate abiotic stress responses. SAP gene family consists of 18 members in rice. Although their abiotic stress responsiveness is well established, the mechanism of their action is poorly understood. OsiSAP7 was chosen to investigate the mechanism of its action based on the dual nature of its sub-cellular localization preferentially in the nucleus or sub-nuclear speckles upon transient expression in onion epidermal cells. Its expression was down-regulated in rice seedlings under abiotic stresses. OsiSAP7 was localized evenly in the nucleus under unstressed conditions and in sub-nuclear speckles on MG132 treatment. OsiSAP7 exhibits E3 ubiquitin ligase activity in vitro . Abiotic stress responses of OsiSAP7 were assessed by its overexpression in Arabidopsis under the control of a stress inducible promoter rd29A . Stress response assessment was done at seed germination and advanced stages of development. Transgenics were ABA insensitive at seed germination stage and sensitive to water-deficit stress at advanced stage as compared to wild type (WT). They were also impaired in ABA and stress-responsive gene expression. Our study suggests that OsiSAP7 acts as a negative regulator of ABA and water-deficit stress signalling by acting as an E3 ubiquitin ligase.