A calcium-binding protein, rice annexin OsANN1, enhances heat stress tolerance by modulating the production of H₂O₂

Abstract

OsANN1 is a member of the annexin protein family in rice. The function of this protein and the mechanisms of its involvement in stress responses and stress tolerance are largely unknown. Here it is reported that OsANN1 confers abiotic stress tolerance by modulating antioxidant accumulation under abiotic stress. OsANN1-knockdown [RNA interference (RNAi)] plants were more sensitive to heat and drought stresses, whereas OsANN1-overexpression (OE) lines showed improved growth with higher expression of OsANN1 under abiotic stress. Overexpression of OsANN1 promoted SOD (superoxide dismutase) and CAT (catalase) activities, which regulate H2O2 content and redox homeostasis, suggesting the existence of a feedback mechanism between OsANN1 and H2O2 production under abiotic stress. Higher expression of OsANN1 can provide overall cellular protection against abiotic stress-induced damage, and a significant accumulation of OsANN1-green fluorescent protein (GFP) signals was found in the cytosol after heat shock treatment. OsANN1 also has calcium-binding and ATPase activities in vitro, indicating that OsANN1 has multiple functions in rice growth. Furthermore, yeast two-hybrid and bimolecular fluorescence complementation (BiFC) assays demonstrated that OsANN1 interacts with OsCDPK24. This cross-talk may provide additional layers of regulation in the abiotic stress response.

Ectopic overexpression of abiotic stress-induced rice annexin,OsAnn5potentiates tolerance to abiotic stresses

“…The OsAnn5 calcium binding activity assay performed in two methods. In the first method, three different concentrations of the CaCl2 i.e 10 mM, 20 mM, 30 mM CaCl2 was added to the OsANN5 overexpressed BL21 cell lysate samples to precipitate the calcium bound proteins (Qiao et al, 2015). Then each sample was subjected to centrifugation (12,000 rpm for 15 min) and the supernatant, precipitate were separated.…”

“…Out of the ten rice annexins identified in the rice genome (Jami et al, 2012), OsANN1 has been characterized recently for its functional role in calcium-mediated heat stress tolerance in rice (Qiao et al, 2015). Knock out of another annexin, OsAnn3 in rice plants lead to susceptibility under cold stress (Shen et al, 2017).…”

A Cotton Annexin Affects Fiber Elongation and Secondary Cell Wall Biosynthesis Associated with Ca2+ Influx, ROS Homeostasis, and Actin Filament Reorganization

“…Arabidopsis AnnAt1 was subsequently postulated to link ROS-and cytosolic Ca 2+ concentration-driven signaling and could be involved in hydrogen peroxide (H 2 O 2 )-activated Ca 2+ fluxes (Laohavisit et al, 2012;Richards et al, 2014). Recently, the rice (Oryza sativa) annexin OsANN1 was shown to interact with OsCDPK24 and enhance heat stress tolerance by modulating the production of H 2 O 2 (Qiao et al, 2015). Actin binding is limited to a small number of animal annexins, and, as a generalization, actin-annexin interaction appears to be restricted to regions close to animal membranes (Hayes et al, 2004).…”

Molecular characterisation and function analysis of the rice OsDUF872 family

“…The major ROS-scavenging enzymes in organisms include superoxide dismutase (SOD), ascorbate peroxidase (APX) and catalase (CAT). At present, while some genes have been used to enhance heat tolerance in rice and have achieved certain effects [16][17][18][19], the number of such genes still remains rather small.…”