Overexpression of a small heat‐shock‐protein gene enhances tolerance to abiotic stresses in rice

Rice (Oryza sativa L.) is one of the most important crops in the world which survives from various abiotic stresses in natural environments with specific stress-involved genes expressed. Plant sHSPs (small heat-shock proteins) were reported to respond to abiotic stresses. To improve the understanding of sHSPs in rice, we characterized heat-shock-protein gene OsHSP18.6 here. OsHSP18.6 could be induced by diverse stresses, such as drought, salt and cold, especially under heat. The gene was found expressed in root, stem, leaf, internode and spikelet. Overexpression of OsHSP18.6 results in increased thermotolerance and exhibits universal tolerance to stresses tested, including heat, drought, salt and cold. Lower levels of malondialdehyde (MDA) and greater activities of catalase (CAT) and superoxide dismutase (SOD) were observed in OsHSP18.6-overexpression rice under heat and drought. OsHSP18.6-overexpression lines indicated decreased sterile rates under hot weather without remarkable changes in most of other agronomic traits compared with wild-type plants.