Heat shock factor OsHsfB2b negatively regulates drought and salt tolerance in rice.
CONCLUSIONS
Expression of OsHsfB2b was strongly induced by heat, salt, ABA and PEG treatments. Drought and salt tolerances were significantly decreased by OsHsfB2b overexpression, but were enhanced by RNA interference.
Plants have more than 20 heat shock factors (Hsfs) that were designated class A, B, and C. Many members of Class A Hsfs were characterized as activators of transcription, but the functional roles of class B and C Hsfs have not been fully recognized. OsHsfB2b is a member of class B Hsfs in rice (Oryza sativa). Expression of OsHsfB2b was strongly induced by heat, salt, abscisic acid (ABA) and polyethylene glycol (PEG) treatments but was almost not affected by cold stress. Drought and salt tolerances were significantly decreased in OsHsfB2b-overexpressing transgenic rice, but were enhanced in the OsHsfB2b-RNAi transgenic rice. Under drought stress, the OsHsfB2b-overexpressing transgenic rice exhibited increased relative electrical conductivity (REC) and content of malondialdehyde (MDA) and decreased proline content compared with the wild type, while the lower REC and MDA content and increased proline content were found in the OsHsfB2b-RNAi transgenic rice. These results suggest that OsHsfB2b functions as a negative regulator in response to drought and salt stresses in rice, with its existing B3 repression domain (BRD) that might be necessary for the repressive activity. The present study revealed the potential value of OsHsfB2b in genetic improvement of rice.
Hunan Provincial Key Laboratory for Germplasm Innovation and Utilization of Crop, Hunan Agricultural University, Changsha, 410128, Hunan, China.
Jianhua
J
Xiang
Jing
J
Ran
Jie
J
Zou
Xiaoyun
X
Zhou
Ailing
A
Liu
Xianwen
X
Zhang
Yan
Y
Peng
Ning
N
Tang
Guangyu
G
Luo
Xinbo
X
Chen
D055864:Droughts; D018506:Gene Expression Regulation, Plant; D017343:Genes, Plant / Q000235:genetics; D006360:Heat-Shock Proteins / Q000378:metabolism*; D012275:Oryza / Q000235:genetics / Q000502:physiology*; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism*; D030821:Plants, Genetically Modified; D034622:RNA Interference; D060888:Real-Time Polymerase Chain Reaction; D055049:Salt Tolerance / Q000502:physiology*; D013312:Stress, Physiological / Q000235:genetics
D006360:Heat-Shock Proteins; D010940:Plant Proteins