Involvement of CAT in the detoxification of HT-induced ROS burst in rice anther and its relation to pollen fertility
HT-induced ROS burst in developing anther is closely related to the lowered CAT activity as the result of the markedly suppressed OsCATB transcript, thereby causing severe fertility injury for rice plants exposed to HT at meiosis stage.
The reproductive stage of rice plants is highly sensitive to heat stress. In this paper, different rice cultivars were used to investigate the relationship of HT-induced floret sterility with reactive oxygen species (ROS) detoxification in rice anthers under well-controlled climatic conditions. Results showed that high temperature (HT) exposure significantly enhanced the ROS level and malondialdehyde (MDA) content in developing anther, and the increase in ROS amount in rice anther under HT exposure was closely associated with HT-induced decline in the activities of several antioxidant enzymes. For various antioxidant enzymes, SOD and CAT were more susceptible to the ROS burst in rice anther induced by HT exposure than APX and POD, in which SOD and CAT activity in developing anther decreased significantly by HT exposure, whereas APX activity was relatively stable among different temperature regimes. HT-induced decrease in CAT activity was attributable to the suppressed transcript of OsCATB. This occurrence was strongly responsible for HT-induced increase in ROS level and oxidative-damage in rice anther, thereby it finally caused significant reduction in pollen viability and floret fertility for the rice plants exposed to HT during meiosis. Exogenous application of 1000 µM salicylic acid (SA) may alleviate HT-induced reduction in pollen viability and floret fertility, concomitantly with the increased CAT activity and reduced ROS level in rice anther.
KeywordsHigh temperature Reactive oxygen species (ROS) Antioxidant enzymes CAT isoforms Floret fertility Rice (Oryza sativa L.)
Cytoplasmic male sterility
Programmed cell death
Reactive oxygen species
The authors are indebted to National Key Research and Development Plan of China (No. 2016YFD0300502), National Natural Science Foundation of China (No. 31571602) and Zhejiang Provincial Natural Science Foundation of China (LZ15C130001) for its financial support to this research project.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
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