The effect of high temperature stress on male and female reproduction in plants

Humanity confronts a major transition in the global environment. With the continued rise in atmospheric greenhouse gases, and wide-spread land transformation, the climate of the planet could warm to levels that have not existed for tens of millions of years. Crop yields are particularly vulnerable to high temperatures and plant reproduction is amongst the most sensitive of the physiological components at temperatures above 30 °C. In this review, we examine the effect of high temperatures on plant reproduction in general, and then focus on heat-induced failure of male and female reproduction in crop and model plant species in order to evaluate the patterns and mechanisms controlling heat sterility responses. The main objective is to provide breeders and molecular engineers with an understanding of the bottlenecks for successful reproductive development at high temperatures. Although numerous stages of male and female reproduction are impacted by elevated temperatures, the collective body of research supports the view that the uninucleate stage of male reproductive development is highly sensitive to levels of heat stress currently experienced by many crop species. Thus, high priority should be given to identification of mechanisms leading to high temperature sensitivity of this stage of development.