In future climates, rice could more frequently be subjected to simultaneous high temperature(HT) and water stress(WS) during sensitive developmental stages such as flowering. In this study, two rice genotypes were exposed to HT, WS and combined high temperature and water stress(WS + HT) during flowering to quantify their response through anther dehiscence. Gene expression profiles of 15 selected Os DIRs revealed differences among stresses and between varieties. The targeted gene Os DIR-08, which was considered to be a HT stress candidate gene, was decreasingly expressed from the 1st d to the 4th d under HT stress in Nagina 22(N22) while increased in Moroberekan. Varies of the expression of Os DIR genes in stresses intuitively reflects on the lignin-staining at the anther dehisced sites, which implied a negative relationship between the lignin biosynthesis and Os DIRs' expression. Anther dehiscence disturbed by HT and WS + HT stress showed a negative cumulative effect in HT sensitive variety Moroberekan but not in N22. Higher level of anther dehiscence in N22 under HT and WS + HT stress indicated its true tolerance of HT and to WS + HT during anthesis. The differentially expressed of Os DIR(s) under various managed stresses caused the difference of the lignin-staining at the anther dehisced site in N22, and thus transformed anther dehiscence correspondingly might be one of the main reasons for the tolerance.
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