Abstract
Background: The health and physiology of flag leaves are closely related to rice yield, and flag leaves play an important role in providing photosynthetic products during grain filling, many breeding studies have tried to improve the performance of flag leaves. However, there are few studies on the heterosis of rice flag leaves up to now. Results: Thus, the present research is focused on the flag leaves heterosis of a widely used late-cropping indica super hybrid rice combination WFYT025 in China using a high-throughput next-generation RNA-seq strategy under different environment with two stages, trying to find some genes related to photosynthesis, transpiration, and development of seeds. Mid-parent heterosis (MPH) and higher parent heterosis (HPH) were estimated for the heterosis of flag leaf. Under the environment of middle rice, the number of genes up-regulated in CHT025, WFB and WFYT025 were 892,1,273 and 819, down-regulated in CHT025, WFB and WFYT025 were 616,1934 and 2196, respectively. Among the SDGhps on the first day after flowering, 10.9% had a dominant effect, 41.81% had a partial dominant effect, 22.07% had an additive effect and the remaining 25.22% had an over-dominant effect. Meanwhile, on the tenth day after flowering, there were 491 genes, accounting for 27.16%, showed over-dominance; 222 genes, accounting for 12.28%, showed dominance; 760 genes, accounting for 42.04%, showed partial dominance; and 335 genes, accounting for 18.52%, showed additive effect. Conclusion: The co-expressed gene sets via weighted gene co-expression network analysis (WGCNA) were identified, and total of 5,000 highly expressed genes were divided into 24 co-expression groups. In the two stages, we found 9 identical transcription factors. Except for 5 reported TFs, the other 4 TFs may play an important role in grain number and photosynthesis heterosis.
High Nitrogen Levels Alleviate Yield Loss of Super Hybrid Rice Caused by High Temperatures During the Flowering Stage
