|dc.description.abstract||The greenhouse effect has led to extreme climate around the world, such as extreme temperatures, heavy rain, drought and so on. These severe environmental conditions have seriously affected the survival and yield of crops. Understanding how crops like rice are resistant to environmental stresses is one of the important directions for improving survival and yields under different types of stresses. In general, rapid gene regulation affecting the subsequent protein production is one of important strategy to adapt and against environmental stresses in plants. Moreover, gene regulation can be preliminarily classified into transcriptional level and post-transcriptional level. In transcriptional level, for example, many studies have determined mechanisms how transcription factors affect stress tolerances. However, in contrast to transcriptional level, mechanisms of plants in post-transcriptional level is not well known. Thus, our subject of this article focuses on the mechanism of deadenylation, an initial step of mRNA turnover, in rice.
Studies in yeasts and mammals have indicated the deadenylation is mainly mediated by subunits of CCR4-NOT1 complex, CCR4 and CAF1. Also, it’s thought these deadenylation enzymes affects mRNA stability via poly(A) tail shortening, leading mRNA turnover or reducing translation efficiency. Although in plants, it has been proven that CCR4 and CAF1 affect the stress tolerance, related mechanisms aren’t clear. In this article, we provide some interesting findings as follows. First, not like its partner CCR4, the expansion of CAF1 homologs are distinct in rice. Among these rice CAF1 members, the divergence of protein sequences is obvious. Second, plant CCR4 members lacking LRR domain contain Mynd domain to interact with CAF1 in evolution. Third, only CAF1B-GFP located in P-bodies under normal condition, but CAF1H-GFP also aggregated as granule structures under heat stress. Fourth, expression patterns of each CAF1 member are divergent under different types of treatment. For example, only CAF1H expression is induced as well as small Hsps under heat stress. Fifth, CAF1H affected heat tolerance and seedling growth under heat stress in our experimental condition. These findings promote us a model which supposes CAF1H is recruited to P-bodies by other heat-induced mRNA binding proteins under heat stress. However, it should be further examined whether the function of CAF1H is involved in deadenylation and which genes are targets.||en_US|