| Anthocyanins are flavonoids, which widely present in the cytosol of different tissues and organs of plant, and it’s safe, non-toxic. Tomato is rich in nutrients and it is usually treated as fruits or vegetables as well as a model plant. Improving tomato’s anthocyanin content has important practical significance. miRNAs are a class of endogenous small non-coding RNA with 21-24 nucleotides in length.. They can complementary pair with target mRNA induced its degradation or translational repression at post-transcriptional level. We produce a new thingking for the research anthocyanin biosynthesis through the discovery of miRNA and its post-transcriptional level regulation mechanism. miR858 is one of miRNA may be involved in plant anthocyanin biosynthesis regulation.Our study predicted and isolated clone miR858 sequence in tomato, through alignment of mature miR858 sequences among different species to verify its highly conservatism. The expression levels of miR858 higher in tomato leaf and bud than in the other tissues show its tissue-specific expression.To further elucidate the function of miR858, the qRT-PCR of T1 STTM858 transgenic plants show while the expression levels of miR858 reduces, the expression levels of target gene Sly-mybl2 and Sly-myb-like increase, and the expression levels of anthocyanin biosynthesis enzyme genes increase too. On the other hand, anthocyanin content increase. Sequence analysis for miR858 promoters in tomato and Arabidopsis thaliana find MBS(MYB binding site involved in drought-inducibility) in both of them, so we treat seeding in drought stress, and qRT-PCR results indicate miR858 expression induced by drought stress.These results indicate that, miR858 may negatively regulate anthocyanin biosynthesis by interacting with the target gene at post-transcriptional level, and response to drought stress. It provids the basis for depth research the miR858 function in anthocyanin biosynthesis and stress responses. |
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