Study of the role of pathways regulated by microRNA156 in the control of early ovary development in tomato (Solanum lycopersicum L.) by transcriptional and post-translational mechanisms

Abstract

The fleshy fruit development is an important agronomic factor. Understanding the factors that control this process is the basis for the development of various biotechnological tools applicable to the production of diverse plant cultures. Small non-coding RNAs regulate members of a huge array of gene families involved in all stages of fruit development, from early carpel development to the late stages of fruit ripening, characterizing regulatory pathways where these RNAs play a central role. Some members of the SQUAMOSA promoter binding protein-like (SPL) transcription factor family are post-transcriptionally regulated by microRNA156 (miR156).. It was recently showed by our research group that several genes that regulate early ovary development are regulated by the miR156/SPL pathway. These genes affect carpel development and fruit determination. The AtMIR156b overexpression in tomato plants led to the inhibition of some SPL genes and misregulated genes related to boundary establishment (such as GOBLET, GOB) and meristem maintenance (such as Tomato Knotted2, TKN2), resulting in abnormal flowers with extra carpels and indeterminate fruits. TKN2 and GOB homologs in Arabidopsis interact directly between them in the regulation of leaf development. Furthermore, it had been shown that Arabidopsis SPL9 transcription factor, homolog of tomato SlySBP15, controls a post-transcriptional network that regulates leaf complexity. This network also involves other tomato homolog genes (GOBLET and LANCEOLATE) which are related to early ovary development. The present work aims at elucidating the transcriptional and post-translational mechanisms by which miR156/SPL pathway regulates early ovary development.