Characterisation of a spliced tomato microRNA

• Main Author: Tudor, Hannah Rachael
• Published: University of East Anglia 2011
• Subjects: 635.642
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.578250

MicroRNAs are short single stranded RNA molecules derived from longer precursors with a hairpin like structure. MiRNAs are taken up into a complex, which can then target mRNA for degradation. Mi.RNAs have been shown to play a role in plant development and stress responses. A novel tomato miRNA has been discovered in our group before I started my project. The secondary structure of the miRNA is unusual as it contains a 600nt intron which is spliced out. We discovered that the miRNA is differentially expressed within the leaves exhibiting a wave like pattern from the base of the leaf to the tip. There are similarities of the expression of this miRNA to sink-to-source transition suggesting that this miRNA may have a role in development from young leaves to mature leaves. The expression of this miRNA is highly increased when the tomato plant is grown in light conditions, and the longer un-spliced version of this miRNA is accumulated at a higher level in plants grown in dark conditions. Therefore we concluded that light controls the splicing of this miRNA. Furthermore looking at the wave-like expression of the miRNA within the leaves and the changes in expression with plants grown in light and dark conditions, it seems plausible that the miRNA is involved in the sink-to-source transition of leaves. Following this hypothesis several constructs of the miRNA have been produced which will be transformed into tomato to test this hypothesis. The discovery of this miRNA and the study of it so far have revealed many avenues of possible investigation. This miRNA seems to be integrally involved in plant growth and development. Further study would show how this miRNA functions in the plant, which may shed light on sink-to-source transition.