Long npcRNAs in the control of root developmental plasticity in Arabidopsis

ARIEL, FD; MERCHAN, F; THIEBAUT, F; MARIN, E; NUSSAUME, L; FERREIRA, P; CRESPI, M

Sant Feliu

Simposio; Epigenetics in Context: from ecology to evolution; 2011

ESF-EMBO

Non protein coding RNAs (npcRNAs) are emerging as key players in the regulation of varied important cellular processes. Long npcRNA represent a class of riboregulators, which either act directly in this long form or are processed into shorter small si/miRNAs. Certain class of endogenous siRNAs derived from pairs of natural antisense transcripts (NATs) whereas other antisense RNAs may have specific localisations at tissular, cellular and sub-cellular levels and participate in epigenetic regulatory mechanisms. In our Lab, a bioinformatic approach identified 76 Arabidopsis thaliana npcRNAs including several siRNA precursors and antisense RNAs. Abiotic stress, such as phosphate starvation, drought or salt stress altered the accumulation of many of these npcRNAs. The behaviour of a set of long npcRNAs in response to auxins, ABA and stress indicates that they may mediate the environmental control of lateral root formation. Besides, we have shown that certain siRNAs accumulate under the same conditions, suggesting an epigenetic link. Another stress-induced long antisense RNA interacts with the overlapping transcript to generate a shorter RNA molecule. This RNA led, likely through RDR2, to the generation of a long double-stranded RNA that is nto processed. The nucleotide sequence of this locus is conserved in brassicaceae and overexpression of this locus led to a developmental phenotype. This regulation may reveal a novel conserved mechanism mediated by an antisense RNA to control gene expression. We think that environmental control of long and small npcRNAs may mediate epigenetic mechanisms controlling root developmental plasticity.