Dynamic polysome association TAS3 during symbiosis

ZANETTI MARÍA EUGENIA; TRAUBENIK SOLEDAD; REYNOSO MAURICIO ALBERTO; BLANCO FLAVIO ANTONIO; HOBECKER, KAREN VANESA

Bernal

Encuentro; II Reunión Argentina de Biología de ARNs no codificantes; 2018

Universidad Nacional de Quilmes

The trans-acting RNA3 (TAS3) is an evolutionarily conserved long non-coding RNA that results inthe production of trans-acting small interference RNA (tasiRNA) when targeted at two sites by themicroRNA390. In a previous work, we combined Translating Ribosome Affinity Purification (TRAP)with RNA-seq to characterize dynamic changes in the population of mRNAs associated to thetranslational machinery at early stages of the symbiotic interaction between Medicago truncatulaand Sinorhizobium meliloti. We found two alternative variants of TAS3 that are differentiallyrecruited to polysomes and modulate tasiRNAs production in response to S. meliloti. The longtranscript variant (TAS3) contains the two microRNA390 target sites and the short transcript variant(ALT TAS3) excludes the microRNA390 cleavable site, thus does not lead to tasiARFs production.Promoter reporter fusions demonstrated that TAS3 gene is active in epidemis, endodermis andpericycle of the differential zone of main and lateral roots, as well as in the meristematic zone oflateral roots. Under symbiotic conditions, activity of TAS3 promoter was detected at late stages ofthe interaction in cells reached by infection treads and in non-infected cells of the nodule. Inaddition, overexpression of TAS3 promoted elongation of emerged lateral roots, but did notsignificantly affect the symbiotic outcome. Ongoing experiments that evaluate the effect of ALTTAS3 overexpression will allow us to dissect the biological function of this alternative variant duringthe symbiotic interaction.