Translational reprograming during root nodule symbiosis entails dynamic polysome association of coding and non-coding RNAs

MARIA EUGENIA ZANETTI

Quilmes

Conferencia; II Argentine Meeting on Non Coding RNA Biology; 2018

Universidad de Quilmes

mRNA translation mediates developmental and adaptive responses in plants, but the consequences of this level of regulation in the reprogramming of root cells for symbiosis have remained largely unexplored. A Translating Ribosome Affinity Purification (TRAP) approach combined with RNA-seq revealed that adjustments in the translatome were poorly correlated with changes in the transcriptome, and identified protein-coding and non-coding RNAs (ncRNAs) that change their association to the translational machinery in response to bacterial infection. Some of these ncRNAs exhibited cell-specific regulation during symbiosis. Differential association of two alternative transcript variants of the trans-acting RNA 3 (TAS3) to the translational machinery contributes to reduce tasiRNA biogenesis at early stages of the symbiotic process, which proved to be required for the establishment of a successful interaction between legumes and rhizobia. In addition, a significant proportion of transnationally regulated transcripts are enriched in chromatin remodeling, transcriptional regulation and mRNA stability functional categories. One of them encodes SUPERKILLER 3 (SKI3), a component of the SKI complex involved in the 3´to 5´cytoplasmic mRNA degradation via the exosome pathway. Silencing of SKI3 altered formation and development of symbiotic organs, but not bacterial infection. Our results provide new insights into the translational reprogramming of gene expression during symbiosis and highlight the importance of the translatomic approach to identify protein coding and non-coding RNAs with unprecedented functions in nodule development.