The lncRNA POSEIDON is required for bacterial infection and the development of nitrogen-fixing nodules

MILAGROS FERRARI; FLAVIO ANTONIO BLANCO; SOLEDAD TRAUBENIK; MARÍA EUGENIA ZANETTI

Congreso; Plant Biology 2020 Worldwide; 2020

American Society of Plant Biologists (ASPB)

Legumes plants can establish a nitrogen-fixing symbiosis with bacteria from the genus Rhizobium. This interaction involves the formation of a new lateral root organ, the nodule, and the suppression of the immune response that will allow rhizobia to infect the root tissue. The activation and coordination of these two genetic programs require the reprogramming of root cells for symbiosis, which is accompanied by dramatic alterations in gene expression. The association of RNAs with the translational machinery is a regulatory mechanism that contributes to this reprogramming of roots cells for symbiosis. We have shown that long non-coding RNAs (lncRNAs) are regulated at the level of association to the translational machinery during the root nodule symbiosis between Medicago truncatula and Sinhorihizobium meliloti. This high throughput analysis led us to identify POSEIDON (Polysome associated symbiotically engaged intergenic down regulated long non-coding RNA) as a lncRNA that decreases its association to the translational machinery in response to rhizobia. We identified two isoforms generated from POSEIDON locus, a long isoform of 1115, and a short isoform of 450 nucleotides. Knockdown of each of these isoforms affected the frequency and progression of infection events and caused significant changes in the number, development, and distribution of root nodules. Our results indicate that POSEIDON mediates the infection process as well as the development of functional nodules. This lncRNA, which is associated with the translational machinery, might act repressing or activating the translation of its transcript targets. Elucidating the mechanisms by which POSEIDON exerts its activity will allow a better understanding of the biological phenomenon that leads to the biological nitrogen-fixation and transfer this information to programs for the improvement of relevant agronomic traits.