DNA methylation and histone modification: Roles in the reprogramming of the gene expression during symbiosis

FERRARI, MILAGROS; TRAUBENIK SOLEDAD; ZANETTI MARIA EUGENIA

Santa Fé

Congreso; XXIII Argentinian meeting of Plant Physiology; 2021

Sociedad Argentina de Fisiología Vegetal

Legume plants have the capacity to associate with soil bacteria collectively known as rhizobia when the nitrogen availability in the soil is low. Rhizobia incorporate atmospheric nitrogen into reduced forms assimilable by plants in a process known as a biological nitrogen-fixation (BNF). In this process the plant forms a new organ, the nodule, where the bacteria reside and BNF takes place. The formation of nitrogen fixing is accompanied by dramatic changes in gene expression in the root cells engaged in symbiosis. We have previously showed that translational changes of pre-existing mRNAs contribute to this reprogramming of gene expression. Among translationally regulated mRNAs, were those encoding proteins involved in DNA methylation as well as in histone methylation and acetylation, suggesting that these epigenetic marks might affect the transcription of specific loci during symbiosis. Recently, we have focused our studies on a histone lysine demethylase (LSD1), which catalyzes oxidative demethylation of di or tri-methylated lysines. LSD1 is subjected to alternative splicing generating two transcript isoforms, a long isoform that encode the functional protein, and a shorter one that encode a truncated protein. The long isoform increases its association to the translational machinery in presence of rhizobia. Currently, we are characterizing the function of this protein during symbiosis as well as the changes in histone methylation in plants with reduced levels of LSD1. These results would provide a better understanding of the epigenetic marks in the reprogramming of gene expression during an agronomically important process such as the BNF.