GpEF1A: a novel lysine methyltransferase gene from Gypsophila perfoliata L. involved in boron homeostasis.

Rapid accumulation of boron (B) leads to toxicity in plant tissues, and the narrow gap between deficiency and toxicity makes it difficult to adjust essential B levels in soil for plant productivity. Therefore, understanding different aspects of B tolerance is necessary to provide new and valid solutions to B toxicity. Gypsophila perfoliata stands out as a remarkable example of a B-tolerant plant, with a natural propensity to thrive in environments such as B mines and soils enriched with high levels of B. In this study, a yeast functional screening experiment was conducted using cDNA libraries from G. perfoliata leaf and root cells for B tolerance. Ten colonies from the leaf library grew in 80 mm boric acid, while none emerged from the root library. Analysis of isolated cDNAs showed identical sequences and a unique motif related to B tolerance. The gene GpEF1A was identified in the tolerant yeast colonies, with predicted structural features suggesting its role, and RT-qPCR indicating increased expression under B stress. A regulatory role for EF1A lysine methylation was proposed in mammalian cells and fungi because of its dynamic and inducible nature under environmental constraints. This could also be relevant for plant cells, as the high similarity of the GpEF1A gene in some salt-tolerant plants might indicate the upregulation of EF1A as a conserved way to cope with abiotic stress conditions. This report represents the first instance of involvement of GpEF1A in B tolerance, and further detailed studies are necessary to understand other components of this tolerance mechanism.