Enhanced drought and salt stress tolerance in Arabidopsis via ectopic expression of the PvMLP19 gene.

Key message: PvMLP19 overexpression in Arabidopsis enhances proline accumulation, mitigates oxidative stress, improves water retention, delays germination, and stimulates root growth under drought and salt stress conditions. Climate change has exacerbated the frequency and severity of drought and salinity stress, posing significant risks to agricultural productivity and food security. As sessile organisms, plants have evolved regulatory mechanisms to adapt to these challenges. Common bean (Phaseolus vulgaris L.), an essential legume crop valued for its high nutritional value, is increasingly impacted by climate change-induced stressors. The PR10 protein family has been recognized as a potential contributor to enhancing plant resilience to abiotic and biotic stresses. This family, also known as Bet v1, is highly conserved and consists of diverse subfamilies, including major latex proteins (MLPs), which may contribute to stress tolerance through ligand-binding and regulation of stress-related pathways. This study aimed to investigate the functional role of PvMLP19 in stress tolerance using both in silico and experimental approaches. RNA-seq analysis revealed tissue-specific expression patterns of PR10s, with PvMLP19 showing notable induction under abiotic stress. Functional validation in transgenic Arabidopsis suggested that overexpression of PvMLP19 may improve drought tolerance. Transgenic plants exhibited increased proline accumulation, reduced oxidative stress, and higher relative water content under both drought and salinity stress conditions. Furthermore, PvMLP19 overexpression was associated with delayed seed germination but promoted root development under osmotic and salinity stress. The increased stress tolerance was linked to the upregulation of stress-inducible genes, suggesting a potential regulatory role of PvMLP19 in modulating stress-response pathways. These findings position PvMLP19 as a potential candidate for genetic improvement in crops, offering a promising strategy to mitigate the impacts of climate change and ensure sustainable agricultural productivity.