Understanding Differential Expression of PvLEA, a Drought Responsive Gene in Common Bean (Phaseolus vulgaris L.)

Drought is a persistent problem in agriculture and it is important to better understand its effect on plant growth and development. Common bean (Phaseolus vulgaris L.) is an important food legume, which provides a steady source of dietary protein and fiber. Our interest is in understanding the regulation of drought- responsive genes in common bean. In this work, the expression of the drought-responsive gene, PvLEA, was studied. Common bean cultivar Sierra, was selected and treated with two water stress conditions (100% and 25% field capacity) from planting to plant maturity. Soil moisture content was measured accurately and treatments were given when the moisture content in drought-treated plants was below 5%.  Effects of drought was studied by: a) collecting plant tissue (roots, stems, leaves, flowers, and pods) at different developmental stages (2, 2.5, 3, 4, 5, 6, 7, and 8 weeks after planting;  b) using bioinformatics tools to search for potential drought-responsive gene sequences  followed by designing primers, and c) amplification of cDNA derived from drought treated and non-drought plant tissue with PvLEA primers to detect differential gene expression. Our work showed that drought affects common bean, physically, around two to four weeks of treatment. Additionally, differential expression of PvLEA in root tissue was seen as early as four weeks of treatment with gene expression higher in drought roots. We also examine PvLEA gene expression on the  stems, leaves, flowers, and pods of the drought and non-treated plants.