Genome-Wide Analysis of Cellulose Synthase Superfamily and Roles of GmCESA1 in Regulating Drought Tolerance and Growth of Soybean

The cellulose synthase (CS) superfamily, comprising the cellulose synthase (CESA) and cellulose synthase-like (CSL) families, plays crucial roles in plant response to abiotic stresses, growth and development. However, there are few reports on the biological functions of CSs in soybean. In this study, 80 soybean CS members were identified and classified into seven subfamilies. Collinearity analyses revealed that the segmental duplication is likely the primary driver for the expansion of CS superfamily in soybean. The abundant stress-responsive and growth-related <i>cis</i>-acting elements in the promoter regions of soybean <i>CS</i> genes suggest their potential functions. Notably, <i>GmCESA1</i> exhibited significantly higher expression levels in drought-tolerant soybean under drought stress. Soybean plants with lower <i>GmCESA1</i> expression via virus-induced gene silencing (VIGS-<i>GmCESA1</i>) were less drought-tolerant than the control plants (VIGS-EV), showing reduced relative water content and dry weight than VIGS-EV under drought stress. Furthermore, VIGS-<i>GmCESA1</i> soybean plants displayed reduced plant height under both well-watered and drought-stressed conditions. Our findings highlight that <i>GmCESA1</i> has pleiotropic functions in regulating both drought tolerance and growth in soybean, contributing to our knowledge on CS and providing a valuable gene to breed drought-tolerant soybean in the future.