Genome-wide identification and expression analysis of the HVA22 gene family in cotton and functional analysis of in drought and salt tolerance.

The HVA22 family of genes, induced by abscisic acid and stress, encodes a class of stress response proteins with a conserved TB2/DP1/HVA22 domain that are unique among eukaryotes. Previous studies have shown that play an important role in plant responses to abiotic stresses. In the present study, 34, 32, 16, and 17 were identified in , , , and , respectively. These genes were classified into nine subgroups, randomly distributed on the chromosomes. Synteny analysis showed that the amplification of the were mainly due to segmental duplication or whole genome replication (WGD). Most promoter sequences contain a large number of drought response elements (MYB), defense and stress response elements (TC-rich repeats), and hormone response elements (ABRE, ERE, SARE, etc.), suggesting that may respond to adversity stresses. Expression profiling demonstrated that most showed a constitutive expression pattern in and could respond to abiotic stresses such as salt, drought, and low temperature. Overexpression of () in enhances salt and drought tolerance in Arabidopsis. Virus-induced gene silencing of reduced salt and drought tolerance in cotton. This indicates that plays an active role in the plant response to salt stress and drought stress. may act in plant response to adversity by altering the antioxidant capacity of plants. This study provides valuable information for the functional genomic study of the HVA22 gene family in cotton. It also provides a reference for further elucidation of the functional studies of HVA22 in plant resistance to abiotic stress response.