Genome-Wide Identification of the Gene Family and Functional Validation of and under Abiotic Stress.

Annexins (ANNs) are a structurally conserved protein family present in almost all plants. In the present study, 27 were identified in cotton and were unevenly distributed across 14 chromosomes. Transcriptome data and RT-qPCR results revealed that multiple respond to at least two abiotic stresses. Similarly, the expression levels of and were significantly upregulated under heat, cold, and drought stress. Using virus-induced gene silencing (VIGS), functional characterization of and revealed that, compared with those of the controls, the leaf wilting of -silenced plants was more obvious, and the activities of catalase (CAT), peroxidase (POD), and superoxide dismutase (SOD) were lower under NaCl and PEG stress. Moreover, the expression of stress marker genes (, , , , , , , , , and ) was significantly downregulated in -silenced plants after stress. Under cold stress, the growth of the -silenced plants was significantly weaker than that of the control plants, and the activities of POD, SOD, and CAT were also lower. However, compared with those of the control, the elasticity and orthostatic activity of the -silenced plants were greater; the POD, SOD, and CAT activities were higher; and the , , and expression levels were greater under heat stress. These results suggest that different family members respond differently to different types of abiotic stress.