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The APETALA2 (AP2)/ethylene response factor plays vital functions in response to environmental stimulus. The ethylene response factor (ERF) subfamily B3 group belongs to the AP2/ERF superfamily and contains a single AP2/ERF domain. Phylogenetic analysis of the ERF subfamily B3 group genes from Arabdiposis thaliana, Gossypium arboreum, Gossypium hirsutum , and Gossypium raimondii made it possible to divide them into three groups and showed that the ERF subfamily B3 group genes are conserved in cotton. Collinearity analysis identified172 orthologous/paralogous gene pairs between G. arboreum and G. hirsutum ; 178 between G. hirsutum and G. raimondii ; and 1,392 in G. hirsutum. The GhERF subfamily B3 group gene family experienced massive gene family expansion through either segmental or whole genome duplication events, with most genes showing signature compatible with the action of purifying selection during evolution. Most G. hirsutum ERF subfamily B3 group genes are responsive to salt stress. GhERF13.12 transgenic Arabidopsis showed enhanced salt stress tolerance and exhibited regulation of related biochemical parameters and enhanced expression of genes participating in ABA signaling, proline biosynthesis, and ROS scavenging. In addition, the silencing of the GhERF13.12 gene leads to increased sensitivity to salt stress in cotton. These results indicate that the ERF subfamily B3 group had remained conserved during evolution and that GhERF13.12 induces salt stress tolerance in Arabidopsis and cotton. [ABSTRACT FROM AUTHOR]

• GhZAT family genes play an important role in cotton stress resistance. • 44 GhZAT genes were identified in G. hirsutum. • 16 GhZAT genes generally responded to NaCl and ABA stress. • GhZAT6 play an important role in salt resistance of cotton. High salt environments can induce stress in different plants. The genes containing the ZAT domain constitute a family that belongs to a branch of the C 2 H 2 family, which plays a vital role in responding to abiotic stresses. In this study, we identified 169 ZAT genes from seven plant species, including 44 ZAT genes from G. hirsutum. Phylogenetic tree analysis divided ZAT genes in six groups with conserved gene structure, protein motifs. Two C 2 H 2 domains and an EAR domain and even chromosomal distribution on At and Dt sub-genome chromosomes of G. hirsutum was observed. GhZAT6 was primarily expressed in the root tissue and responded to NaCl and ABA treatments. Subcellular localization found that GhZAT6 was located in the nucleus and demonstrated transactivation activity during a transactivation activity assay. Arabidopsis transgenic lines overexpressing the GhZAT6 gene showed salt tolerance and grew more vigorously than WT on MS medium supplemented with 100 mmol NaCl. Additionally, the silencing of the GhZAT6 gene in cotton plants showed more obvious leaf wilting than the control plants, which were subjected to 400 mmol NaCl treatment. Next, the expressions of GhAPX1 , GhFSD1 , GhFSD2 , and GhSOS3 were significantly lower in the GhZAT6- silenced plants treated with NaCl than the control. Based on these findings, GhZAT6 may be involved in the ABA pathway and mediate salt stress tolerance by regulating ROS-related gene expression. [ABSTRACT FROM AUTHOR]

Cytokinin (CK) is an important plant hormone that promotes plant cell division and differentiation, and participates in salt response under osmotic stress. LOGs (LONELY GUY) are CK-activating enzymes involved in CK synthesis. The LOG gene family has not been comprehensively characterized in cotton. In this study we identified 151 LOG genes from nine plant species, including 28 LOG genes in Gossypium hirsutum. Phylogenetic analysis divided LOG genes into three groups. Exon/intron structures and protein motifs of GhLOG genes were highly conserved. Synteny analysis revealed that several gene loci were highly conserved between the A and D sub-genomes of G. hirsutum with purifying selection pressure during evolution. Expression profiles showed that most LOG genes were constitutively expressed in eight different tissues. Furthermore, LOG genes can be regulated by abiotic stresses and phytohormone treatments. Moreover, subcellular localization revealed that GhLOG3_At resides inside the cell membrane. Overexpression of GhLOG3 enhanced salt tolerance in Arabidopsis. Virus-induced gene silencing (VIGS) of GhLOG3_At in cotton enhanced sensitivity of plants to salt stress with increased H 2 O 2 contents and decreased chlorophyll and proline (PRO) activity. Our results suggested that GhLOG3_At induces salt stress tolerance in cotton, and provides a basis for the use of CK synthesis genes to regulate cotton growth and stress resistance. • This study identified 151 LOG genes, including 28 LOG genes in G. hirsutum. • Gene loci were highly conserved between the A and D sub-genomes of G. hirsutum. • LOG genes can be regulated by abiotic stresses and phytohormone treatments. • Overexpression of GhLOG3 enhanced salt tolerance in Arabidopsis. • VIGS of GhLOG3_At in cotton enhanced sensitivity of plants to salt stress. [ABSTRACT FROM AUTHOR]