Identification And Salinity-tolerance Analysis Of The LOG Gene Family In G.hirsutum L.

Cytokinin is an important plant hormone that promotes plant cell division,differentiation,and participates in salt response under osmotic stress.Cytokinin-Activating Enzymes,LOGs(LONELY GUY)are involved in cytokinin synthesis.However,there has been no comprehensive characterization of LOG gene family in cotton.In this study we identified 151 LOG genes from nine plant species,including 28 LOG genes in G.hirsutum).Phylogenetic analysis divided LOG genes into three groups.Further,exons/introns 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.hirsutumwith purification 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 cell membrane.Virus-induced gene silencing(VIGS)of GhLOG3_At in cotton enhanced sensitivity of plants to salt stress with increased malondialdehyde(MDA)contents and decreased catalase(CAT)and proline(PRO)activity.Physiological analysis indexes were consistent with salt stress phenotype.Our result suggested that GhLOG3_At induces salt stress tolerance in cotton,andprovide basis for the use of cytokinin synthesis genes to regulate cotton growth and stress resistance.