A Soybean bZIP Transcription Factor GmbZIP19 Confers Multiple Biotic and Abiotic Stress Responses in Plant

The basic leucine zipper (bZIP) is a plant-specific transcription factor family that plays crucial roles in response to biotic and abiotic stresses. However, little is known about the function of bZIP genes in soybean. In this study, we isolated a bZIP gene,GmbZIP19, from soybean. A subcellular localization study ofGmbZIP19revealed its nucleus localization. We showed thatGmbZIP19expression was significantly induced by ABA (abscisic acid), JA (jasmonic acid) and SA (salicylic acid), but reduced under salt and drought stress conditions. Further,GmbZIP19overexpressionArabidopsislines showed increased resistance toS. sclerotiorumandPseudomonas syringaeassociated with upregulated ABA-, JA-, ETH- (ethephon-)and SA-induced marker genes expression, but exhibited sensitivity to salt and drought stresses in association with destroyed stomatal closure and downregulated the salt and drought stresses marker genes' expression. We generated a soybean transientGmbZIP19overexpression line, performed a Chromatin immunoprecipitation assay and found that GmbZIP19 bound to promoters of ABA-, JA-, ETH-, and SA-induced marker genes in soybean. The yeast one-hybrid verified the combination. The current study suggested thatGmbZIP19is a positive regulator of pathogen resistance and a negative regulator of salt and drought stress tolerance.