The 5′‐upstream region of WRKY18 transcription factor from banana is a stress‐inducible promoter with strong expression in guard cells

Abstract

Increasing crop productivity in an ever-changing environmental scenario is a major challenge for maintaining the food supply worldwide. Generation of crops having broad-spectrum pathogen resistance with the ability to cope with water scarcity is the only solution to feed the expanding world population. Stomatal closure has implications on pathogen colonization and drought tolerance. Recent studies have provided novel insights into networks involved in stomatal closure which is being used in biotechnological applications for improving crop endurance. Despite that genetic engineering of stomata requires guard cell preferred or specific regulatory regions to avoid undesirable side effects. In the present study, we describe the 5 0 -upstream regulatory region of the WRKY18 transcription factor of banana and functionally analyzed its stress meditated activation and strong guard cell preferred activity. Expression ofMusaWRKY18 is augmented in leaves of banana cultivars Karibale Monthan, Rasthali and Grand Nain under multiple stress conditions suggesting its role in stress responses of banana plants. Transgenic tobacco lines harboring P MusaWRKY18β-D-glucuronidase (GUS) were regenerated and GUS staining demonstrated substantial GUS expression in guard cells which corroborates with multiple Dof1 binding cis-elements in P MusaWRKY18 . Fluorescent β-galactosidase assay demonstrated the stress-mediated strong induction profiles of P MusaWRKY18 at different time points in transgenic tobacco lines exposed to drought, high-salinity, cold, and applications of abscisic acid, salicylic acid, methyl jasmonate, and ethephon. This study sheds novel insights into guard cell preferred expression of WRKY genes under stress and confirm the utility of P MusaWRKY18 for exploring guard cell functions and guard cell engineering.

Identification of the WRKY Gene Family and Characterization of Stress-Responsive Genes in Taraxacum kok-saghyz Rodin

“…WRKY stress-related cis -elements play critical roles in several plant processes under ever-changing environmental conditions by regulating the plant complex defense signal transduction pathways [ 53 ]. WRKY TFs interacted with the cis -elements downstream of gene promoters to regulate the expression of target gene and caused a series of responses, consequently enhancing the resistance to stress of plants [ 49 , 54 , 55 , 56 , 57 ]. WRKY transcription factors can recognize and bind w-box elements to regulate the expression of downstream genes [ 4 ].…”

Identification and Characterization of WRKY41, a Gene Conferring Resistance to Powdery Mildew in Wild Tomato (Solanum habrochaites) LA1777

“…Ectopic overexpression of Capsicum annum WRKY27 confers resistance to Ralstonia solanacearum in Nicotiana tabacum through modulation of SA-, JA-and ET-mediated signaling pathways [53]. MusaWRKY18, from banana, P MusaWRKY18 -β-D-glucuronidase (GUS) assay reveals that the expression of MusaWRKY18 is strongly induced after application of abscisic acid, SA, methyl jasmonate, and ethephon, which indicates that plant hormones SA and Eth can induce the expression of MusaWRKY18 [54]. MiWRKY53, identified from mulberry (Morus indica var.…”

Molecular Pathways of WRKY Genes in Regulating Plant Salinity Tolerance

“…This sub-genome labeling has been conserved due to its significance within the context of renaming here. In addition, musaWRKY18 does not follow standard naming conventions [140] nor does WRKY75 [120].…”