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′-upstream regulatory region of the WRKY18 transcription factor of banana and functionally analyzed its stress meditated activation and strong guard cell preferred activity. Expression of MusaWRKY18 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_MusaWRKY18-β-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.

中文翻译：

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来自香蕉的 WRKY18 转录因子的 5'-上游区域是一个应激诱导型启动子，在保卫细胞中具有强表达

在不断变化的环境中提高作物生产力是维持全球粮食供应的一项重大挑战。生产具有广谱病原体抗性和应对缺水能力的作物是养活不断扩大的世界人口的唯一解决方案。气孔关闭对病原体定植和耐旱性有影响。最近的研究为涉及气孔关闭的网络提供了新的见解，该网络正用于生物技术应用以提高作物耐力。尽管气孔的基因工程需要保卫细胞首选或特定的调节区域，以避免不良副作用。在本研究中，我们描述了WRKY18的 5'-上游调控区域香蕉的转录因子，并对其应激冥想激活和强大的保卫细胞首选活性进行了功能分析。在多种胁迫条件下，香蕉品种Karibale Monthan、Rasthali和Grand Nain 的叶子中MusaWRKY18 的表达增加，表明其在香蕉植物的胁迫反应中的作用。携带P _MusaWRKY18 - β-D-葡萄糖醛酸酶 ( GUS ) 的转基因烟草品系得到再生，GUS 染色表明保卫细胞中有大量GUS表达，这证实了P _{MusaWRKY18 中}多个结合Dof1 的顺式元件. 荧光 β-半乳糖苷酶测定表明，在暴露于干旱、高盐度、寒冷和脱落酸、水杨酸、茉莉酸甲酯和乙烯利的转基因烟草品系的不同时间点，P _MusaWRKY18的胁迫介导强诱导谱。这项研究揭示了压力下WRKY基因的保卫细胞优先表达的新见解，并证实了P _MusaWRKY18在探索保卫细胞功能和保卫细胞工程方面的效用。