Abstract：
TGA-binding (TGA) transcription factors, characterized by the basic region/leucine zipper motif (bZIP), have been recognized as pivotal regulators in plant growth, development, and stress responses through their binding to the as-1 element. In this study, the TGA gene families in melon, watermelon, cucumber, pumpkin, and zucchini were comprehensively characterized, encompassing analyses of gene/protein structures, phylogenetic relationships, gene duplication events, and cis-acting elements in gene promoters. Upon transient expression in Nicotiana benthamiana, the melon CmTGAs, with typical bZIP and DOG1 domains, were observed to localize within the nucleus. Biochemical investigation revealed specific interactions between CmTGA2/3/5/8/9 and CmNPR3 or CmNPR4. The CmTGA genes exhibited differential expression patterns in melon plants in response to different hormones like salicylic acid, methyl jasmonate, and ethylene, as well as a fungal pathogen, Stagonosporopsis cucurbitacearum that causes gummy stem blight in melon. The overexpression of CmTGA3, CmTGA8, and CmTGA9 in Arabidopsis plants resulted in the upregulation of AtPR1 and AtPR5 expression, thereby imparting enhanced resistance to Pseudomonas syringae pv. Tomato DC3000. In contrast, the overexpression of CmTGA7 or CmTGA9 resulted in a compromised resistance to Botrytis cinerea, coinciding with a concomitant reduction in the expression levels of AtPDF1.2 and AtMYC2 following infection with B. cinerea. These findings shed light on the important roles of specific CmTGA genes in plant immunity, suggesting that genetic manipulation of these genes could be a promising avenue for enhancing plant immune responses.
摘要：
TGA结合（TGA）转录因子，以碱性区域/亮氨酸拉链基序（bZIP）为特征，被认为是植物生长的关键调节剂，发展,以及通过它们与as-1元素的结合而产生的应激反应。在这项研究中,甜瓜中的TGA基因家族，西瓜,黄瓜,南瓜,西葫芦的特征全面，包括基因/蛋白质结构的分析，系统发育关系，基因复制事件，和基因启动子中的顺式作用元件。在烟草中瞬时表达，甜瓜CmTGA，具有典型的bZIP和DOG1域，被观察到位于细胞核内。生化研究揭示了CmTGA2/3/5/8/9与CmNPR3或CmNPR4之间的特定相互作用。CmTGA基因在甜瓜植物中表现出差异表达模式，以响应不同的激素，如水杨酸，茉莉酸甲酯,和乙烯，以及真菌病原体，南瓜孢霉，引起甜瓜胶质茎枯病。CmTGA3，CmTGA8和CmTGA9在拟南芥植物中的过表达导致AtPR1和AtPR5表达上调，从而赋予对丁香假单胞菌pv的增强的抗性。番茄DC3000。相比之下,CmTGA7或CmTGA9的过表达导致对灰葡萄孢菌的抗性受损，与感染灰白杆菌后AtPDF1.2和AtMYC2的表达水平同时降低相吻合。这些发现揭示了特定CmTGA基因在植物免疫中的重要作用。表明对这些基因的遗传操作可能是增强植物免疫反应的有希望的途径。
