Saline-alkali is one important abiotic stressor influencing tomato production. Exogenous MeJA is well known to increase tomato resistance to a variety of stresses, although its exact mechanism is yet unknown. In this study, we confirmed that 22.5 μmol/L MeJA could significantly improve the saline-alkali stress resistance of tomato. 300 mM saline-alkali stress increased the endogenous MeJA and JA content in tomato by 18.8% and 13.4%, respectively. Exogenous application of 22.5 μmol/L MeJA increased the endogenous MeJA and JA content in tomato by 15.2% and 15.9%, respectively. Furthermore, we found an important transcription factor SlWRKY80 wihch respond to MeJA, and constructed its overexpressed and knockout lines through genetic transformation. It was found that SlWRKY80 actively regulated tomato resistance to saline-alkali stress, and the spraying of exogenous MeJA (22.5 μmol/L) reduced the sensitivity of SlWRKY80 knockout lines to saline-alkali stress. The SlWRKY80 protein directly combines with the promoter of SlSPDS2 and SlNHX4 to positively regulate the transcription of SlSPDS2 and SlNHX4, thereby promoting the synthesis of spermidine and Na+/K+ homeostasis, actively regulate saline-alkali stress. The augmentation of JA content led to a notable reduction of 70.6% in the expression of SlJAZ1, the SlWRKY80 protein interacting with SlJAZ1 is released. In conclusion, we revealed the mechanism of exogenous MeJA in tomato stress resistance through multiple metabolic pathways, elucidated that exogenous MeJA further promotes spermidine synthesis and Na+/K+ homeostasis by activating the expression of SlWRKY80, which provided a new theoretical basis for the study of JA stress resistance mechanism and the actual production of tomato.

中文翻译：

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SlWRKY80介导的JA途径通过提高亚精胺含量和稳定Na+/K+稳态来正向调节番茄对盐碱胁迫的抵抗力

盐碱是影响番茄生产的重要非生物胁迫源。众所周知，外源 MeJA 可以提高番茄对多种胁迫的抵抗力，但其确切机制尚不清楚。本研究证实22.5 μmol/L MeJA可显着提高番茄的盐碱胁迫抗性。300 mM盐碱胁迫使番茄内源MeJA和JA含量分别增加18.8%和13.4%。外源施用22.5 μmol/L MeJA使番茄内源MeJA和JA含量分别增加15.2%和15.9%。此外，我们还发现了一个对MeJA有反应的重要转录因子SlWRKY80，并通过遗传转化构建了其过表达和敲除株系。研究发现，SlWRKY80主动调控番茄对盐碱胁迫的抗性，喷施外源MeJA（22.5 μmol/L）降低了SlWRKY80敲除株系对盐碱胁迫的敏感性。SlWRKY80蛋白直接与SlSPDS2和SlNHX4的启动子结合，正向调控SlSPDS2和SlNHX4的转录，从而促进亚精胺的合成和Na+/K+稳态，主动调节盐碱胁迫。JA含量的增加导致SlJAZ1的表达显着降低70.6%，与SlJAZ1相互作用的SlWRKY80蛋白被释放。总之，我们通过多种代谢途径揭示了外源MeJA在番茄抗逆性中的作用机制，阐明外源MeJA通过激活SlWRKY80的表达进一步促进亚精胺合成和Na+/K+稳态，为JA的研究提供了新的理论基础。番茄抗逆机制与实际生产.