Tomato(Solanum lycopersicum)is an important crop but frequently experiences saline-alkali stress.Our previous studies have shown that exogenous spermidine(Spd)could significantly enhance the saline-alkali resistance o...Tomato(Solanum lycopersicum)is an important crop but frequently experiences saline-alkali stress.Our previous studies have shown that exogenous spermidine(Spd)could significantly enhance the saline-alkali resistance of tomato seedlings,in which a high concentration of Spd and jasmonic acid(JA)exerted important roles.However,the mechanism of Spd and JA accumulation remains unclear.Herein,SIWRKY42,a Group II WRKY transcription factor,was identified in response to saline-alkali stress.Overexpression of SIWRKY42 improved tomato saline-alkali tolerance.Meanwhile,SIWRKY42 knockout mutants,exhibited an opposite phenotype.RNA-sequencing data also indicated that SIWRKY42 regulated the expression of genes involved in JA signaling and Spd synthesis under saline-alkali stress.SIWRKY42 is directly bound to the promoters of SISPDS2 and SINHX4 to promote Spd accumulation and ionic balance,respectively.SIWRKY42 interacted with SIMYC2.Importantly,SIMYC2 is also bound to the promoter of SISPDS2to promote Spd accumulation and positively regulated saline-alkali tolerance.Furthermore,the interaction of SIMYC2 with SIWRKY42 boosted SIWRKY42's transcriptional activity on SISPDS2,ultimately enhancing the tomato's saline-alkali tolerance.Overall,our findings indicated that SIWRKY42 and SIMYC2 promoted saline-alkali tolerance by the Spd biosynthesis pathway.Thus,this provides new insight into the mechanisms of plant saline-alkali tolerance responses triggered by polyamines(PAs).展开更多
基金support from the Scientific&Technological Innovative Research Team of Shaanxi Province(Grant No.2021TD-34)the China Agriculture Research System(Grant No.CARS-23-D06)the National Natural Science Foundation of China(Grant No.32302531)。
文摘Tomato(Solanum lycopersicum)is an important crop but frequently experiences saline-alkali stress.Our previous studies have shown that exogenous spermidine(Spd)could significantly enhance the saline-alkali resistance of tomato seedlings,in which a high concentration of Spd and jasmonic acid(JA)exerted important roles.However,the mechanism of Spd and JA accumulation remains unclear.Herein,SIWRKY42,a Group II WRKY transcription factor,was identified in response to saline-alkali stress.Overexpression of SIWRKY42 improved tomato saline-alkali tolerance.Meanwhile,SIWRKY42 knockout mutants,exhibited an opposite phenotype.RNA-sequencing data also indicated that SIWRKY42 regulated the expression of genes involved in JA signaling and Spd synthesis under saline-alkali stress.SIWRKY42 is directly bound to the promoters of SISPDS2 and SINHX4 to promote Spd accumulation and ionic balance,respectively.SIWRKY42 interacted with SIMYC2.Importantly,SIMYC2 is also bound to the promoter of SISPDS2to promote Spd accumulation and positively regulated saline-alkali tolerance.Furthermore,the interaction of SIMYC2 with SIWRKY42 boosted SIWRKY42's transcriptional activity on SISPDS2,ultimately enhancing the tomato's saline-alkali tolerance.Overall,our findings indicated that SIWRKY42 and SIMYC2 promoted saline-alkali tolerance by the Spd biosynthesis pathway.Thus,this provides new insight into the mechanisms of plant saline-alkali tolerance responses triggered by polyamines(PAs).
