Plant defense elicitor, 2, 4-dichloro-6-{(E)-[(3-methoxyphenyl) imino] methyl} phenol (DPMP) and its mode of action against fungal pathogen Alternaria solani in tomato (Solanum lycopersicum L.)

Abstract

Biotic stress factors are one of the major constraints plants face, anthey significantly affect production and yield. There are multiple ways to copwith stress factors, including genetic enhancement. When they cannot providsufficient protection, pesticides are commonly applied. Plant defense elicitors ara new approach for boosting plants' natural immune responses and toleranclevels. The newly identified promising plant defense elicitor; 2, 4-dichloro-6{(E)-[(3-methoxyphenyl) imino] methyl} phenol (DPMP) was previously studieagainst the oomycete Hyaloperonospora arabidopsidis, the bacterial pathogenPseudomonas syringae and Clavibacter michiganensis ssp michiganensis anfound to induce disease resistance against these phytopathogens. However, it wanot tested against fungal pathogens. Here for the first time, DPMP was evaluateagainst one of the most destructive fungal pathogens, Alternaria solani. Diseasseverity and plant development were evaluated. The results revealed that DPMneither inhibited nor enhanced the disease severity of A. solani. Gene expressioof several salicylic acid, jasmonic acid, and ethylene pathway-related genes (Pti4TPK1b, Pto kinase, PRB1‐2, SABP2, and PR3) were also analyzed. According tthe results, while DPMP induces PRB1-2, TPK1b, and Pto kinase genexpressions, the protection against A. solani does not occur via these genes. PRis one of the most important genes for defense responses against necrotrophipathogens, and DPMP downregulated gene expression of PR3. These resultdemonstrated that DPMP mostly takes a role through the SA-related defenspathway and was effective against biotrophic and hemibiotrophic pathogensHowever, it is not suitable for protection against the necrotrophic pathogen Asolani. Further research may pinpoint the activity of DPMP on the defenspathway and provide a better understanding of the mode of action for DPMP another plant elicitors for specific plant protection solutions.