Proteomics analysis revealed the activation and suppression of different host defense components challenged with mango leaf spot pathogen Alternaria alternata.

Background: Mango is an economically important fruit tree in many regions of the world, but is highly susceptible to mango leaf spot disease, caused by Alternaria species. How to manage this disease has been a challenge and therefore understanding the regulation of host molecular components in response to pathogen infection is necessary. In this study, we conducted a comprehensive proteomic analysis of mango leaves upon inoculation with the leaf spot pathogen A. alternata.

Results: Determination of enzyme activity revealed a significant accumulation of cell-wall degrading enzymes cellulase and β-Glucosidase in pathogen inoculated mango leaves. A total of 472 differentially expressed proteins (DEPs) were detected in the proteome data with significant up-regulation of GO terms associated with response to fungus infection. The significantly downregulated proteins during pathogen invasion and colonization were involved in the photosynthesis, phenylpropanoid, flavonoid biosynthesis, and phenylalanine metabolism pathway. The significantly upregulated proteins belonged to tyrosine metabolism and MAPK signalling pathway, signifying their crucial role in host resistance to leaf spot pathogen.

Conclusion: Our finding provide useful data on differential expression of proteins for designing novel management strategies to specifically target mango host defense components to achieve the best control of leaf spot disease in mango.