Proteomic analysis of salicylic acid enhanced disease resistance in bacterial wilt affected chilli (Capsicum annuum) crop

- Bacterial wilt disease caused by R.solanacearum severely reduces the yield of C. annum cultivars thereby it drastically effects the global food market
- SA acts as an abiotic elicitor it significantly elevates the defense system against pathogen
- Proteomic study reveals us that the higher expression of stress related proteins, defense related proteins and proteins involving in degradation pathways plays a crucial role in developing bacterial wilt resistance.

Salicylic acid (SA) is an important endogenous chemical signal that plays a key role in enhancing plant defense responses. Exogenous application of 0.5 mM SA for 3 days enhanced resistance to bacterial wilt (BW) disease (by reduction in disease incidence level upto 64% under greenhouse conditions) without any detrimental effect on plant growth. To understand the dynamics of protein in SA-primed chilli during BW infection, proteomic approach using 2DE-SDS PAGE was performed. Proteomic analysis revealed 25 differentially expressed proteins (which were more prominent in SA primed-challenge inoculated chilli samples), of which 20 were successfully identified by Nano-LC MS/MS analysis. The differential expression pattern revealed that proteins associated with stress and defense, energy and metabolism, protein synthesis, protein destination and storage and transcription related were upregulated indicating the involvement of SA induced disease resistance in chilli seedlings. This suggests the complexity of the proteome and inter-connected pathways responsible for SA induced resistance in chilli. Correlation in the differential expression of catalase and EF-1A from proteomic as well as semiquantitative RT-PCR suggests this probable use as biomarkers in screening susceptibility of chilli cultivars for wilt disease. Findings from this study will serve as basis for designing disease-management strategies based on resistance conferred by SA, which could applicable to other biotic stress affected staple crops.