Proteomic analysis reveals dynamic expression related to malondialdehyde in cassava in response to cassava bacterial blight.

Cassava bacterial blight (CBB) significantly affects cassava production in Thailand. Understanding tolerant cultivar responses can reveal key disease resistance mechanisms. This study identified differentially abundant proteins between the tolerant 'Rayong72' (R72) and susceptible 'Hanatee' (HN) cassava cultivars, with quantitative PCR validating mRNA-level changes. Several upregulated proteins in the R72 cultivar were linked to disease progression and defense mechanisms. Correlations between phenotypic symptoms, including malondialdehyde (MDA) levels and protein expression trends, were observed. A higher MDA level, associated with cell damage, correlated with severe symptoms in the HN at the infection site. However, in R72, despite higher MDA levels in leaves compared to HN, oxidative stress-related proteins were also upregulated. Notably, proteins involved in NAD/NADP biosynthesis (QNS), glutathione-based redox regulation (GSS), and MAPK signaling (MAPKKK18) were enriched in the tolerant cultivar, suggesting distinct reactive oxygen species (ROS) regulation and contributing to differential resistance. Taken together, these findings highlight the role of MDA and coenzyme-related proteins in cassava's defense responses to bacterial infections, emphasizing their importance in stress regulation. This study provides molecular insights into cassava-CBB interactions and underscores the potential of proteomic analysis in advancing plant disease resistance research as well as aiding breeding programs.