Evaluation of banana cultivars and the pathogenesis-related class 3 and 10 proteins in defense against Ralstonia syzygii subsp. celebesensis, the causal agent of banana blood disease

Banana blood disease (BBD), caused by Ralstonia syzygii subsp. celebesensis ( Rsc ), is a major threat to banana production in Southeast Asia. This study aimed to assess the resistance of cultivated and wild banana accessions to Rsc and investigate the expression of patho-genesis-related (PR) protein genes, namely PR3 and PR10 , in disease-resistant bananas. Bacterial isolates were isolated from infected bananas in Yala Province, Thailand, and their pathogenicity and phylotype were confirmed, along with Rsc -specific PCR. Rsc -resistance banana screening was conducted on 16 banana accessions, including cultivated and wild types, using representative Rsc isolates. ‘Khai Kasetsart 2’ exhibited resistance (R), followed by ‘Raksa’ with moderate resistance (MR). The expression of PR3 and PR10 genes was analyzed in the resistant ‘Khai Kasetsart 2’ and susceptible ‘Hin’ bananas, revealing distinct expression patterns. PR3 showed rapid upregulation on day 1 after inoculation (DAI), while PR10 exhibited sustained upregulation from 1 to 7 DAI in the resistant cultivar. These findings indicate the involvement of PR proteins in the defense response against Rsc and hold promise for future breeding and disease management strategies in bananas.