Submitted to: Kasetsart Journal
Publication Type: Peer reviewed journal
Publication Acceptance Date: 8/12/2003
Publication Date: 11/20/2004
Citation: Thammakijjawat, P., Thaveechai, N., Kositratana, W., Chunwongse, J., Frederick, R.D., Schaad, N.W. 2004. Genetic analysis of Ralstonia solanacearum strains from different hosts in Thailand using PCR-restriction fragment length polymorphism. Kasetsart Journal. 35:397-408. Interpretive Summary: The bacterium Ralstonia solanacearum (RS) causes severe losses in several crops in Thailand and Southeast Asia, including tomato, pepper, potato, and ginger. To determine the diversity among strains of RS from Thailand, 58 strains from Thailand and 50 from 11 other countries were fingerprinted using molecular techniques. Results showed that the 108 strains could be placed into main Groups I and II and minor Groups A through F. Group I contained minor groups A, B, and C and Group II contained minor groups D, E, and F. The Thailand strains from pepper, tomato, ginger, pathumma, and marigold were placed into Group II D. Group II F contained only sesame strains, and Group I B contained strains from potato, only. These results show that the strains of RS from Thailand are diverse and can be fingerprinted for identification.
Technical Abstract: The genetic variability of 58 strains of Ralstonia solanacearum (RS) from Thailand and 50 from all other countries was assessed by restriction fragment length polymorphism (RFLP) assays using primers 759f (5'-GTCGCCGTCAACTCACTTTCC-3') AND 760R (5'-GTCGCCGTCAGCAATGCGGAATCG-3'). An amplified DNA fragment of 281 base pairs was obtained from all RS strains and showed three and five patterns after digested with HaeIII and MspI restriction enzymes, respectively. Six RFLP groups, A, B, C, D, E and F, were designated. Cluster analysis by IPGMA with Dice's coefficient divided the strains into two clusters at 13% similarity. Cluster I contained group A (biovar 1/race 1), group B (biovar 2/race 3) and group C (biovar 1/race 1 and race 2) while cluster II consisted of group D (biovars 3,4/race 1, biovar N2 and the blood disease bacterium, BDB), group E (biovar 1/race 1) and group F (biovars 1,3,4/race 1 and biovar 5/race 5). RS strains of Thailand were mainly typed into race 1 biovars 3 and 4; a few strains from potato in the highlands were typed as race 3 bv2. The strains of race 1 biovar 3 from Thailand could be separated into two groups; D consisted of strains from pepper, tomato and marigold and bv F consisted of strains from sesame. The strains of race 1 bv 4 from ginger and pathumma, and race 3 bv 2 from potato typed into group D and B, respectively. This technique demonstrated the rapid and efficient identification and fingerprinting of strains of RS.