Molecular characterisation of Malaysian rice germplasm for bacterial blight

Abstract

Bacteria blight caused by Xanthomonas oryzae pv oryzae is one of the most destructive bacterial diseases of rice among the biotic stress that occurring worldwide. This disease is a significant constraint to food security in Asia, which cause yield loss in rice. Therefore, there is an urgent need for controlling bacterial blight disease through resistance cultivars. However, the genetic potential of Malaysian rice cultivar has not yet been investigated. Hence, present study was conducted to screen the presence and absence of resistance genes in 38 of modern cultivated Malaysian varieties using thirteen Simple Sequences Repeats (SSR) markers and one Sequence Tagged Sites (STS) marker. Rice cultivar MRQ74 had maximum 10 resistance genes while MR81 had only one resistance gene. However, MR263 and MR84 did not exhibits any resistance gene. Among the Malaysian rice varieties, the highest resistance level was observed in RM317 locus while the lowest resistance level was found in RM21 locus. Amplified product specific to xa13 is not detected. A dendrogram was constructed to classify 38 Malaysian rice varieties into seven major clusters at 0.0, 0.25 and 0.3 of similarity coefficient. MR84 and MR263 were formed in cluster 1 and cluster 2 alone. Both varieties were the least genetic related to other Malaysian cultivars because they do not possess any resistance gene. Cluster 5 was the largest group comprised of ten rice cultivars. Rice cultivars carrying multiple resistance genes was grouped in cluster 5. The result can be served as the source of parent donor gene for gene pyramiding through marker-assisted selection and select appropriate parent cultivars for hybridization programmes to develop cultivars possessing durable resistance against bacterial blight.