Assessment of genetic diversity and population structure of Xanthomonas oryzae pv. oryzae with a repetitive DNA element

Abstract

A repetitive DNA element cloned from Xanthomonas oryzae pv. oryzae was used to assess the population structure and genetic diversity of 98 strains ofX. oryzae pv. oryzae collected between 1972 and 1988 from the Philippine Islands. Genomic DNA from X. oryzae pv. oryzae was digested with EcoRI and analyzed for restriction fragment length polymorphisms (RFLPs) with repetitive DNA element as a probe. Twenty-seven RFLP types were identified; there was no overlap of RFLP types among the six races from the Philippines. Most variability (20 RFLP types) was found in strains of races 1, 2, and 3, which were isolated from tropical lowland areas. Four RFLP types (all race 5) were found among strains isolated from cultivars grown in the temperate highlands. The genetic diversity of the total population ofX. oryzae pv. oryzae was 0.93, of which 42% was due to genetic differentiation between races. The genetic diversities of strains collected in 1972 to 1976, 1977 to 1981, and 1982 to 1986, were 0.89, 0.90, and 0.92, respectively, suggesting a consistently high level of variability in the pathogen population over the past 15 years. Cluster analysis based on RFLP banding patterns showed five groupings at 85% similarity. The majority of strains from a given race were contained within one cluster, except for race 3 strains, which were distributed in three of the five clusters.

Genotypic and Pathotypic Diversity of Xanthomonas oryzae pv. oryzae, the Cause of Bacterial Blight of Rice in Punjab State of India

“…However, the characterization of isolates at the molecular level may further help in delineating isolates belonging to the same race or group, studying the pathogenic diversity across the region ⁄ country and monitoring the isolates at the field level. Based on molecular typing, genetic diversity has been reported in the Xoo populations from different rice-growing countries (Leach et al 1992;Nelson et al 1994;Adhikari et al 1995;Ardales et al 1996;George et al 1997;Yashitola et al 1997;Lee et al 1999). In India, the number of reported pathotypes varied from 2 to 11 depending on the number of differential cultivars used (Gupta et al 1986;Reddy and Reddy 1992).…”

Molecular Characterization and Epidemiology of Ralstonia solanacearum Race 3 biovar 2 Causing Brown Rot of Potato in Mauritius

“…oryzae, are used to amplify variable length sequences between copies of the insertion element (George et al 1995;Ochiai et al 2000;Gupta et al 2001;Horita and Tsuchiya 2001;Kaur et al 2005). Leach et al (1992) and Nelson et al (1994) also found that groupings based on this repetitive DNA element (IS1112) were extremely robust and that some phylogenetic lineages could even be related to pathotypes or races. Yun (1991) has reported a relatively high copy number for this insertion element in bacteria, making it an interesting tool to speed up the analysis of a large number of samples in fingerprinting studies.…”

Enhancement of vitamin B6 levels in rice expressing Arabidopsis vitamin B6 biosynthesis de novo genes

“…To test for biotic stress tolerance, wild‐type TP309 and transgenic lines p1300 and 35S ‐12a (that accumulates high levels of vitamin B 6 in leaves) grown under greenhouse conditions were inoculated with two Xanthomonas oryzae pv. oryzae strains, PX071 (Leach et al ., ) and BAI3 (Gonzalez et al ., ), which both cause rice leaf blight. The evaluation of the lesion length 15 days post‐inoculation showed that all wild‐type and the transgenic line 35S ‐12a did not display a statistically significant difference in disease‐related symptoms compared to controls (Figure c).…”