Avirulence gene diversity of Xanthomonas axonopodis pv. glycines isolated in Korea.
The hybridization patterns with the avrBs3 gene that is known to determine the recognition of host specificity were used to study the diversity of Xanthomonas axonopodis pv. glycines causing bacterial leaf pustule in soybean. A total of 155 strains were isolated from diverse tissues of soybean cultivars collected in Korea and were classified into six different type strains of OcsF, SL1017, SL1018, SL1045, SL1157, and SL2098 according to the patterns of avrBs3-homologous bands. When these type strains were inoculated on various cultivars, most of the Korean strains mildly induced disease symptoms on the resistant CNS1 cultivars. Unlike other type strains, strain SL2098, which appeared not to contain any avrBs3 homolog, induced only a few pustules on even highly susceptible cultivars. When a plasmid carrying the 3.7-kb avrBs3-homologous gene from strain SL1045 was introduced into SL2098, the transformant could not recover the pathogenicity in susceptible host plants. However, when avrBs3-homologous genes of strain SL1018 were mutated by transposon mutagenesis, one of the mutants in which a 5.2-kb chromosomal band homologous to avrBs3 was disrupted could not induce the hypersensitive response on resistant cultivars such as William82 or CNS2. Our results suggest that the avrBs3 homologs may play important roles in the pathogenicity of Xanthomonas axonopodis pv. glycines and the recognition of soybean cultivars.
Division of Plant Pathology, National Institute of Agricultural Science and Technology, Rural Development Administration, Suwon 441-707, Korea.
Hyoung-Joon
HJ
Park
Sang-Wook
SW
Han
Changsik
C
Oh
Seungdon
S
Lee
Dongsoo
D
Ra
Suk-Ha
SH
Lee
Sunggi
S
Heu
D001426:Bacterial Proteins / Q000235:genetics; D002874:Chromosome Mapping / Q000379:methods; D055028:Comparative Genomic Hybridization / Q000379:methods; D004251:DNA Transposable Elements; D005798:Genes, Bacterial; D014644:Genetic Variation; D015698:Genomic Library; D007723:Korea; D016296:Mutagenesis; D010641:Phenotype; D010935:Plant Diseases / Q000382:microbiology*; D018515:Plant Leaves / Q000382:microbiology; D013025:Glycine max / Q000382:microbiology; D053532:Xanthomonas axonopodis / Q000145:classification / Q000235:genetics* / Q000302:isolation & purification / Q000472:pathogenicity*
D001426:Bacterial Proteins; D004251:DNA Transposable Elements