• Research in Plant Disease
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• v.6 no.1
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• pp.10-14
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• 2000

In 1998, bacterial shot hole of peach (Prunus persica) and Japanese plum(Prunus salicina) was found in Naju and Milyang. Five isolates of bacteria isolates from the diseased leaves and fruits of peach and Japanese plum were classified into genus Erwinia and Xanthomonas on diagnostic characteristics. Of five isolates, two were identified as X. campestris pv. pruni, three as E. nigrifluens. E.nigrifluens is the first description of bacteria which causes the disease on peach and Japanese plum in Korea. the symptoms caused by E. nigrifluens were hardly distinguished from those caused by X. campestris pv. pruni. In addition, it was observed that two pathogenic bacteria were isolated from most of naturally infected plants at the same time. from the reason mentioned above, we proposed to use a single common name \"bacterial shot hole of peach and Japanese plum\" for the both bacterial diseases, hereafter.

• Korean Journal Plant Pathology
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• v.13 no.3
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• pp.179-183
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• 1997

We have screened hypersensitive responses of 18 cultivars of Nicotiana tabacum to Xanthomonas campestris pv. campestris. TC500 cultivar produced the most strong hypersensitive response (HR) to Xanthomonas campestris pv. campestris. By NTG mutagenesis, nonhypersensitive mutants (XHN 514-774, XHN 620-831) were generated, which does not induce hypersensitive response on tobacco leaves (Nicotiana tabacum cv. TC500). Also nonpathogenic mutant (XPN 1001), which does not incite any of the black rot symptoms on leaves was generated. We observed that HR mutants were still pathogenic on cabbage leaves producing black rot symptoms and nonpathogenic mutant induced HR in tobacco leaves. The inplanta growth of wild type and HR mutants were examined for up to 120 hrs after inoculation : population of wild type strain increased to $10^{8}$ in 24hrs, but rapidly declined thereafter; HR-mutants increased to more than $10^{6}$ in 48 hrs after inoculation but subsequently stabilized and slowly decreased. We observed that wild type and these mutans produced similar amounts of degradative enzymes such as protease, pectate lyase, cellulase and amylase.

• Korean Journal Plant Pathology
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• v.2 no.3
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• pp.150-157
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• 1986

Effects of presservation methods on viability and virulence of Xanthosmonas compestris pv. oryzae were investigated. The incidence of colony-type variants from freeze-dried and deep-frozen cultures was also determined. The suspending medium for freeze-dried cultures containing $10\%$ sucrose and $1\%$ gelatin showed the highest viability, and the virulence was well maintained in the suspending medium containing $2\%$ dextrin, $0.5\%$ ascorbic acid, 0.5% ammonium chloride, $0.5\%$ thiourea, and $0.85\%$ NaCl. Serially transferred cultures became attenuated. Rough colonies which had wrinkled surface occurred at a frequency of $1.9\%$ to $15.8\%$ during freeze-drying and freezing. The rough colonies consisted of nonseptated filamentous cells and rod-shaped cells. The virulence of rough colonies was weak as compared with the normal colony type.