Studies on the Mechanism of 'Kresek' Induction of Rice Plant Caused by Xanthomonas oryzae (Uyeda & Ishiyama) Dowson

벼 위조형 흰빛잎마름병의 발병기작에 관한 연구

The study has been carried out to investigate the mechanism of 'Kresek' induction caused by Xanthomonas oryzae (Uyeda & Ishiyama) Dowson. The results are summarized as follows: 1. K-isolate could always induce 'Kresek' symptom on susceptible varieties when the pathogenic bacteria were introduced either way through the leaves or roots, while N-isolate could not induce. 2. Milyang 23 which showed 'Kresek' symptom had significantly smaller diameter of vessel elements than those of other two varieties examined. 3. The bacterial number of It-isolates in the extract of Milyang 23 was higher than N-isolates but there was no difference in bacterial number between K-and N-isolates when they were grown in the extract of Tongil. 4. N and K-isolates reached to death phase after 3 days and 9 days, respectibly, when they were grown in the extract of Milyang 23. Both isolates, however, reached to death phase at the same time after 3 days of incubation in the extract of Tonsil. 5. Heavy precipitation was observed in the extract of Milyang 23 at PH 3.0-4.0 range, while only traceable precipitation could be observed in the extract of Tongil at the same pH range under room temperature.

1. "Kresek" 유발균주(K균주)는 품종에 따라서 발현에 차이가 있었으며 지상부 또는 지하부에 접종하여도 "Kresek"을 유발시킬 수 있었으나 대조균주(N균주)는 전연 유발되지 않았다. 2. 엽백의 도관직경은 밀양 23이 유신이나 통일보다 현저히 작았으며 이들간에 고도의 통계적인 유의차가 인정되었다. 3. 밀양 23의 즙액에서 K균주들은 N균주들보다 세균의 증식이 왕성하였으며 통일에서는 균주들간에 증식의 차이가 없었다. 4. 밀양 23의 즙액친서는 K균주의 Dead phase가 정종 9일째부터 N균주는 4일째부터 시작되었으며 통일에서는 모두 3일째부터 시작되었다. 5. 밀양 23즙액의 경우 pH 3.0-4.0 범위에서 다량의 침전물이 형성되었으나 동일의 증액에서는 극히 소량의 침전물을 관찰할 수가 있었다.