Abstract
Xanthomonas campestris pv. campestris phages (3 isolates of phage S, K and '76) were isolated from black rot diseased leaves of cabbage, cauliflower and turnip, and some of their fundamental properties were investigated. The particle of phage S was tadpole-like with a polyhedral head of about 50×60 nm and a tail of about 110×10 to 12 nm. Phages S and K attacked specifically X. campestris pv. campestris, but not X. campestris pv. citri, pv. cucurbitae, pv. oryzae, pv. phaseoli and pv. pruni. Phages S and K showed different host range to bacterial isolates of X. campestris pv. campestris. The thermal inactivation point of phage S was 53 C in distilled water and 65 C in potato ring-rot liquid medium by 10 min incubation. Phage S was more stable in its lytic activity in potato ring-rot liquid medium or in phosphate buffer than in distilled water. Phage S was also stable at pH 7.0, but not at pH 4.9 or 9.1. Throughout all conditions of different three dispersants and five pH levels phage S was more stable at 5 C than at 28 C. One-step growth experiments showed that multiplication of phage '76 was optimal at 28 C. The latent period, rise period and average burst size in the case of single infection were 75 min, 40 min and 13 plaque forming units, respectively. At 30 C or at the temperatures below 26 C, however, the latent period was prolonged and the average burst size became smaller.
