Abstract:

Bacillus subtilis strain TR21 mutant of resistant streptomycin 300 μg/ml was acquired by continuously screening on series concentration of streptomycin media, compared with original strain, whose antagonism against pathogen of banana wilt disease and colony morphology weren’t changed. The colonization of marked strain in banana plant, root surface and rhizosphere soil was investigated with inoculations of injuring root, drenching root and dropping leaf axil. The results showed that the marked strain could colonize and transfer in banana tissues when inoculated by injuring root and drenching root methods, and there was the most amount in the banana plant after injuring root inoculation, 1 d after inoculation, the population of marked strain were 3.33×106 cfu?g-1 in corm of banana; the marked strain also displayed good colonization in the rhizosphere soil and root surface, 15 d after inoculation, the population of marked strain in root surface were 6.18×103 cfu?g-1 or 5.53×103 cfu?g-1, respectively, and in the rhizosphere soil were 1.13×104 cfu?g-1 or 1.04×104 cfu?g-1, respectively; with these two inoculation methods, the population of marked strain showed the downward trend generally in banana plant, root surface and rhizosphere soil during 1 to 15 d after inoculation; inoculated by dropping leaf axil method, the marked strain could only colonize in leaf, the population showed a trend “first increasing then decreasing”.