Distribution and diversity of endophytic bacteria in tomato plants from Guangxi
广西番茄内生细菌的多样性和数量动态

Study of the distribution and fluctuation of endophytic bacteria in tomato plants is important for screening of specific endophytic bacteria strains to control bacterial wilt of tomato. We isolated 624 endo-phytic bacteria strains from the roots, stems and leaf tissues of 303 symptomless tomato plants collected from Guangxi. By conventional methods, these strains were identified as Bacillus, Pseudomonas, Xanthomonas, Microbacterium, Corynebacterium, Erwinia, Enterobacter, and Agrobacterium. Among them, Bacillus, Pseudomonas, and Agrobacterium were main genera and Bacillus was the dominant genus. The endophytic bacteria were the most common in the roots of tomato plants, followed by those in stems and leaves. The to-tal amount of endophytic bacteria increased gradually from the seedling stage to flowering stage, and then decreased gradually from fruit setting stage to ripening stage. The amount of most endophytic bacteria genera fluctuated in correspondence with the total amount of endophytic bacteria with the exception of Microbacte-rium, whose number kept decreasing from seedling to ripening stages. More endophytic bacteria were found in tomato plants cultivated in the spring than those cultivated in the autumn.