广西番茄内生细菌的多样性和数量动态

为了探明内生细菌在番茄中的分布和数量变化规律,有目的地筛选防治番茄青枯病的内生细菌,我们对广西可培养的番茄内生细菌的类群和数量动态进行了调查。从广西部分县市采集的303个番茄样本中分离到624株内生细菌菌株,初步确定有芽孢杆菌(Bacillus)、假单胞菌(Pseudomonas)、黄单胞菌(Xanthomonas)、棒杆菌(Corynebacterium)、土壤杆菌(Agrobacterium)、微杆菌(Microbacterium)、肠杆菌(Enterobacter)和欧文氏菌(Erwinia)8个属,其中以芽孢杆菌、假单胞菌和土壤杆菌为芽孢杆菌为优势类群。番茄内生细菌在植株器官中的分布以根部数量最多,其次是茎和叶。内生细菌的总量在番茄生育期的变化趋势是从苗期到花期数量上升,而从结果期到成熟期数量逐渐下降。多数内生细菌种群的数量变化动态符合细菌总量的变化趋势,只有微杆菌在番茄植株整个生育期中始终保持下降的趋势。春季种植的番茄植株的内生细菌类群数量比秋季种植的少。

Distribution and diversity of endophytic bacteria in tomato plants from Guangxi

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.