USDA-ARS, U.S. Salinity Laboratory, Riverside, California 92507, USA.
J Environ Sci Health B. 2010 Jul;45(5):427-36. doi: 10.1080/03601231003800131.
Rhizosphere and phyllosphere microbial communities were evaluated on roots and leaves of growth chamber-grown lettuce (Lactuca sativa (L.) cv. Green Forest) plants by culture-dependent and -independent methods after soil fumigation. Denaturing gradient gel electrophoresis (DGGE) with 16S rRNA primers followed by cloning and sequencing was used to identify major rRNA bands from the rhizosphere and phyllosphere. Three weeks after fumigation, there were no differences (P = 0.16) in rhizosphere microbial communities between the fumigated treatments and the control. The same effect was observed during week seven after fumigation (P=0.49). Also, no significant differences (P=0.49) were found in the phyllosphere microbial communities between the fumigated treatments and the control during the growth period of the plant. A majority of the bands in the rhizosphere were related to known bacterial sequences with a 96 to 100 % sequence similarity. Some of the derived sequences were related to Pseudomonas syringae pv. tomato DC300 and Bradyrhizobium japonicum USDA 110. A total of 23 isolates were identified from leaf surface by both culture-dependent and independent methods, and only Photorhabdus luminescens was found on leaf surface using both techniques. All the Biolog isolates from phyllosphere were from the Proteobacteria phylum compared to the culture-independent bands from the leaves that were from different bacterial phyla. Based on our data, methyl bromide (MeBr) and methyl iodide (MeI) did not have any significant negative effects on rhizosphere and phyllosphere microbial communities throughout the growing period of lettuce.
根际和叶际微生物群落采用培养依赖和独立方法，在土壤熏蒸后对生长室中生长的生菜（Lactuca sativa (L.) cv. Green Forest）植物的根和叶进行了评估。用 16S rRNA 引物进行变性梯度凝胶电泳（DGGE），然后进行克隆和测序，用于鉴定根际和叶际的主要 rRNA 带。熏蒸后 3 周，熏蒸处理与对照之间的根际微生物群落没有差异（P = 0.16）。熏蒸后 7 周也观察到相同的效果（P = 0.49）。此外，在植物生长期间，叶际微生物群落中，熏蒸处理与对照之间也没有发现显著差异（P = 0.49）。根际中的大多数带与已知细菌序列具有 96%至 100%的序列相似性。一些衍生序列与丁香假单胞菌 pv.番茄 DC300 和大豆根瘤菌 USDA 110 有关。通过培养依赖和独立方法共从叶面分离出 23 个菌株，仅用光杆菌（Photorhabdus luminescens）两种技术都在叶面上发现。与叶际的非培养独立带相比，叶际的所有 Biolog 分离株均来自变形菌门。根据我们的数据，甲基溴（MeBr）和甲基碘（MeI）在整个生菜生长期间对根际和叶际微生物群落没有任何显著的负面影响。
