Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, 2–24–16, Naka-cho, Koganei, Tokyo 184–8588, Japan.
Microbes Environ. 2010;25(2):83-94. doi: 10.1264/jsme2.me09171.
The effect of four amino acids, unutilizable by Ralstonia solanacearum, on tomato bacterial wilt (TBW) was tested in three Japanese soils. Results confirmed our previous findings that the addition (2.5 mg g(-1) soil) of lysine and serine suppressed TBW, but that of tyrosine and valine did not. The number of the pathogen in non-rhizosphere soil, rhizosphere soil and the rhizoplane was markedly lower in the lysine and serine treatments than in the tyrosine and valine treatments, while the opposite result was obtained for the total bacterial population. Substrate-induced respiration analysis revealed that bacteria became more predominant in the amino acid treatments, especially in lysine. There were no apparent correlations between the microbial activities in soil and the disease index. PCR-DGGE targeting the 16S rRNA gene of the rhizoplane samples from lysine-added Nagoya, Fuchu and Iwate soils revealed 10, 1 and 2 unique bands, respectively, indicating shifts in bacterial community. DGGE patterns in the suppressive treatments belonged to the same cluster while the not suppressive treatments clustered differently. The lower disease incidence of TBW following lysine treatment is likely related to a specific bacterial community in the rhizoplane that developed on the addition of lysine.
四种精氨酸合成酶缺陷型罗尔斯通氏菌不能利用的氨基酸对番茄青枯病的影响在三种日本土壤中进行了测试。结果证实了我们之前的发现，即添加（2.5mg g(-1) 土壤）赖氨酸和丝氨酸可抑制番茄青枯病，但添加酪氨酸和缬氨酸则不能。在非根际土壤、根际土壤和根际表面，添加赖氨酸和丝氨酸处理组的病原菌数量明显低于添加酪氨酸和缬氨酸处理组，而总细菌种群则相反。基质诱导呼吸分析表明，在氨基酸处理组中，细菌更为优势，尤其是在赖氨酸处理组中。土壤中的微生物活性与疾病指数之间没有明显的相关性。针对来自添加赖氨酸的名古屋、府中和岩手土壤的根际表面样本的 16S rRNA 基因的 PCR-DGGE 显示，分别有 10、1 和 2 个独特的条带，表明细菌群落发生了变化。抑制性处理的 DGGE 模式属于同一聚类，而非抑制性处理的聚类则不同。添加赖氨酸后，番茄青枯病发病率降低可能与赖氨酸添加后在根际表面形成的特定细菌群落有关。
