嗜线虫致病杆菌SN313的次生代谢产物及其抑制植物病原真菌活性研究

通过化学与生物活性筛选从土壤中分离得到一株菌株，利用16S rDNA方法将其鉴定为嗜线虫致病杆菌Xenorhabdus nematophila并命名为SN313。采用微生物发酵、液相萃取、柱层析及半制备高效液相色谱等技术，对SN313的发酵液进行分离纯化，得到3个化合物。利用质谱和核磁共振等波谱技术并依据文献数据确定了这3个化合物分别是N-(2-羟基苯基乙酰) 色胺 ( 1 )、吩嗪-1-羧酸 ( 2 ) 和环(脯氨酸-色氨酸) ( 3 )，其中化合物 1 是一个新的β-吲哚基乙胺类衍生物。通过微量稀释法测定了3个化合物对4种植物病原真菌的抑制活性。结果表明:化合物 1 对辣椒疫霉Phytophthoa capsici和番茄灰霉病菌Botrytis cinerea具有明显的抑制作用 (IC₅₀值分别为11.20 μg/mL和28.94 μg/mL)；化合物 2 对番茄灰霉病菌、辣椒疫霉、水稻纹枯病菌Thanatephorus cucumeris和小麦根腐病菌Bipolaris sorokiniana有明显的抑制作用 (IC₅₀ < 40 μg/mL)；化合物 3 对番茄灰霉病菌具有较好的抑制效果 (IC₅₀ = 41.58 μg/mL)。从土壤微生物中获取化合物 2 ，为生物农药申嗪霉素有效成分的天然获取提供了一种新的途径。

Secondary metabolites of Xenorhabdus nematophila SN313 and their inhibitory activities against plant pathogenic fungi

A strain from a soil sample was obtained by screening of chemical and biological activities. This strain was identified as Xenorhabdus nematophila using 16S rDNA method and it was named as SN313. The fermented broth of SN313 was isolated and purified using microorganism fermentation, liquid extraction, column chromatography, high performance preparative liquid chromatography and other techniques. Three compounds were obtained and identified as N-(2-hydroxyphenylacetyl) tryptamine ( 1 ), phenazine-1-carboxylic acid ( 2 ), cyclo(Pro-Trp) ( 3 ) based on the results of MS, NMR and published literatures. Compound 1 is a new derivative of β-indolyl ethylamine. Mycelium growth rate method was performed to determine the antifungal activities of the three compounds. The results showed that compound 1 significantly inhibited the growth of Phytophthoa capsici and Botrytis cinerea (IC₅₀ values were 11.20 μg/mL and 28.94 μg/mL, respectively). Compound 2 had significant inhibitive effect agianst B. cinerea, P. capsici, Thanatephorus cucumeris and Bipolaris sorokiniana (IC₅₀ < 40 μg/mL). And compound 3 could inhibit the growth of B. cinerea (IC₅₀ = 41.58 μg/mL). Of note, isolation of compound 2 from soil microorganism provides a new natural source of phenazine-1-carboxylic acid.