黄瓜与西芹间作土壤细菌多样性及其对黄瓜枯萎病发生的影响

本试验以黄瓜与西芹间作种植模式为处理,黄瓜单作和西芹单作种植模式为对照,利用Illumina公司Miseq平台对上述不同处理土壤进行16S rDNA细菌群落多样性高通量测序分析和田间接种黄瓜枯萎病菌,探讨黄瓜与西芹间作模式土壤细菌的多样性及其对田间黄瓜枯萎病发生的影响。16S rDNA测序结果表明,黄瓜与西芹间作土壤的细菌物种总数最多,群落多样性水平最高,与对照相比显著提高了土壤细菌observed species指数、Shannon指数和Chao1指数(P0.05);Beta多样性聚类分析表明,黄瓜与西芹间作土壤的环境群落物种与黄瓜单作和西芹单作有一定差异性。在门分类水平上,共检测到45个菌门,其中变形菌门占明显优势,其次为酸杆菌门和放线菌门等;黄瓜与西芹间作土壤细菌种类所占比例最高,达98.63%。在属水平上,共检测到428类菌属,GP6、GP16、GP4、芽单胞菌属、节细菌属5属的丰度值较大;黄瓜与西芹间作土壤的节细菌属分布比例最高,红游动菌属、鞘氨醇单胞菌属和芽球菌属丰度值较大,为黄瓜与西芹间作土壤细菌明显优势菌属。田间接种黄瓜枯萎病菌试验结果表明,采用上述3种不同种植模式土壤种植黄瓜,在黄瓜苗期接种黄瓜枯萎病菌,黄瓜与西芹间作处理的黄瓜枯萎病的田间发病率较西芹单作和黄瓜单作分别降低57.03%~63.54%和66.95%~72.15%。因此,黄瓜与西芹间作增加了土壤细菌群落多样性,降低了黄瓜枯萎病的发病率,对后茬黄瓜土传病害防控具有一定科学指导意义。

Analysis of soil bacterial diversity under cucumber-celery intercropping and its influence on cucumber Fusarium wilt

Cucumber wilt is a soil disease that is highly prevalent in the production and cultivation of cucumber. The disease is highly difficult to prevent and cure. A number of studies have shown that intercropping was one of the most effective methods of reducing the occurrence of plant soil diseases. Also celery has been proven to have high allelopathy. To explore the application of allelopathic effects of celery on cucumber fusarium wilt control, we conducted cucumber and celery intercropping experiment. In the experiment, three planting patterns were set, which were cucumber-celery intercropping, celery monocropping and cucumber monocropping. The cucumber-celery intercropping pattern was regarded as treatment group and monocropping patterns of celery and cucumber regarded as the control group. The Miseq platform of Illumina Company was used to analyze 16S rDNA bacterial community diversity through high-throughput sequencing to discuss the influence of cucumber-celery intercropping on cucumber soil bacterial diversity. Cucumber was planted in soil from different planting patterns and inoculated with Fusarium oxysporium f.sp.cucumerinum (Foc) in the pot experiment to investigate the control effect of cucumber-celery intercropping on cucumber fusarium wilt. The 16S rDNA sequencing results showed that total bacterial species amount and community diversity were highest in soil under cucumber-celery intercropping, which significantly enhanced observed bacteria species index, Shannon index and Chao1 index (P < 0.05). Beta diversity clustering analysis showed there existed a difference in environmental community species between soil from cucumber-celery intercropping and mono-cropped cucumber or celery. Moreover, 15 bacterial phyla were detected. Proteobacteria, which was followed by Acidobacteria and Actinobacteria, had a distinct advantage (35.7%-38.0%). Then the proportion of bacterial species derived from cucumber-celery intercropped soil was highest (98.63%). About 428 bacterial genera were detected with 5 dominant bacterial genera, which were GP6, GP16, GP4, Gemmatimonas and Arthrobacter. Arthrobacter, Rhodoplanes, Sphingomonas and Blastococcus were dominant bacteria genera in cucumber-celery inter-cropped soil. The 4 genera demonstrated that cucumber and celery intercropping enriched the diversity of bacterial communities compared with monocropped celery or cucumber. The results of fusarium wilt inoculation experiment of cucumber suggested that the control efficiency of cucumber-celery intercropping to cucumber fusarium wilt reached 57.03%-63.54% and 66.95%-72.15% relative to monocroped celery and cucumber, respectively. Therefore cucumber-celery intercropping increased the diversity of bacterial communities, and reduced incidence rate of cucumber fusarium wilt. This was of scientific interest for the prevention and control of soil borne diseases.