Ren Gaidi, Ma Yan, Guo Dejie, Gentry Terry J, Hu Ping, Pierson Elizabeth A, Gu Mengmeng
Institute of Agricultural Resources and Environment, Jiangsu Academy of Agricultural Sciences, Nanjing, China.
Key Laboratory of Agro-Environment in Downstream of Yangtze Plain, Ministry of Agriculture, Nanjing, China.
Front Microbiol. 2018 Feb 13;9:185. doi: 10.3389/fmicb.2018.00185. eCollection 2018.
Application of Brassicaceous seed meal (BSM) is a promising biologically based disease-control practice but BSM could directly and indirectly also affect the non-target bacterial communities, including the beneficial populations. Understanding the bacterial response to BSM at the community level is of great significance for directing plant disease management through the manipulation of resident bacterial communities. wilt is a devastating disease on pepper. However, little is known about the response of bacterial communities, especially the rhizosphere bacterial community, to BSM application to soil heavily infested with wilt pathogen and cropped with peppers. In this study, a 25-day microcosm incubation of a natural wilt pathogen-infested soil supplemented with three BSMs, i.e., 'Crantz' (CAME), 'Pacific Gold' (PG), and a mixture of PG and cv. 'IdaGold' (IG) (PG+IG, 1:1 ratio), was performed. Then, a further 35-day pot experiment was established with pepper plants growing in the BSM treated soils. The changes in the bacterial community in the soil after 25 days of incubation and changes in the rhizosphere after an additional 35 days of pepper growth were investigated by 454 pyrosequencing technique. The results show that the application of PG and PG+IG reduced the disease index by 100% and 72.8%, respectively, after 35 days of pepper growth, while the application of CAME did not have an evident suppressive effect. All BSM treatments altered the bacterial community structure and decreased the bacterial richness and diversity after 25 days of incubation, although this effect was weakened after an additional 35 days of pepper growth. At the phylum/class and the genus levels, the changes in specific bacterial populations resulting from the PG and PG+IG treatments, especially the significant increase in Actinobacteria-affiliated and an unclassified genus and the significant decrease in Chloroflexi, were suspected to be one of the microbial mechanisms involved in PG-containing BSM-induced disease suppression. This study is helpful for our understanding of the mechanisms that lead to contrasting plant disease severity after the addition of different BSMs.
应用十字花科种子粕（BSM）是一种很有前景的基于生物学的病害防控措施，但BSM也可能直接或间接影响非靶标细菌群落，包括有益菌群。在群落水平上了解细菌对BSM的反应对于通过调控本地细菌群落来指导植物病害管理具有重要意义。青枯病是辣椒上一种毁灭性病害。然而，对于细菌群落，尤其是根际细菌群落，对在严重感染青枯病病原菌且种植辣椒的土壤中施用BSM的反应知之甚少。在本研究中，对添加了三种BSM（即‘Crantz’（CAME）、‘Pacific Gold’（PG）以及PG与‘IdaGold’品种（IG）的混合物（PG + IG，1:1比例））的天然感染青枯病病原菌的土壤进行了25天的微观培养。然后，开展了一项为期35天的盆栽试验，让辣椒植株在经BSM处理的土壤中生长。通过454焦磷酸测序技术研究了培养25天后土壤中细菌群落的变化以及辣椒再生长35天后根际的变化。结果表明，在辣椒生长35天后，施用PG和PG + IG分别使病情指数降低了100%和72.8%，而施用CAME没有明显的抑制作用。所有BSM处理在培养25天后均改变了细菌群落结构，降低了细菌的丰富度和多样性，尽管在辣椒再生长35天后这种影响有所减弱。在门/纲和属水平上，PG和PG + IG处理导致的特定细菌种群变化，尤其是放线菌属相关菌和一个未分类属的显著增加以及绿弯菌门的显著减少，被认为是含PG的BSM诱导病害抑制所涉及的微生物机制之一。本研究有助于我们理解添加不同BSM后导致植物病害严重程度不同的机制。
