Rhizoctonia solani is a broad spectrum fungal pathogen that infects crops in greenhouse and field conditions causing plants damping-off and fruit rot which provoke serious yield losses. This study prospected the use of bacterial volatile organic compounds (VOCs) to control R. solani infection on tomato seedlings and fruit in order to search for an alternative to the use of chemical pesticides. Seed-born bacterial endophytes were isolated from the cultivated Solanum lycopersicum and the wild Solanum linnaeanum species. This study showed a host- and organ-specific colonization of endophytic bacteria at early seedling stage with most of them colonizes the cotyledons in comparison to stems and roots. Overall, 51 % and 11 % of isolated endophytic bacteria produce antifungal VOCs against R. solani at 7 d and 14 d of dual culture, respectively. The majority (about 78 %) of the antagonistic bacterial endophytes showed promoting activity on tomato seedling growth. For the bioprotection tests the strains TRC7 and TRC10 of Bacillus subtilis and TRT11 of B. megateriumwere selected as the most antagonistic and PGP endophytic bacteria and a non-antagonistic strain SMLR7 of Paenibacillus sp., with this later strain reported for the first time colonizing internal seed tissues of S. linnaeanum. The VOCs of the strain TRC7 showed the best pattern of decrease of R. solani rotting on tomato fruit, and increase the hypocotyl length, the radicle length, the fresh weight, and the vigor of tomato seedlings. The identification of the VOCs produced by the antagonistic Bacillus strains showed a core set of four compounds i.e. 2-Heptanone; Pyrazine, 2,5-dimethyl-; Naphthalene; and Benzenamine, N-ethyl- which was the most abundant. All the four VOCs showed antifungal activity against R. solani in vitro growth, and to our knowledge this activity is reported for the first time for Benzenamine, N-ethyl- and 2-Heptanone. The Benzenamine, N-ethyl- showed the best antifungal activity with an IC50 about 0.09 mL L⁻¹ headspace and proved to be effective in reducing R. solani rotting on tomato fruit at the same concentration. So, this work provides evidence about VOCs-mediated biocontrol ability of Bacillus strains to reduce R. solani seedling damping-off and fruit rot of tomato making them valuable agents for pre- and postharvest control of this disease.

立枯丝核菌是一种广谱真菌病原体，它感染温室和田间条件下的作物，导致植物猝倒和果实腐烂，造成严重的产量损失。本研究展望了使用细菌挥发性有机化合物 (VOC) 来控制番茄幼苗和果实上的茄病菌感染，以寻找使用化学杀虫剂的替代方法。从栽培的番茄和野生的茄属植物中分离出种子生细菌内生菌物种。该研究表明，与茎和根相比，内生细菌在幼苗早期的宿主和器官特异性定植，其中大多数定植于子叶。总体而言，在双重培养的第 7天和第14 天，分别有51% 和 11% 的分离出的内生细菌产生抗真菌的 VOC 。大多数（约 78%）拮抗性细菌内生菌显示出对番茄幼苗生长的促进活性。对于生物保护测试菌株的TRC7和TRC10枯草芽孢杆菌和TRT11巨大芽孢杆菌被选定为最拮抗和PGP内生细菌和非拮抗菌株SMLR7类芽孢杆菌sp.，此后的菌株首次被报道定植于S. linnaeanum 的内部种子组织。应变TRC7的挥发性有机化合物显示出减少的最佳模式纹枯病菌腐烂上番茄果实，增加胚轴长度，胚根长度，鲜重，和番茄幼苗活力。拮抗芽孢杆菌菌株产生的挥发性有机化合物的鉴定显示出一组核心的四种化合物，即2-庚酮；吡嗪，2,5-二甲基-；萘；和苯胺，N-乙基-这是最丰富的。所有四种 VOC 均显示出对R. solani 的抗真菌活性体外生长，据我们所知，这是首次报道苯胺、N-乙基和 2-庚酮的这种活性。的苯胺，N-乙基-显示出最好的抗真菌活性与约0.09毫升升的IC 50 ^-1的顶部空间，并证明是有效地减少纹枯病菌腐烂上番茄果实在相同的浓度。因此，这项工作提供了关于芽孢杆菌菌株的VOC 介导的生物防治能力的证据，以减少茄属植物幼苗猝倒和番茄果实腐烂，使它们成为收获前和收获后防治该病害的重要试剂。