Programa de Ecologia Genómica, Centro de Ciencias Genómicas, UNAM, Cuernavaca, Mexico.
Bioengineered. 2013 Jul-Aug;4(4):236-43. doi: 10.4161/bioe.23808. Epub 2013 Jul 2.
It has been documented that bacteria from the Burkholderia genera produce different kinds of compounds that inhibit plant pathogens, however in Burkholderia tropica, an endophytic diazotrophic and phosphate-solubilizing bacterium isolated from a wide diversity of plants, the capacity to produce antifungal compounds has not been evaluated. In order to expand our knowledge about Burkholderia tropica as a potential biological control agent, we analyzed 15 different strains of this bacterium to evaluate their capacities to inhibit the growth of four phytopathogenic fungi, Colletotrichum gloeosporioides, Fusarium culmorum, Fusarium oxysporum and Sclerotium rolffsi. Diverse analytical techniques, including plant root protection and dish plate growth assays and gas chromatography-mass spectroscopy showed that the fungal growth inhibition was intimately associated with the volatile compounds produced by B. tropica and, in particular, two bacterial strains (MTo293 and TTe203) exhibited the highest radial mycelial growth inhibition. Morphological changes associated with these compounds, such as disruption of fungal hyphae, were identified by using photomicrographic analysis. By using gas chromatography-mass spectroscopy technique, 18 volatile compounds involved in the growth inhibition mechanism were identified, including α-pinene and limonene. In addition, we found a high proportion of bacterial strains that produced siderophores during growth with different carbon sources, such as alanine and glutamic acid; however, their roles in the antagonism mechanism remain unclear.
已有文献记载，伯克霍尔德氏菌属的细菌能产生多种抑制植物病原体的化合物，然而，在从多种植物中分离出的内生固氮和溶磷细菌热带伯克霍尔德氏菌中，其产生抗真菌化合物的能力尚未得到评估。为了拓展我们对作为潜在生物防治剂的热带伯克霍尔德氏菌的认识，我们分析了该细菌的 15 个不同菌株，以评估它们抑制四种植物病原菌（炭疽菌、禾谷镰刀菌、尖孢镰刀菌和罗耳伏革菌）生长的能力。多种分析技术，包括植物根系保护和培养皿生长测定以及气相色谱-质谱联用分析表明，真菌生长抑制与热带伯克霍尔德氏菌产生的挥发性化合物密切相关，特别是两个细菌菌株（MTo293 和 TTe203）表现出最高的径向菌丝生长抑制。通过使用显微摄影分析，鉴定了与这些化合物相关的形态变化，如真菌菌丝的破坏。通过使用气相色谱-质谱联用技术，鉴定出 18 种参与生长抑制机制的挥发性化合物，包括α-蒎烯和柠檬烯。此外，我们发现许多细菌菌株在利用不同碳源（如丙氨酸和谷氨酸）生长时会产生铁载体，但其在拮抗机制中的作用仍不清楚。
