Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, Bari, Italy.
Istituto per la Protezione Sostenibile delle Piante, Consiglio Nazionale delle Ricerche, Portici, Italy.
Microb Biotechnol. 2023 Dec;16(12):2292-2312. doi: 10.1111/1751-7915.14311. Epub 2023 Jul 18.
The construction of microbial consortia is challenging due to many variables to be controlled, including the cross-compatibility of the selected strains and their additive or synergistic effects on plants. In this work, we investigated the interactions in vitro, in planta, and at the molecular level of two elite biological control agents (BCAs), that is Streptomyces microflavus strain AtB-42 and Trichoderma harzianum strain M10, to understand their attitude to cooperate in a consortium. In vitro, we observed a strong cross-antagonism between AtB-42 and M10 in agar plates due to diffusible metabolites and volatile organic compounds. In liquid co-cultures, M10 hindered the growth of AtB-42 very likely because of secondary metabolites and strong competition for the nutrients. The interaction in the co-culture induced extensive transcriptional reprogramming in both strains, especially in the pathways related to ribosomes, protein synthesis, and oxidoreductase activity, suggesting that each strain recognized the counterpart and activated its defence responses. The metabolome of both strains was also significantly affected. In contrast, in the soil, M10 growth was partially contrasted by AtB-42. The roots of tomato seedlings inoculated with the consortium appeared smaller than the control and single-strain-inoculated plants, indicating that plants diverted some energy from the development to defence activation, as evidenced by the leaf transcriptome. The consortium induced a stronger transcriptional change compared to the single inoculants, as demonstrated by a higher number of differentially expressed genes. Although the cross-antagonism observed in vitro, the two strains exerted a synergistic effect on tomato seedlings by inducing resistance responses stronger than the single inoculants. Our observations pose a question on the usefulness of the sole in vitro assays for selecting BCAs to construct a consortium. In vivo experiments should be preferred, and transcriptomics may greatly help to elucidate the activity of the BCAs beyond the phenotypic effects on the plant.
由于需要控制许多变量，包括所选菌株的交叉兼容性及其对植物的附加或协同作用，因此微生物群落的构建具有挑战性。在这项工作中，我们研究了两种优秀的生物防治剂（BCA），即链霉菌微黄色菌株 AtB-42 和哈茨木霉菌株 M10，在体外、体内和分子水平上的相互作用，以了解它们在群落中的合作态度。在体外，我们观察到 AtB-42 和 M10 在琼脂平板上由于可扩散代谢物和挥发性有机化合物而表现出强烈的交叉拮抗作用。在液体共培养物中，M10 很可能由于次生代谢物和对营养物质的强烈竞争而阻碍 AtB-42 的生长。共培养物中的相互作用诱导了两种菌株广泛的转录重编程，特别是与核糖体、蛋白质合成和氧化还原酶活性相关的途径，这表明每种菌株都识别了对应的菌株并激活了其防御反应。两种菌株的代谢组也受到了显著影响。相比之下，在土壤中，AtB-42 部分抑制了 M10 的生长。用群落接种的番茄幼苗的根比对照和单菌株接种的植物小，表明植物从发育中转移了一些能量用于防御激活，这可以通过叶片转录组来证明。与单一接种剂相比，群落诱导了更强的转录变化，表现为更多差异表达基因。尽管在体外观察到交叉拮抗作用，但两种菌株通过诱导比单一接种剂更强的抗性反应对番茄幼苗产生协同作用。我们的观察对仅在体外测定中选择 BCA 构建群落的有用性提出了疑问。应该优先进行体内实验，并且转录组学可以极大地帮助阐明 BCA 的活性，超越对植物的表型影响。
