Vlassi Anthi, Nesler Andrea, Parich Alexandra, Puopolo Gerardo, Schuhmacher Rainer
Department of Agrobiotechnology (IFA-Tulln), Institute of Bioanalytics and Agro-Metabolomics, University of Natural Resources and Life Sciences Vienna (BOKU), 3430 Tulln, Austria.
Bi-PA nv (Biological Products for Agriculture), 1840 Londerzeel, Belgium.
Microorganisms. 2020 Nov 9;8(11):1761. doi: 10.3390/microorganisms8111761.
Plant beneficial rhizobacteria may antagonize soilborne plant pathogens by producing a vast array of volatile organic compounds (VOCs). The production of these compounds depends on the medium composition used for bacterial cell growth. Accordingly, AZ78 (AZ78) grown on a protein-rich medium was previously found to emit volatile pyrazines with toxic activity against soilborne phypathogenic fungi and oomycetes. However, the discrepancy between the quantity of pyrazines in the gaseous phase and the minimum quantity needed to achieve inhibition of plant pathogens observed, lead us to further investigate the volatile-mediated inhibitory activity of AZ78. Here, we show that, besides VOCs, AZ78 cells produce ammonia in increased amounts when a protein-rich medium is used for bacterial growth. The production of this volatile compound caused the alkalinization of the physically separated culture medium where was inoculated subsequently. Results achieved in this work clearly demonstrate that VOC, ammonia and the growth medium alkalinization contribute to the overall inhibitory activity of AZ78 against . Thus, our findings suggest that the volatile-mediated inhibitory activity of rhizobacteria in protein-rich substrates can be regarded as a result of multiple factors interaction, rather than exclusively VOCs production.
植物有益根际细菌可通过产生大量挥发性有机化合物（VOCs）来拮抗土传植物病原体。这些化合物的产生取决于用于细菌细胞生长的培养基成分。因此，先前发现生长在富含蛋白质培养基上的AZ78会释放出对土传植物致病真菌和卵菌具有毒性活性的挥发性吡嗪。然而，气相中吡嗪的量与观察到的抑制植物病原体所需的最小量之间的差异，促使我们进一步研究AZ78的挥发性介导的抑制活性。在这里，我们表明，除了VOCs外，当使用富含蛋白质的培养基进行细菌生长时，AZ78细胞会产生更多的氨。这种挥发性化合物的产生导致随后接种的物理分离培养基碱化。这项工作取得的结果清楚地表明，VOC、氨和生长培养基碱化有助于AZ78对……的总体抑制活性。因此，我们的研究结果表明，富含蛋白质底物中根际细菌的挥发性介导抑制活性可被视为多种因素相互作用的结果，而不仅仅是VOCs的产生。
