Biocontrol agents promote growth of potato pathogens, depending on environmental conditions.
Biocontrol agents promote growth of potato pathogens, depending on environmental conditions.
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DOI：
10.1111/1751-7915.12349
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发表时间：
2016-05
影响因子：
5.7
通讯作者：
Hallsworth JE
中科院分区：
文献类型：
--
作者：
Cray JA;Connor MC;Stevenson A;Houghton JD;Rangel DE;Cooke LR;Hallsworth JE
迫切需要了解和优化生物防治，以避免过度依赖可能损害环境和人类健康的合成化学农药。本研究重点研究了生防新菌株芽孢杆菌之间的相互作用。JC12GB43、马铃薯致病疫霉和镰刀菌。在体外和马铃薯块茎上进行的检测中，该细菌能够几乎完全抑制病原菌。该芽孢杆菌具有足够的耐旱性(生长的水分活度极限为0.928)，表现优于致病疫霉(~0.960)，并向生长窗口下限挑战蓝镰刀菌(~0.847)和三叶镰刀菌(~0.860)。然而，在某些条件下，菌株JC12GB43能刺激病原菌的增殖：例如，在体外共沸条件下(132 mM尿素)，蓝色镰刀菌的生长速度提高了100%，在块茎上(2-M甘油)的生长速度提高了570%。以培养为基础的检测包括大分子稳定(共渗)相容的溶质，提供了原理证明，在破坏真菌细胞大分子系统的条件下，芽孢杆菌可以为植物病原菌提供共渗代谢产物。虽然这是史无前例的，但这一发现与早期的报告一致，即真菌可以利用来自细菌细胞的代谢物。除非在所有与田间相关的参数上对候选生防菌的抗菌活性进行检测，否则生防剂可能会促进植物病原菌的侵染，从而降低作物产量。因此，这些发现表明，生物防治活动应被视为一种行为模式(取决于当时的条件)，而不是细菌菌株的固有属性。
There is a pressing need to understand and optimize biological control so as to avoid over‐reliance on the synthetic chemical pesticides that can damage environmental and human health. This study focused on interactions between a novel biocontrol‐strain, Bacillus sp. JC12GB43, and potato‐pathogenic Phytophthora and Fusarium species. In assays carried out in vitro and on the potato tuber, the bacterium was capable of near‐complete inhibition of pathogens. This Bacillus was sufficiently xerotolerant (water activity limit for growth = 0.928) to out‐perform Phytophthora infestans (~0.960) and challenge Fusarium coeruleum (~0.847) and Fusarium sambucinum (~0.860) towards the lower limits of their growth windows. Under some conditions, however, strain JC12GB43 stimulated proliferation of the pathogens: for instance, Fusarium coeruleum growth‐rate was increased under chaotropic conditions in vitro (132 mM urea) by >100% and on tubers (2‐M glycerol) by up to 570%. Culture‐based assays involving macromolecule‐stabilizing (kosmotropic) compatible solutes provided proof‐of‐principle that the Bacillus may provide kosmotropic metabolites to the plant pathogen under conditions that destabilize macromolecular systems of the fungal cell. Whilst unprecedented, this finding is consistent with earlier reports that fungi can utilize metabolites derived from bacterial cells. Unless the antimicrobial activities of candidate biocontrol strains are assayed over a full range of field‐relevant parameters, biocontrol agents may promote plant pathogen infections and thereby reduce crop yields. These findings indicate that biocontrol activity, therefore, ought to be regarded as a mode‐of‐behaviour (dependent on prevailing conditions) rather than an inherent property of a bacterial strain.