Splivallo Richard, Deveau Aurélie, Valdez Nayuf, Kirchhoff Nina, Frey-Klett Pascale, Karlovsky Petr
Molecular Phytopathology and Mycotoxin Research, Georg-August University of Goettingen, Goettingen, Germany.
Institute for Molecular Biosciences, Biozentrum/Campus Riedberg, Frankfurt am Main, Germany.
Environ Microbiol. 2015 Aug;17(8):2647-60. doi: 10.1111/1462-2920.12521. Epub 2014 Jul 9.
Truffles, symbiotic fungi renown for the captivating aroma of their fruiting bodies, are colonized by a complex bacterial community of unknown function. We characterized the bacterial community of the white truffle Tuber borchii and tested the involvement of its microbiome in the production of sulphur-containing volatiles. We found that sulphur-containing volatiles such as thiophene derivatives, characteristic of T. borchii fruiting bodies, resulted from the biotransformation of non-volatile precursor(s) into volatile compounds by bacteria. The bacterial community of T. borchii was dominated by α- and β-Proteobacteria. Interestingly, all bacteria phyla/classes tested in this study were able to produce thiophene volatiles from T. borchii fruiting body extract, irrespective of their isolation source (truffle or other sources). This indicates that the ability to produce thiophene volatiles might be widespread among bacteria and possibly linked to primary metabolism. Treatment of fruiting bodies with antibacterial agents fully suppressed the production of thiophene volatiles while fungicides had no inhibitory effect. This suggests that during the sexual stage of truffles, thiophene volatiles are exclusively synthesized by bacteria and not by the truffle. At this stage, the origin of thiophenes precursor in T. borchii remains elusive and the involvement of yeasts or other bacteria cannot be excluded.
松露是一种共生真菌，以其子实体迷人的香气而闻名，它被一个功能未知的复杂细菌群落所定殖。我们对白松露（Tuber borchii）的细菌群落进行了表征，并测试了其微生物群在含硫挥发性化合物产生中的作用。我们发现，含硫挥发性化合物，如松露子实体特有的噻吩衍生物，是由细菌将非挥发性前体转化为挥发性化合物而产生的。白松露的细菌群落以α-和β-变形菌为主。有趣的是，本研究中测试的所有细菌门/纲都能够从白松露子实体提取物中产生噻吩挥发性化合物，无论其分离来源（松露或其他来源）如何。这表明产生噻吩挥发性化合物的能力可能在细菌中广泛存在，并且可能与初级代谢有关。用抗菌剂处理子实体完全抑制了噻吩挥发性化合物的产生，而杀菌剂则没有抑制作用。这表明在松露的有性阶段，噻吩挥发性化合物仅由细菌合成，而不是由松露合成。在这个阶段，白松露中噻吩前体的来源仍然难以捉摸，酵母或其他细菌的参与也不能排除。
