Dipartimento di Scienze Biomolecolari, University of Urbino Carlo Bo, Urbino, Italy.
Fungal Biol. 2010 Nov-Dec;114(11-12):936-42. doi: 10.1016/j.funbio.2010.09.001. Epub 2010 Sep 15.
Diversity of nitrogen-fixing bacteria and the nitrogen-fixation activity was investigated in Tuber magnatum, the most well-known prized species of Italian white truffle. Degenerate PCR primers were applied to amplify the nitrogenase gene nifH from T. magnatum ascomata at different stages of maturation. Putative amino acid sequences revealed mainly the presence of Alphaproteobacteria belonging to Bradyrhizobium spp. and expression of nifH genes from Bradyrhizobia was detected. The nitrogenase activity evaluated by acetylene reduction assay was 0.5-7.5μmolC(2)H(4)h(-1)g(-1), comparable with early nodules of legumes associated with specific nitrogen-fixing bacteria. This is the first demonstration of nitrogenase expression gene and activity within truffle.
本研究调查了意大利白松露中最著名的块菌品种——块菌中固氮菌的多样性及其固氮活性。采用简并 PCR 引物从不同成熟阶段的块菌子实体中扩增固氮酶基因 nifH。推测的氨基酸序列主要表明存在属于慢生根瘤菌属的α-变形菌，并且检测到了慢生根瘤菌的 nifH 基因表达。乙炔还原测定法评估的固氮酶活性为 0.5-7.5μmolC(2)H(4)h(-1)g(-1)，与具有特定固氮菌的豆科植物早期根瘤相当。这是首次在块菌中证明固氮酶表达基因和活性的存在。
