科研之友
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摘要
Phialocephala scopiformis Kowalski & Kehr is a foliar fungal endophyte of white spruce (Picea glauca (Moench) Voss) that produces the anti-insect compound rugulosin and other compounds in lower amounts. Seedlings inoculated with this and other toxigenic endophytes have increased tolerance to the spruce budworm Choristoneura fumiferana (Clemens, 1865). The presence of rugulosin in the diet and in needles infected by P. scopiformis reduces the growth rate of the insect. One of 300 white spruce trees inoculated as a seedling in 2001 was chosen to investigate the distribution of P. scopiformis and its principal toxin rugulosin throughout the crown. To facilitate the detection of the fungus in small samples, a qPCR assay was developed based on the ITS region of fungal ribosomal DNA targeting a genetic polymorphism unique to P. scopiformis. The assay was specific, with a method limit of detection 100 ng mycelium per gram needle sample with high reproducibility and accuracy. We found that 11 years after inoculation, P. scopiformis DAOM 229536 and its toxin were detectable in needle samples distributed throughout the crown. Of the 109 samples tested, 100% of the rugulosin-positive samples also tested positive for P. scopiformis DAOM 229536 DNA in the qPCR assay. The mean and median needle rugulosin concentrations were >2 times that required to reduce the growth of spruce budworm.
- 出版日期2014-9
