Quantification of Trichoderma afroharzianum, Trichoderma harzianum and Trichoderma gamsii inoculants in soil, the wheat rhizosphere and in planta suppression of the crown rot pathogen Fusarium pseudograminearum

作者：Belinda E. Stummer, Qian Zhang, Xinjian Zhang, Richard Warren, Paul R. Harvey · 发表于：Journal of Applied Microbiology · 年份：2020 · DOI：10.1111/jam.14670 · 被引用次数：36 · 研究领域：Plant-Microbe Interactions and Immunity、Mycotoxins in Agriculture and Food、Mycorrhizal Fungi and Plant Interactions

Develop quantitative assays (qPCR) to determine the detection threshold limits, colonization and persistence of Trichoderma gamsii, Trichoderma afroharzianum and T. harzianum inoculants in cropping soils, the wheat rhizosphere and their in planta suppressive efficacy against the crown rot pathogen Fusarium pseudograminearum. Trichoderma qPCR primers were designed from the internal transcribed spacer region of 5.8S rDNA and from sequences of DNA fragments diagnostic for each inoculant genotype. The minimum detection thresholds of qPCR assays varied between 1 × 103 (log 3) and 8 × 104 (log 4·9) conidia (genome) equivalents per gram of soil for multi‐ and single‐copy target sequences, respectively and were independent of soil type. There was a strong correlation (r > 0·974) between culture‐dependent and culture‐independent (qPCR) quantification methods. In wheat bioassays, Trichoderma inoculants colonized rhizosphere soils and wheat roots at 56–112 days postemergence to a depth of 20 cm but were more abundant (P < 0·001) at 0–10 cm root depth, means ranging from 2 × 102 (log 2·3) to 4 × 105 (log 5·6) conidia equivalents per gram of rhizosphere soil or root tissue. Inoculants reduced (P < 0·001) F. pseudograminearum biomass in wheat crown and root tissue by up to 5754‐fold and increased (P = 0·008) plant biomass, relative to the pathogen control. The qPCR assays provided sensitive and accurate assessment of wheat root and rhizosphere soil colonization of Trichoderma inoculants. S...