Effects of AM fungi and grass endophytes on perennial ryegrass Bipolaris sorokiniana leaf spot disease under limited soil nutrients
2019
Guo, Yane | Gao, Ping | Li, Fang | Duan, Tingyu
Both arbuscular mycorrhizal fungi (AMF) Claroideoglomus etunicatum and grass endophytes (Epichloë) could improve disease tolerance. Research is limited on the dual infection by AMF and Epichloë on plant diseases. Bipolaris sorokiniana is a fungal species that causes leaf spot in cereals, and also in perennial ryegrass (Lolium perenne), impacting its growth and production. This experiment tested the dual infection of AMF and Epichloë on perennial ryegrass growth and the physiological and biochemical indexes under limited soil conditions occurs in nature ecosystem. The results showed that infection with B. sorokiniana significantly decreased plant growth and shoot N concentration (P < 0.05), and this negative effect was exaggerated by AMF × Epichloë. The pathogen alone decreased AMF colonization (P < 0.05); however, the interactions of the pathogen and grass endophyte showed the highest value of perennial ryegrass AM colonization. Infection with AMF or Epichloë alone, or the combination of the two, suppressed the occurrence of leaf spot. Epichloë×AMF × B. sorokiniana had the highest amount of β-1,3-glucanase activity and jasmonic acid activity, whereas AMF and Epichloë alone or combined significantly increased the lignin content in diseased plants (P < 0.05). Limited soil nutrients did not affect the inhibition function of AMF and Epichloë for PRG leaf spot disease.
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