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Influence of O 2 and CO 2 on fungal development and hydrophobin expression during the interaction between Heterobasidion parviporum and Phlebiopsis gigantea
Author(s) -
Kern Linda,
Linkies Ada
Publication year - 2019
Publication title -
forest pathology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.535
H-Index - 49
eISSN - 1439-0329
pISSN - 1437-4781
DOI - 10.1111/efp.12511
Subject(s) - gigantea , heterobasidion annosum , biology , hydrophobin , conidium , germination , botany , spore , horticulture , gene , biochemistry , picea abies
Abstract Heterobasidion annosum is a very destructive fungal pathogen causing massive losses on forest trees in the northern hemisphere. Tree infection usually takes place through the cut surface after felling. Phlebiopsis gigantea is commonly used as a biological control agent, applied directly after cutting on the stump surface. We investigated the interaction between both fungi in different gas compositions with lowered O 2 (0.1% and 0.4%) and enhanced CO 2 (15%) concentrations, imitating conditions as present on the wood surface and inside living wood tissue. When grown under 0.1% O 2 and 15% CO 2 , fungal development of both species was altered, growth rate of P. gigantea was decreased and of H. parviporum slightly increased. Low O 2 and high CO 2 induced the formation of highly hydrophilic tissue with impaired conidia formation and germination capacity. In H. parviporum, this effect was more striking after 7 dpi with 45% reduced vitality, in P. gigantea after 14 dpi with 89% vitality reduction. These observations suggest that entering the tree through the cut surface is accompanied by altering fungal tissue to be more hydrophilic with a concurrent reduction of conidia formation and germination. Expression of the hydrophobin genes HAH1 and HAH2 of H. parviporum at ambient air decreased significantly in response to fungal interaction with P. gigantea . Gene expression was also influenced by O 2 and CO 2 content. Reduction of O 2 to 0.4% led to significantly decreased transcription rate of both HAH1 and HAH2 in single and dual cultures.