Disease Tolerance and Changes in Antioxidative Abilities in Mycorrhizal Strawberry Plants

Abstract

Tolerance to fusarium wilt and anthracnose and the changes in antioxidative abilities in mycorrhizal strawberry plants were investigated. Strawberry (Fragaria × ananassa Duch., ‘Nohime’) runner plants were inoculated with arbuscular mycorrhizal fungus (Glomus mosseae, AMF) and treated with a split root system. Ten weeks after AMF inoculation, Fusarium oxysporum f. sp. fragariae and Colletotrichum gloeosporioides were inoculated. Mycorrhizal plants accumulated a higher dry weight of shoots and roots than non-mycorrhizal plants 10 weeks after AMF inoculation. Four weeks after pathogen inoculation, disease incidence and severity of symptoms were eased in shoots and roots of mycorrhizal plants, especially with fusarium wilt; induced tolerance also appeared in split root-treated mycorrhizal plants. No major difference in antioxidative abilities took place before pathogen inoculation among plots; however, 4 weeks after pathogen inoculation, mycorrhizal plants showed higher values in the following items; SOD activity, DPPH radical scavenging activity, total polyphenol content, ascorbic acid content, effects differed with plant parts. From these findings, plant growth enhancement and tolerance to fusarium wilt, including induced tolerance, and anthracnose occurred in mycorrhizal strawberry plants. In this case, antioxidative abilities increased under pathogen-stressed conditions, so that disease tolerance might be associated with the increase in such antioxidative factors.