Use of AMF to improve plant health
Strawberry wilt, caused by Verticillium dahliae Kleb., can reduce yield by up to 75%. For c. 40 years, soil was routinely fumigated with methyl bromide until it was banned by the 1994 Montreal Protocol which became effective in the UK in 2006. Another fumigant, chloropicrin, is to be withdrawn from Europe in the near future. Extensive effort has gone into finding alternatives. Among these, incorporation of green manures that release volatile fungitoxic compounds, so-called biofumigation, shows promise as a component of a disease management strategy.
Arbuscular mycorrhizal fungi (AMF) are ubiquitous in terrestrial ecosystems where they are major components of the soil microbial biomass. Mycorrhizal associations are multi-functional, assisting the plants in nutrient acquisition, water uptake, and protecting roots from pathogens. AMF have been shown to increase plant tolerance to V. dahliae on several crops, including pepper, strawberry and cotton. However, the beneficial effects offered by AMF can vary considerably. A recent publication showed that one particular AMF strain significantly reduced strawberry wilt when plants were inoculated at planting. Ensuring sufficient colonisation of strawberry planting materials (runners or tray plants) before trans-planting may further increase the benefit of AMF-symbiosis.
We are investigating whether AMF pre-colonised strawberry planting materials would reduce incidence or severity of wilt, focusing on the interaction among strawberry cultivars, AMF strains (species), and Verticillium strains with differing degrees of aggressiveness. Transcriptomic and histological studies will be conducted to investigate the likely genetic and physiological bases for the wilt suppressive effects offered by AMF. Finally it will investigate whether wilt can be further reduced when AMF is integrated with lavender waste derived products.