Background: The world needs a sustainable and secure supply of fresh and affordable food. Increased demand for berries is being driven by their popularity and consumer belief in their healthful properties. Like many crop and tree species, strawberries and raspberries are susceptible to oomycete diseases. Phytophthora root rot (PRR) has reduced in-soil raspberry production by 80 % in the UK. Phytophthora rubi and P. fragariae spread rapidly through trade in plant propagules, contaminated soil and irrigation water. Chemical control methods are limited although some resistant cultivars are now available commercially. There is an urgent need to find durable and sustainable methods to produce raspberry.
Some beneficial microbes e.g. arbuscular mycorrhizal (AM) fungi are obligate biotrophs that form endosymbiosis with most plants. AM fungi grow mycelium that enter roots establishing branched hyphal feeding structures (arbuscules) and extraradically in the soil for mineral nutrient uptake and spore formation. Both oomycetes and AM fungi, share a requirement to find an appropriate host, penetrate living root tissue, develop hyphae in the apoplast and insert transient feeding structures into living host cells.
Aims/Objectives: One of the top 10 questions in plant microbe interactions is ‘how do plants engage with beneficial microorganisms while restricting pathogens?’ and here we will be examining whether AM fungi can provide soft fruit crops protection to Phytophthoras.
Methods/Approach: Firstly, a screen of soft fruit interacting AM fungi will be performed to see interaction with a range of root rot resistant and susceptible cultivars of raspberry and strawberry could be detected. The student will learn to use WinRhizo software to examine root architecture and identify characteristics that make hosts more-or-less amenable to particular microbe interactions. Positive/negative effects of AM fungi presence/interaction on the host of pathogenic oomycetes will be examined. Transgenic Phytophthora expressing fluorescent tags will be used to track disease progression in roots. Disease assays in potted plants and examining data from commercial trials will be developed. The student will examine whether a pathogen and an AM fungi can coexist in the same host, are they mutually exclusive or perhaps competing for host resources? Samples will be collected from hosts challenged with oomycetes, AM fungi and in combination to perform RNAseq then examine the potential effect of AM fungi on the host immunity?
12-18month outline plan: The student will learn about both beneficial fungi, pathogenic oomycetes, plant immunity and root architecture. They will learn basic molecular plant pathology techniques involved in the generation of root material and setting up infections. They will learn how to stain the root to examine the cell types and for immunity responses in the root and learn to propagate and inoculate roots with the AMF fungi. The data generated by this proposal will not only provide publishable advances in the field of molecular plant pathology that the student will help us write and generate the figures. The student will also provide commercially relevant information about novel and sustainable crop protection methods.
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