Plant Pathogenic Fungi and Oomycetes

Fungi and Oomycetes are notorious plant pathogens and use similar strategies to infect plants. The majority of plants, however, is not infected by pathogens as they recognize pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors that mediate PAMP-triggered immunity (PTI) , a basal defense response effective against potential pathogens. Successful pathogens secrete effectors to suppress PTI and alter host plant physiology. In turn, plants have evolved immune receptors that recognize effectors, resulting in effector-triggered immunity (ETI) . ETI includes the hypersensitive response which is effective against biotrophic plant pathogens that require living cells to feed on. Other pathogens are hemi-biotrophic, which start infection as a biotroph, but after having colonized the host tissue can also feed on death tissue. Necrotrophic pathogens kill host tissue before they start to feed on it. Co-evolution between pathogens and their hosts had led to the development of numerous effectors produced by pathogens and corresponding resistance proteins in host plants, which has generated an arms race genetically described by the gene-for-gene concept. Resistance genes can now successfully be transferred to crop plants by classical breeding or as transgenes stapled into one cultivar.