|Title||Phytophthora blight in potato: tipping the balance between resistance and susceptibility|
|Author(s)||Govers, F.; Wang, Y.; Du, Y.; Yang, Shuqing; Bouwmeester, K.|
|Event||13th Solanaceae Conference, Davis, California , 2016-09-12/2016-09-16|
Laboratory of Phytopathology
|Publication type||Abstract in scientific journal or proceedings|
|Abstract||Plants are continuously challenged by pathogens but because of their effective multi-layered defence system plant diseases are an exception rather than a rule. The first layer of defence is governed by plasma membrane-associated receptors known as pattern recognition receptors (PPRs). The second layer is mediated by intracellular receptors, which are largely nucleotide-binding leucine-rich repeat (NLR) proteins also known as resistance (R) proteins. Our research focuses on late blight, a devastating disease on potato and tomato that is caused by the oomycete pathogen Phytophthora infestans, and infamous because of the Irish potato famine in the mid 19th century. To colonize host plants, pathogens secrete effectors that can modulate host defence. Well-known are the RXLR effectors that are produced by Phytophthora species and related oomycetes, and translocated into host cells. To counteract the pathogen, potato exploits R proteins, the intracellular NLR immune receptors that confer
resistance to P. infestans upon recognition of a RXLR effector, with each R protein having its own matching RXLR effector (or AVR protein). In the absence of a matching R protein, RXLR effectors manipulate the cell machinery by targeting host proteins, the so-called effector targets, thereby paving
the way for successful infection. As an example I will elaborate on the NLR R1 in potato, its matching effector AVR1 in P. infestans, and the AVR1 effector target Sec5, a subunit of the exocyst complex. In addition to R proteins there are also some PRRs known that confer resistance to Phytophthora. We identified a family of cell surface receptors classified as L-type lectin receptor kinases (LecRKs).
Arabidopsis has 45 LecRK genes, of which several play a role in resistance to a variety of plant pathogens including Phytophthora. LecRKs are wide-spread in plants, and this justifies exploitation of LecRKs as novel sources for disease resistance. A further understanding of the mechanisms underlying R protein- and PPR-mediated resistance is crucial to design novel strategies for introducing resistance traits in crops.