Phytophthora pluvialis maintenance, spore production and detached needle assays.

Phytophthora pluvialis is an oomycete that primarily infects Pinus radiata and Pseudotsuga menziesii causing the destructive foliar disease red needle cast (RNC). Recent observations show that P. pluvialis can also infect western hemlock inducing resinous cankers. High-throughput and reproducible infection assays are integral to find key information on tree health and oomycete pathogenicity. In this protocol, we describe the propagation and spore induction of P. pluvialis, followed by detached needle assays for verification and quantification of virulence of P. pluvialis in P. radiata needles. These needle assays can be employed for high-throughput screening of tree needles with diverse genetic backgrounds. In downstream analysis, Quantitative PCR (qPCR) was utilized to assess relative gene expression, as exemplified by candidate RxLR effector protein PpR01. Additional techniques like RNA sequencing, metabolomics, and proteomics can be combined with needle assays and can offer comprehensive insights into P. pluvialis infection mechanisms.

Interior design: how plant pathogens optimize their living conditions.

Pathogens use effectors to suppress host defence mechanisms, promote the derivation of nutrients, and facilitate infection within the host plant. Much is now known about effectors that target biotic pathways, particularly those that interfere with plant innate immunity. By contrast, an understanding of how effectors manipulate nonimmunity pathways is only beginning to emerge. Here, we focus on exciting new insights into effectors that target abiotic stress adaptation pathways, tampering with key functions within the plant to promote colonization. We critically assess the role of various signalling agents in linking different pathways upon perturbation by pathogen effectors. Additionally, this review provides a summary of currently known bacterial, fungal, and oomycete pathogen effectors that induce biotic and abiotic stress responses in the plant, as a first step towards establishing a comprehensive picture for linking effector targets to pathogenic lifestyles.