Phytophthora infestans small phospholipase D‐like proteins elicit plant cell death and promote virulence

Abstract

The successful invasion of host tissue by (hemi-)biotrophic plant pathogens is dependent on modifications of the host plasma membrane to facilitate the two-way transfer of proteins and other compounds. Haustorium formation and the establishment of extrahaustorial membranes are probably dependent on a variety of enzymes that modify membranes in a coordinated fashion. Phospholipases, enzymes that hydrolyse phospholipids, have been implicated as virulence factors in several pathogens. The oomycete Phytophthora infestans is a hemibiotrophic pathogen that causes potato late blight. It possesses different classes of phospholipase D (PLD) proteins, including small PLD-like proteins with and without signal peptide (sPLD-likes and PLD-likes, respectively). Here, we studied the role of sPLD-like-1, sPLD-like-12 and PLD-like-1 in the infection process. They are expressed in expanding lesions on potato leaves and during in vitro growth, with the highest transcript levels in germinating cysts. When expressed in planta in the presence of the silencing suppressor P19, all three elicited a local cell death response that was visible at the microscopic level as autofluorescence and strongly boosted in the presence of calcium. Moreover, inoculation of leaves expressing the small PLD-like genes resulted in increased lesion growth and greater numbers of sporangia, but this was abolished when mutated PLD-like genes were expressed with non-functional PLD catalytic motifs. These results show that the three small PLD-likes are catalytically active and suggest that their enzymatic activity is required for the promotion of virulence, possibly by executing membrane modifications to support the growth of P. infestans in the host.

Expression and functional analysis of a PR-1 Gene,MuPR1, involved in disease resistance response in mulberry (Morus multicaulis)

“…Moreover, the tomato preproprotein PR1b was characterized by containing the PxGNxxxxxPY motif in the C-terminus. The CAP-derived peptide 1-like (CAPE1-like) of the C-terminal portion was discovered to have functions in induced immunity in the defense signaling as a novel damage-associated molecular pattern (Chen et al 2014;Chien et al 2015;Meijer et al 2019). Therefore, the exact biological function and bioactivity pathway of PR-1 proteins need to be further revealed, and in mulberry there is still little information related to PR1 genes.…”

Peptide Extracts from Seven Medicinal Plants Discovered to Inhibit Oomycete Phytophthora infestans, a Causative Agent of Potato Late Blight Disease

“…Taking another view, P. infestans is known to infect plant hosts that can realize protein virulence factors and that are activated in contact with a plant surface. These factors are enzymes (cyclophilins, phospholipases, and cutinases) [ 50 , 51 , 52 ], certain extracellular proteins that are represented by serine- and metalloproteinases [ 53 ], and a widely represented class of infection-associated effector proteins (with an N -terminal RXLR motif) [ 54 , 55 ].…”

Two Phytophthora parasitica cysteine protease genes, PpCys44 and PpCys45, trigger cell death in various Nicotiana spp. and act as virulence factors

“…Proteolysis of plant substrates is a strategy employed by pathogens to alter plant physiology (Hotson and Mudgett, ). Many enzyme effectors secreted by pathogens have been shown to manipulate plant immunity, such as the glycoside hydrolase 12 protein XEG1 (Ma et al , , ) from Phytophthora sojae ; small phospholipase D‐like proteins (Meijer et al , ) and serine proteases (Paris and Lamattina, ) from Phytophthora infestans ; and metalloproteases, subtilisin, aspartic proteases, aspartyl acid proteases, non‐aspartyl acid proteases, and cysteine proteases from plant pathogenic fungi (Chandrasekaran et al , ) and bacteria (Hotson and Mudgett, ; Potempa and Pike, ; Niño et al , ).…”