The pepper patatin-like phospholipase CaPLP1 functions in plant cell death and defense signaling

Abstract

Phospholipases hydrolyze phospholipids into fatty acids and other lipophilic substances. Phospholipid signaling is crucial for diverse cellular processes in plants. However, the precise role of phospholipases in plant cell death and defense signaling is not fully understood. Here, we identified a pepper (Capsicum annuum) patatin-like phospholipase (CaPLP1) gene that is transcriptionally induced in pepper leaves by avirulent Xanthomonas campestris pv. vesicatoria (Xcv) infection. CaPLP1 containing an N-terminal signal peptide localized to the cytoplasm and plasma membrane, leading to the secretion into the apoplastic regions. Silencing of CaPLP1 in pepper conferred enhanced susceptibility to Xcv infection. Defense responses to Xcv, including the generation of reactive oxygen species (ROS), hypersensitive cell death and the expression of the salicylic acid (SA)-dependent marker gene CaPR1, were compromised in the CaPLP1-silenced pepper plants. Transient expression of CaPLP1 in pepper leaves induced the accumulation of fluorescent phenolics, expression of the defense marker genes CaPR1 and CaSAR82A, and generation of ROS, ultimately leading to the hypersensitive cell death response. Overexpression (OX) of CaPLP1 in Arabidopsis also conferred enhanced resistance to Pseudomonas syringae pv. tomato (Pst) and Hyaloperonospora arabidopsidis infection. CaPLP1-OX leaves showed reduced Pst growth, enhanced ROS burst and electrolyte leakage, induction of the defense response genes AtPR1, AtRbohD and AtGST, as well as constitutive activation of both the SA-dependent gene AtPR1 and the JA-dependent gene AtPDF1.2. Together, these results suggest that CaPLP1 is involved in plant defense and cell death signaling in response to microbial pathogens.

NLR surveillance of essential SEC-9 SNARE proteins induces programmed cell death upon allorecognition in filamentous fungi

“…The finding that the N-terminal domain of PLP-1 has enzymatic activity essential for HI constitutes a unique role of NLRs, as other characterized N-terminal domains of animal and plant NLRs act as adaptors that perform signaling functions (36). Interestingly, patatin-like domains have been reported to play a role in host-defense-related PCD in plants (37,38). PLP-1-induced cell death could be a direct consequence of alteration of membrane phospholipids via the patatin-like phospholipase domain.…”

A novel zinc‐binding alcohol dehydrogenase 2 from Arachis diogoi, expressed in resistance responses against late leaf spot pathogen, induces cell death when transexpressed in tobacco

“…Differentially expressed TDF of Zinc binding alcohol dehydrogenase 2 also observed the upregulation of PAT3 gene; transient expression of a patatin like phospholipase in tobacco resulted in the accumulation of fluorescent phenolics, pathogenesis-related proteins CaPR1, CaSAR82A, and ROS leading to cell death in pepper leaves [35]. Expression profiling postfungal treatment in Populus trichocarpa showed possible involvement of CAD/CAD-like genes in plant development and defense against various pests and pathogens [36].…”

Overlapping Podospora anserina Transcriptional Responses to Bacterial and Fungal Non Self Indicate a Multilayered Innate Immune Response

“…In P. anserina NLR proteins, 7 N-terminal domains with a known annotation were identified, three of which (HET, HeLo, HeLo-like) known or suspected to induce cell death in P. anserina (Paoletti and Clavé, 2007 ; Daskalov et al, 2012 , 2015 ). Two N terminal domains are related to lipase, one (sesB) altering growth in Nectria haematococca (Graziani et al, 2004 ), the other (Patatin) controlling PCD and defense in plants (Kumar and Kirti, 2012 ; Kim et al, 2014 ). All these domains are also found in non-NLR proteins (Daskalov et al, 2012 ).…”