Components of different signalling pathways regulated by a new orthologue of AtPROPEP1 in tomato following infection by pathogens

Abstract

Plants express different defence mechanisms in response to pathogens. Understanding the recognition of pathogenassociated molecular patterns (PAMPs) by specific receptors, and the role of endogenous signals such as AtPep1 that regulate expression of genes in Arabidopsis thaliana, has aided the understanding of the defence mechanisms in different species. The aim of this study was to identify possible orthologous sequences of AtPROPEPs in tomato (Solanum lycopersicum) and characterize its role in resistance to necrotrophic pathogens. The presence of an orthologue of the A. thaliana AtPROPEP1 gene in S. lycopersicum, SlPROPEP, by in silico analysis, is reported here. This has 96% identity with the C-terminal region of a previously described potato peptide, another possible orthologue of AtPep1. A virus-induced gene silencing (VIGS) system was employed to investigate the role of the SlPROPEP. Silencing of SlPRO-PEP in tomato made plants more susceptible to Pythium dissotocum; approximately 30% of SlPROPEP-silenced plants showed stem constriction compared with 4% in control plants. Furthermore, quantification of P. dissotocum by qPCR revealed that the increase in symptom severity in SlPROPEP-silenced plants was associated with a 15 times increase in growth of the pathogen compared to control plants. Silencing of SlPROPEP also resulted in decreased expression of genes involved in plant defence against pathogens, such as PR-1, PR-5, ERF1, LOX-D and DEF2. These results suggest that SlPROPEP is involved in tomato resistance to P. dissotocum and probably acts as a pathogen-associated molecular pattern through signalling pathways mediated by jasmonic acid/ethylene (JA/ET).

Quantitative Peptidomics Study Reveals That a Wound-Induced Peptide from PR-1 Regulates Immune Signaling in Tomato

“…CAPE1 was shown to be a DAMP elicitor in this study as it was induced by wounding and activated defense responses. Although several peptides in tomato are proposed to be DAMPs, the evidence for a peptide DAMP is mainly based on the consideration of the precursor gene induced by the damage or the bioactivity of synthesized putative peptides (Pearce et al, 1991;Huffaker et al, 2006;Trivilin et al, 2014). Microarray and qRT-PCR analysis showed that CAPE1 can induce defense genes to produce immune responses against herbivores and pathogens.…”

“…It is expected that several signaling peptides are involved in combating herbivore and pathogen attack (Cheong et al, 2002;Francia et al, 2007;Chassot et al, 2008), but the details of the regulation of antiherbivore and antipathogen responses by peptides during wounding stress still await elucidation. Several DAMP peptides have been discovered in other plant species and suggested to be bioactive in tomato (Boller and Felix, 2009b;Campos et al, 2014); these include HypSys (Pearce et al, 2001a;Narvaez-Vasquez et al, 2007), RALF (Pearce et al, 2001b), and Pep1 (Huffaker et al, 2006;Trivilin et al, 2014). Pep1 was clearly identified to be pathogen related in Arabidopsis, and its putative precursor in tomato was recently found to involve in the antipathogen response (Trivilin et al, 2014).…”

“…Several DAMP peptides have been discovered in other plant species and suggested to be bioactive in tomato (Boller and Felix, 2009b;Campos et al, 2014); these include HypSys (Pearce et al, 2001a;Narvaez-Vasquez et al, 2007), RALF (Pearce et al, 2001b), and Pep1 (Huffaker et al, 2006;Trivilin et al, 2014). Pep1 was clearly identified to be pathogen related in Arabidopsis, and its putative precursor in tomato was recently found to involve in the antipathogen response (Trivilin et al, 2014). However, its endogenous level in tomato has not yet been proved to be induced by tissue damage or MeJA, a potent inducer of systemic wound signaling and response in tomato (Scheer and Ryan, 1999).…”

The Plant Peptidome: An Expanding Repertoire of Structural Features and Biological Functions

“…CAPE1 was significantly upregulated after wounding and/or methyl jasmonate treatment, similar to systemin (Chen et al, 2014). It is suggested that CAPE1 may be a novel DAMP (damage-associated molecular pattern) for induction of immunity, similar to HYPSYS, RALF, and At-Pep1 (Pearce et al, 2001a(Pearce et al, , 2001bHuffaker et al, 2006;Albert, 2013;Trivilin et al, 2014). Recently, it was shown that At-CAPE1 functions as a negative regulator of salt stress (Chien et al, 2015).…”

Plant elicitor peptides in induced defense against insects

“…Pretreatment of maize with ZmPep1 prior to infection reduces symptoms and cell death caused by the fungal pathogens Cochliobolus heterostrophus (Southern leaf blight) and Colletotrichum heterostrophus (Anthracnose stalk rot) [51]. Conversely, silencing of a tomato PROPEP gene results in plants that are less resistant to root rot by Pythium species than wild type [52].…”