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The cuticle constitutes the outermost defensive barrier of most land plants. It comprises a polymeric matrix-cutin, surrounded by soluble waxes. Moreover, the cuticle constitutes the first line of defense against pathogen invasion, while also protecting the plant from many abiotic stresses. Aliphatic monomers in cutin have been suggested to act as immune elicitors in plants. This study analyses the potential of cutin oligomers to activate rapid signaling outputs reminiscent of pattern-triggered immunity in the model plant Arabidopsis. Cutin oligomeric mixtures led to Ca2+ influx and mitogen-activated protein kinase activation. Comparable responses were measured for cutin, which was also able to induce a reactive oxygen species burst. Furthermore, cutin oligomer treatment resulted in a unique transcriptional reprogramming profile, having many archetypal features of pattern-triggered immunity. Targeted spectroscopic and spectrometric analyses of the cutin oligomers suggest that the elicitor compounds consist mostly of two up to three 10,16-dihydroxyhexadecanoic acid monomers linked together through ester bonds. This study demonstrates that cutin breakdown products can act as inducers of early plant immune responses. Further investigation is needed to understand how cutin breakdowns are perceived and to explore their potential use in agriculture.

Abstract Background Oocytes of large animal species isolated from small ovarian follicles (

Fresh horticultural products are economically significant foods that are highly demanded by consumers worldwide; however, they are highly perishable and susceptible to deterioration by fungi, which contribute to their short shelf-life and cause significant post-harvest losses. Among the alternatives suggested for fungal control in plants is the elicitation of the innate plant defense mechanism, which may be activated when specific molecules of the phytopathogen, such as chitin, are recognized. Chitin is a long-chain polymer of N-acetyl-α-D-glucosamine of the fungal cell wall; it possesses biological activity by eliciting the plant immune response. This molecule and its oligosaccharides are recognized through transmembrane receptors known as receptor-like kinases (RLKs) and receptor-like proteins (RLPs). Mediated by receptor-like cytoplasmic kinases (RLCKs), which bind to the intracellular domain of these receptors, they initiate intracellular signal transduction via MAP kinases, triggering the plant defense response. In model plants, such as Oryza sativa (rice) and Arabidopsis thaliana, the set of RLK/RLP-RLCK-MAP kinases is involved in plant immunity triggered by chitin. Furthermore, in horticultural products, research into the molecular events between these three elements has suggested that similar processes occur. However, little is known about these molecular events in fruits. Against this background, the present review provides the most recent and relevant findings on the molecular associations of these three elements in the response to fungal chitin in plants and outlines which elements could participate in this signaling process in horticultural crops. [ABSTRACT FROM AUTHOR]

Fresh horticultural products are economically significant foods that are highly demanded by consumers worldwide; however, they are highly perishable and susceptible to deterioration by fungi, which contribute to their short shelf-life and cause significant post-harvest losses. Among the alternatives suggested for fungal control in plants is the elicitation of the innate plant defense mechanism, which may be activated when specific molecules of the phytopathogen, such as chitin, are recognized. Chitin is a long-chain polymer of N-acetyl-α-D-glucosamine of the fungal cell wall; it possesses biological activity by eliciting the plant immune response. This molecule and its oligosaccharides are recognized through transmembrane receptors known as receptor-like kinases (RLKs) and receptor-like proteins (RLPs). Mediated by receptor-like cytoplasmic kinases (RLCKs), which bind to the intracellular domain of these receptors, they initiate intracellular signal transduction via MAP kinases, triggering the plant defense response. In model plants, such as Oryza sativa (rice) and Arabidopsis thaliana, the set of RLK/RLP-RLCK-MAP kinases is involved in plant immunity triggered by chitin. Furthermore, in horticultural products, research into the molecular events between these three elements has suggested that similar processes occur. However, little is known about these molecular events in fruits. Against this background, the present review provides the most recent and relevant findings on the molecular associations of these three elements in the response to fungal chitin in plants and outlines which elements could participate in this signaling process in horticultural crops.

We recently reported an RAF rearrangement without NRAS or BRAF mutations in lesions from Giant Congenital Melanocytic Nevi (CMN). The new gene fusion involves the 5′‐end of the promoter‐containing N terminus of the SOX5 gene fused to exons 7–16 of the 3′‐end of RAF1 gene leading to a SOX5‐RAF1 fusion transcript which loses the auto‐inhibitory CR1 domain but retains the complete in‐frame coding sequence for the C‐Terminal kinase domain of the RAF1. Stable expression of SOX5‐RAF1 fusion induced growth factor‐independent cell growth in murine hematopoietic Ba/F3 cells and melan‐a immortalized melanocytes. Besides, it led to the transformation of both Ba/F3 and NIH 3T3 cells as revealed by colony formation assays. Furthermore, its expression results in MAPK activation assessed by increased levels of p‐ERK protein in the cytosol of transduced cells. Treatment with Sorafenib and UO126 inhibited proliferation of Ba/F3‐SOX5‐RAF1 cells in the absence of IL3 but not the PLX 4720, a specific inhibitor of BRAF. Moreover, the tumorigenic and metastatic capacities of SOX5‐RAF1 were assessed in vivo. These results indicate that SOX5‐RAF1, a driver event for CMN development, has oncogenic capacity. Thus, sequencing of CMN transcriptomes may lead to the identification of this druggable fusion and interfere with the progression toward melanoma. [ABSTRACT FROM AUTHOR]