A Dynamic Interface for Capsaicinoid Systems Biology      

Abstract

(M.M.J.) Capsaicinoids are the pungent alkaloids that give hot peppers (Capsicum spp.) their spiciness. While capsaicinoids are relatively simple molecules, much is unknown about their biosynthesis, which spans diverse metabolisms of essential amino acids, phenylpropanoids, benzenoids, and fatty acids. Pepper is not a model organism, but it has access to the resources developed in model plants through comparative approaches. To aid research in this system, we have implemented a comprehensive model of capsaicinoid biosynthesis and made it publicly available within the SolCyc database at the SOL Genomics Network (http://www.sgn.cornell.edu). As a preliminary test of this model, and to build its value as a resource, targeted transcripts were cloned as candidates for nearly all of the structural genes for capsaicinoid biosynthesis. In support of the role of these transcripts in capsaicinoid biosynthesis beyond correct spatial and temporal expression, their predicted subcellular localizations were compared against the biosynthetic model and experimentally determined compartmentalization in Arabidopsis (Arabidopsis thaliana). To enable their use in a positional candidate gene approach in the Solanaceae, these genes were genetically mapped in pepper. These data were integrated into the SOL Genomics Network, a clade-oriented database that incorporates community annotation of genes, enzymes, phenotypes, mutants, and genomic loci. Here, we describe the creation and integration of these resources as a holistic and dynamic model of the characteristic specialized metabolism of pepper.

Genome sequence of the hot pepper provides insights into the evolution of pungency in Capsicum species

“…3a). Although the biosynthetic genes have been npg partly elucidated [33][34][35] , the biochemical reactions, evolution and regulation of capsaicinoid biosynthesis are still largely unknown. Using homology, microsynteny and previous reports 35 , we identified all orthologous genes of the capsaicinoid pathway in the tomato genome (Supplementary Fig.…”

A <i>Comt</i>1 Loss of Function Mutation Is Insufficient for Loss of Pungency in <i>Capsicum</i>

“…Participation of COMT in phenylpropanoid-mediated capsaicinoid biosynthesis has long been proposed [5] [7] [18] [19]. Mozourek et al [9] proposed the participation of caffeoyl-CoA O-methyltransferase (CCoAOMT) instead of COMT in the phenylpropanoid pathway of capsaicinoid biosynthesis. Thus, further study is needed to clarify which genes are critically important for capsaicinoid biosynthesis and could be a target for controlling fruit pungency in Capsicum.…”

“…The general capsaicinoid biosynthetic pathway has been studied for almost half a century, and transcripts expressed in placenta tissue of pungent cultivars have been isolated [7]- [9].…”

Yield, Capsaicin Content and Peroxidase Enzyme Activity of Four Chili Cultivars on Three Environments

“…Peroxidase activity increased when capsaisinoid concentration decreased. Measurement of the enzyme activity could be an important indication for capsaisinoid metabolism regulation (Diaz et al, 2004;Mazourek et al, 2009;Gonzalez et al, 2011 ). Peroxidase does not only play a role in plant defense against bio-tropic and necro-tropic pathogens, but also acts as a biomarker of biotic and abiotic stresses, for example to drought stress.…”

“…In most species of Capsicum, accumulation of capsaicin in the fruit begins about 20 days post-anthesis (DPA). Capsaicin biosynthesis occurs in the epidermal cells of the placenta, where they subsequently secreted towards the outer wall of the cell, and eventually accumulated in the structure called blister located on the surface of the placenta (Mazourek et al, 2009). …”