Virus-Induced Gene Silencing (VIGS) in Chili Pepper (Capsicum spp.).

Virus-induced gene silencing (VIGS) is a transcript suppression technique that enables the functional characterization of genes in recalcitrant transformation plants. This technique consists in cloning a short fragment of a gene of interest into a viral vector, such as TRV (Tobacco rattle virus), and this viral construction is used to agro-infiltrate the plant. VIGS induces posttranscriptional gene silencing (PTGS) that results in the specific sequence degradation of target RNAs. Here we describe a VIGS protocol using the Gateway-based TRV vector for the study of genes in chili pepper plants.

Biochemistry and molecular biology of capsaicinoid biosynthesis: recent advances and perspectives.

The most widely known characteristic of chili pepper fruits is their capacity to produce capsaicinoids, which are responsible for the pungent sensation. The capsaicinoids have several uses in different areas, such as the pharmaceutical, cosmetic and agronomic industries, among others. They are synthesized by the condensation of vanillylamine (derived from phenylalanine) with a branched-chain fatty acid (from valine or leucine precursors), and they generally accumulate in the placental tissue of the chili pepper fruits. The pungency grade depends on the genotype of the plant but is also affected by external stimuli. In recent years, new structural and regulatory genes have been hypothesized to participate in the capsaicinoid biosynthetic pathway. Moreover, the role of some of these genes has been investigated. Substantial progress has been made in discerning the molecular biology of this pathway; however, many questions remain unsolved. We previously reviewed some aspects of the biochemistry and molecular biology of capsaicinoid biosynthesis (Aza-González et al. Plant Cell Rep 30:695-706. Aza-González et al., Plant Cell Rep 30:695-706, 2011), and in this review, we describe advances made by different researchers since our previous review, including the contribution of omics to the knowledge of this pathway.