RESUMEN
Pungent traits caused by capsaicinoids are characteristic of chili peppers (Capsicum spp.), and the pungent-variable sweet chili pepper 'Shishito' (Capsicum annuum) is unique in being known for the pungency in fruits with few seeds. In the present study, we tried to clarify the relationship between the number of seeds and pungency in 'Shishito'. First, we investigated the pungency of 'Shishito' by simple sensory evaluations and quantifications of capsaicinoids by high-performance liquid chromatography. As a result, few-seeded fruits had a larger fluctuation of capsaicinoid content than many-seeded ones. This indicates that the number of seeds, in particular a decrease of the seeds, has some sort of connection with the pungency of 'Shishito'. Then, we analyzed the relationship between pungency and gene expression involving capsaicinoid biosynthesis at the individual fruit level. We vertically separated the placental septum in which capsaicinoids are synthesized and performed quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for 18 genes involved in capsaicinoid biosynthesis. We also used the placental septum for capsaicinoid quantification so that the gene expression levels and capsaicinoid contents in the same fruits were obtained, and their correlations were analyzed using 20 biological replicates. Among the 18 genes, expression levels of 11 genes (WRKY9, CaMYB31, AT3, BCAT, BCKDH, KAS I, KAS III, ACL, CaKR1, FAT, and pAMT) had a significant positive correlation with the capsaicinoid concentration, and they were considered to upregulate capsaicinoid biosynthesis. These results provide new insights regarding the environmental variation of the pungency traits in chili peppers and the relationship between pungency, the number of seeds, and gene expression involved in capsaicinoid biosynthesis.
Asunto(s)
Capsicum/genética , Regulación de la Expresión Génica de las Plantas/genética , Expresión Génica/genética , Genes de Plantas/genética , Semillas/genética , Frutas/genéticaRESUMEN
Although the physiological effects of peroxidovanadium(V) complexes (pVs) have been extensively investigated both in vitro and in vivo with regard to their pharmacological activity, such as insulin-mimetic and antitumor activities, the relationship between the chemical and pharmacological properties of pVs is still unclear. Rational drug design with pVs depends on a full understanding of this relationship. Toward this end, the current report evaluates the physiological effects of 13 pVs were evaluated bound to a variety of ligand. Six of these ligands are tripodal tetradentate ligands, one is a linear tetradentate ligand, one boasts two pendant groups, three are tridentate ligands, and two are alkoxido-bridging, dinucleating ligands. The cytotoxicities of these pVs could be classified into three groups: significantly toxic, moderately toxic, and non- or negligibly toxic. Further, IC50 values could be related with the LMCT transition energies of the peroxido group, particularly among complexes with similar ligands. This relation indicates that the electronic properties of the peroxido group affected the physiological activity of the pV complex. We also investigated the insulin-signaling intensity of each pV. Phosphorylation of protein kinase B and extracellular signal-regulated kinase 1/2, two major insulin-signaling proteins, was observed after treating cells with pV for 30 min. Phosphorylation was particularly remarkable for complexes that exhibited high cytotoxicity. The present results demonstrate that the toxicity and physiological effects of pVs can be controlled by selecting an appropriate ancillary ligand. These findings provide a guide for synthesis of new pVs that may be used as candidate therapeutic agents.