Transcriptomic analyses of cacao cell suspensions in light and dark provide target genes for controlled flavonoid production.

Catechins, including catechin (C) and epicatechin (E), are the main type of flavonoids in cacao seeds. They play important roles in plant defense and have been associated with human health benefits. Although flavonoid biosynthesis has been extensively studied using in vitro and in vivo models, the regulatory mechanisms controlling their accumulation under light/dark conditions remain poorly understood. To identify differences in flavonoid biosynthesis (particularly catechins) under different light treatments, we used cacao cell suspensions exposed to white-blue light and darkness during 14 days. RNA-Seq was applied to evaluate differential gene expression. Our results indicate that light can effectively regulate flavonoid profiles, inducing a faster accumulation of phenolic compounds and shifting E/C ratios, in particular as a response to switching from white to blue light. The results demonstrated that HY5, MYB12, ANR and LAR were differentially regulated under light/dark conditions and could be targeted by overexpression aiming to improve catechin synthesis in cell cultures. In conclusion, our RNA-Seq analysis of cacao cells cultured under different light conditions provides a platform to dissect key aspects into the genetic regulatory network of flavonoids. These light-responsive candidate genes can be used further to modulate the flavonoid production in in vitro systems with value-added characteristics.

Effects of (-)-epicatechin on frontal cortex DAPC and dysbindin of the mdx mice.

INTRODUCTION: Multiple components of the dystrophin-associated protein complex (DAPC) are expressed in numerous tissues including the brain. Members of the DAPC and dysbindin are abnormally expressed in the brain of Duchenne Muscular Dystrophy (DMD) patients, which has been associated with cognitive impairments. However, little is known about the expression pattern of individual members of the DAPC in animal models of DMD and their relationship with dysbindin. METHODS: Ten mdx mice were randomly allocated into a control and intervention group [(-)-epicatechin (Epi) 1mg/kg/day for four weeks] and results compared to a wild-type mice. After sacrifice, brain pre-frontal cortices were collected for Western blotting and immunoprecipitation assays, and sagittal sections processed for immunohistochemistry. RESULTS: Epi promotes a partial recovery of DAPC members [α1-Syntrophin, sarcoglycans (SG), dystrophin 71 (Dp71)], dysbindin, and utrophin protein levels. Epi also appears to restore the association of DAPC between dysbindin, and utrophin with Dp71 and ε-SG. Co-immunostaining evidence increased protein levels of dysbindin, dystrophin, and ε-SG and their colocalization. CONCLUSIONS: Altogether, results suggest that Epi is capable of restoring pre-frontal cortex DAPC and dysbindin levels of mdx mice towards that of healthy brains. The functional implications of such studies warrant further investigation.

Development of CAPS markers to identify Indian tea (Camellia sinensis) clones with high catechin content.

Tea leaves are rich in plant secondary phenolics, especially flavonoids. Catechins are considered to be the most valuable flavonoids, and the catechin content in tea is an important trait for determining its quality. We have developed cleaved amplified polymorphic sequence (CAPS)-based markers for evaluating total catechin content that target two important secondary metabolite pathway genes, PAL (phenylalanine ammonia-lyase) and CHS (chalcone synthase). Catechin content levels in the tea samples tested ranged from 9 to 33 mg/mg. The CAPS technique identified clones with the homozygous profile PRc1, which has relatively lower catechin content than clones with the heterozygous profile PRc2. A significant difference (t = 16.85) in the level of catechin content was also detected between heterozygotes and homozygotes in the tea seed stock TS379. We found a polynomial relationship between the marker developed for CHS2 and catechin content in these tea samples with R2 = 0.9788. Moreover, PAL has less of a relationship with catechin content. Therefore, we recommend tea clones with heterozygous CAPS profiles for the gene CHS2+RcaI for the further improvement in these clones.