RNAi activation with homologous and heterologous sequences that induce resistance against the begomovirus Pepper golden mosaic virus (PepGMV).

This study compared the transcriptional changes in Nicotiana benthamiana plants treated with homologous sequences derived from Pepper golden mosaic virus (PepGMV) and heterologous sequences that derived from another begomovirus, Tomato chino La Paz virus (ToChLPV) prior to infection by PepGMV. The results of microarray analyses identified upregulated genes associated with RNAi such as DCL2, DCL4, AGO3, AGO7, AGO10, NRPD2B (Pol IV), DRB3, CMT3, RDR6. The components that participate in different RNAi pathways were identified, including methylation induced by both constructs, as well as the code of these genes in Arabidopsis thaliana and its counterpart in N. benthamiana through different genome assembly. The expression of these genes was validated by quantitative reverse transcription polymerase chain reaction (RT-qPCR), where DCL3, DCL4, AGO1-1, AGO2, RDR6 and PPR1 showed increased expression during plant protection with the heterologous construct compared to those protected with the homologous construct. The results of this study confirmed the activation of the gene silencing mechanism at the transcriptional level with both constructs and established the possibility of their use as a protection system for both homologous and heterologous sequences.

Transcriptome analysis of Catarina scallop (Argopecten ventricosus) juveniles treated with highly-diluted immunomodulatory compounds reveals activation of non-self-recognition system.

Marine bivalve hatchery productivity is continuously challenged by apparition and propagation of new diseases, mainly those related to vibriosis. Disinfectants and antibiotics are frequently overused to prevent pathogen presence, generating a potential negative impact on the environment. Recently, the use of highly diluted compounds with immunostimulant properties in marine organisms has been trailed successfully to activate the self-protection mechanisms of marine bivalves. Despite their potential as immunostimulants, little is known about their way of action. To understand their effect, a comparative transcriptomic analysis was performed with Argopecten ventricosus juveniles. The experimental design consisted of four treatments formulated from pathogenic Vibrio lysates at two dilutions: [(T1) Vibrio parahaemolyticus and Vibrio alginolyticus 1D; (T2) V. parahaemolyticus and V. alginolyticus 7C]; minerals [(T3) PhA+SiT 7C], scorpion venom [(T4) ViT 31C]; and one control (C1) hydro-alcoholic solution (ethanol 1%). The RNA sequencing (RNAseq) analysis showed a higher modulation of differentially expressed genes (DEG) in mantle tissue compared to gill tissue. The scallops that showed a higher number of DEG related to immune response in mantle tissue corresponded to T1 (V. parahaemolyticus and V. alginolyticus lysate) and T3 (Silicea terra® - Phosphoric acid®). The transcriptome analysis allowed understanding some interactions between A. ventricosus juveniles and highly-diluted treatments.

Agrobacterium tumefaciens-transient genetic transformation of Habanero pepper (Capsicum chinense Jacq. ) leaf explants

Most of the pepper species of the genus Capsicum have been recalcitrant to efficient Agrobacterium tumefaciens-mediated stable or transient, genetic transformation. In the present work, we optimized a protocol for transient transformation of the Habanero pepper (Capsicum chinense Jacq.) through the standardization of several experimental factors. These included the age of the plants, the temperature, the length of co-cultivation, the application of a negative (vacuum) and/or a positive (infiltration) pressure, along with micro injection, the use of acetosyringone during the bacterial culturing, and modification of the pH during the GUS assay to eliminate the endogenous beta-glucuronidase activity. The standardized protocol, which yielded nearly 55 percent fully transformed leaf explants, was used to successfully mobilize two empty binary vectors (pCAMBIA2301 and pCAMex), as well as the C. chinense cDNAs encoding the pathogenesis-related protein 10 and esterase, respectively.