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White leg shrimp (Litopenaeus vannamei) is a widely cultured species along the Pacific coast and is one of the most important crustaceans in world aquaculture. The microbiome composition of L. vannamei has been previously studied in different developmental stages, but there is limited information regarding the functional role of the microbiome during the development of L. vannamei. In this study the metatranscriptome in different developmental stages of L. vannamei (larvae, juvenile and adult) were generated using next generation sequencing techniques. The bacterial phyla found throughout all the stages of development belonged to the Proteobacteria, Firmicutes and Actinobacteria, these bacterial phyla are present in the digestive tract and are capable of producing several hydrolytic enzymes, which agrees with high representation of the primary metabolism and energy production, in both host and the microbiome. In this sense, functional changes were observed as the development progressed, in both host and the microbiome, in stages of larvae the most represented metabolic functions were associated with biomass production; while in juvenile and adult stages a higher proportion of metabolic functions associated to biotic and abiotic stress in L. vannamei and the microbiome were shown. This study provides evidence of the interaction of the microbiome with L. vannamei, and how the stage of development and the culture conditions of this species influences the gene expression and the microbiome composition, which suggests a complex metabolic network present throughout the life cycle of L. vannamei.

In order to determine the role of polyamines in the formation and development of the somatic embryos of Capsicum chinense, the effect of different concentrations (0, 0.01, 0.1, and 1.0 mM) of Putrescine, Spermidine and Spermine on the efficiency and morphology of the embryos was evaluated. The results show that none of the three polyamines evaluated had a significant effect on the number of embryos formed, except Spermidine (1 mM), which caused a significant reduction in their numbers, in comparison with the control treatment. However, the most noteworthy result was observed in the treatment containing 0.1 mM of Spermine. The embryos developed in this treatment showed harmonic apex-radicle development, pale-green coloration and the formation of two tiny cotyledonary leaves. Real-time PCR was used to analyze the differential expression of the WUS, WOX1 and WOX3 genes in somatic embryos treated with Spermine and untreated, including the zygotic embryo. The transcript levels of the genes analyzed were found to differ significantly between both types of embryos (somatic and zygotic), with the zygotic embryos presenting a higher level of transcripts; however, compared to the untreated somatic embryos, the somatic embryos treated with Spermine showed an increase in the transcript levels of the three genes analyzed (WUS, WOX1 and WOX3); the WOX1 gene in particular presented an accumulation pattern similar to that of the zygotic embryo of the species.

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