Chili pepper (Capsicum annuum L.) cv. Árbol and Uvilla fruits differing in anthocyanin contents were analyzed to characterize the accumulation patterns. The maximum accumulation of the aglycon delphinidin occurred 20 days postanthesis (DPA) with higher content in Uvilla than in Árbol fruits. Regarding the cDNA library, 9 186 cDNA clones were selected. The clones with high homology to genes concerning anthocyanin biosynthesis, such as encoding chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), flavonoid 3´,5´-hydroxylase (F3´5´H), dihydroflavonol 4-reductase (DFR), anthocyanidin synthase (ANS), UDP Glc-flavonoid 3-O-gluco-syl transferase (UFGT), and also those possibly involved in anthocyanin transport into the vacuoles, an anthocyanin permease (ANP) and a glutathione S-transferase (GST) were used for gene expression analysis. In general, the expression of all investigated genes was developmentally regulated in both Árbol and Uvilla. CHS and CHI transcripts were expressed at the maximal level at 10 DPA and then consistently declined throughout fruit development. F3´5´H, DFR, UFGT and GST expression exhibited a positive correlation with anthocyanin accumulation and the highest transcript levels were detected prior to or by the time of maximum anthocyanin accumulation depending on the chili pepper type. Pericarp fruit tissues from cv. Tampiqueño 74, an anthocyanin non-accumulator, also showed CHS, CHI, F3H, ANS, and ANP expression at some developmental stages.

The molecular characterization of isolates of citrus tristeza virus (CTV) from eight locations in Mexico was undertaken by analyzing five regions located at the opposite ends of the virus genome. Two regions have been previously used to study CTV variability (coat protein and p23), while the other three correspond to other genomic segments (p349-B, p349-C and p13). Our comparative nucleotide analyses included CTV sequences from different geographical origins already deposited in the GenBank databases. The largest nucleotide differences were located in two fragments located at the 5' end of the genome (p349-B and p349-C). Phylogenetic analyses on those five regions showed that the degree of nucleotide divergence among strains tended to correlate with their pathogenicity. Two main groups were defined: mild, with almost no noticeable effects on the indicator plants and severe, with drastic symptoms. Mild isolates clustered together in every analyzed ORF sharing a genetic distance below 0.022, in contrast with the severe isolates, which showed a more disperse distribution and a genetic distance of 0.276. Analyses of the p349-B and p349-C regions evidenced two lineages within the severe group: severe common subgroup (most of severe isolates) and severe divergent subgroup (T36-like isolates). This study represents the first attempt to analyze the genetic variability of CTV in Mexico by constructing phylogenetic trees based on new genomic regions that use group-specific nucleotide and amino acid sequences. These results may be useful to implement specific assays for strain discrimination. Moreover, it would be an excellent reference for the CTV situation in México to face the recent arrival of brown citrus aphid.

Emerging infectious diseases have become a major global problem with public health and economic consequences. It is an urgent need to develop new anti-infective therapies. The natural diterpene carnosol exhibit a wide variety of interesting antibacterial and antiviral properties, and it is considered a theoretical inhibitor of COVID-19 Mpro. However, this compound is present in the family Lamiaceae in low quantities. To obtain carnosol in concentrations high enough to develop pharmacological studies, we evaluated the efficiency of a micropropagation protocol of Rosmarinus officinalis using a solid medium and a temporary immersion system (TIS), as well as the effect of 6-benzylaminopurine (6-BAP) and α-naphthaleneacetic acid (NAA) on the growth of shoots. Moreover, we developed and validated an analytical method to quantify carnosol using the H-point standard additions method in the high-performance liquid chromatography diode array detector (HPLC-DAD). After 30 days of culture, TIS produced the maximum number of shoots per explant (24.33 ± 1.15) on a liquid medium supplemented with 6-BAP at 5.0 mg L−1. Next, we also evaluated the effect of immersion time and frequency for TIS. After 72 days of culture, the best results were obtained with an immersion cycle of 1 min every 12 h, yielding 170.33 ± 29.40 shoots. The quantification of carnosol on the samples was performed at a flow rate of 1.2 mL min−1 using binary isocratic mobile phase system 60:40 (v/v) 10 mM formic acid (pH 3.0) (A) and acetonitrile (B) on a reverse-phase column. The content of carnosol in the in vitro cultures was around 8-fold higher than in the wild plant. The present study represents an efficient alternative method to obtain carnosol for its pre-clinical and clinical development.

Conservation of plant genetic resources (PGR) is essential to preserve diversity and to provide genes for plant breeding. This paper assesses the current status of pineapple PGR diversity in Cuba and actions are proposed to minimize the loss of diversity. In situ diversity was evaluated through field trips to different locations across the country, evidence was found that pineapple germplasm diversity is low. Only three (Spanish, Cayenne and Pernambuco) out of the five horticultural groups of this crop are presently planted at Cuba. Red Spanish is the predominant cultivar, and White Pineapple is an endangered one. The highest diversity was found at the Eastern region, where it was possible to find at least two different cultivars from each of these three groups. The ex situ pineapple collection contains 56 accessions, 45 % belong to the Spanish group, 20 % to Cayenne and 14 % to Pernambuco, while the rest are hybrids, improved cultivars and other related species. Threats of diversity loss were identified by the Research-Action-Participation method. Farmers and experts agreed that growing of the most common cultivars is being abandoned and consequently, there is high risk of loss of in situ diversity. Results document the low diversity of pineapple genetic resources in the country and the need to use in situ and ex situ conservation approaches as complementary strategies for germplasm preservation for future generations.

A set of minimum descriptors allow for the rapid characterisation of germplasm facilitating the conservation and use of plant material. The objective of this work was to establish a list of minimum descriptors to facilitate the morphological characterisation of the ex situ pineapple collection in Cuba. Therefore, 48 pineapple accessions were characterised according to the morphoagronomic descriptors established by the International Board for Plant Genetic Resources (IBPGR). The data were processed by Multivariate Analysis, where a Multiple Principal Components Analysis was used for the qualitative and quantitative traits. A list with 14 minimum descriptors was proposed. The leaf’s colour, the thickness of the longest leaf, the distribution of the spines, the fruit shape, the fruit colour when ripe, the flesh colour, the weight of fruit flesh, eye form, the fruit height, the fruit diameter, the fruitlet shape, the core diameter, the total soluble solids of the fruit, and the crown weight/fruit weight ratio were selected as the minimum descriptors. Because most of the descriptors refer to the pineapple’s genetic improvement or commercialisation aspects, it could be a useful tool for scientists and producers.