Effect of BvAgNP on growth, development, and glyoxalase gene expression analysis in Mammillaria bombycina and Selenicereus undatus.

BACKGROUND: Silver nanoparticles (AgNPs) have been used in plant tissue culture as growth stimulants, promoting bud initiation, germination, and rooting. In prior studies, AgNPs were synthesized and characterized by green synthesis using extracts from Beta vulgaris var. cicla (BvAgNP), and their functionality as seed disinfectant and antimicrobial was verified. In this study, we evaluated the effect of BvAgNP on the growth and development of Mammillaria bombycina and Selenicereus undatus in vitro, as well as the expression of glyoxalase genes. METHODS: Explants from M. bombycina and S. undatus in vitro were treated with 25, 50, and 100 mg/L of BvAgNP. After 90 days, morphological characteristics were evaluated, and the expression of glyoxalase genes was analyzed by qPCR. RESULTS: All treatments inhibited rooting for M. bombycina and no bud initiation was observed. S. undatus, showed a maximum response in rooting and bud generation at 25 mg/L of BvAgNP. Scanning electron microscopy (SEM) results exhibited a higher number of vacuoles in stem cells treated with BvAgNP compared to the control for both species. Expression of glyoxalase genes in M. bombycina increased in all treatments, whereas it decreased for S. undatus, however, increasing in roots. CONCLUSIONS: This study presents the effects of BvAgNP on the growth and development of M. bombycina and S. undatus, with the aim of proposing treatments that promote in vitro rooting and bud initiation.

Phytochemical Profiling of Coryphantha macromeris (Cactaceae) Growing in Greenhouse Conditions Using Ultra-High-Performance Liquid Chromatography⁻Tandem Mass Spectrometry.

Chromatographic separation combined with mass spectrometry is a powerful tool for the characterization of plant metabolites because of its high sensitivity and selectivity. In this work, the phytochemical profile of aerial and radicular parts of Coryphantha macromeris (Engelm.) Britton & Rose growing under greenhouse conditions was qualitatively investigated for the first time by means of modern ultra-high-performance liquid chromatography⁻tandem mass spectrometry (UHPLC-PDA-HESI-Orbitrap-MS/MS). The UHPLC-PDA-HESI-Orbitrap-MS/MS analysis indicated a high complexity in phenolic metabolites. In our investigation, 69 compounds were detected and 60 of them were identified. Among detected compounds, several phenolic acids, phenolic glycosides, and organic acids were found. Within this diversity, 26 metabolites were exclusively detected in the aerial part, and 19 in the roots. Twenty-four metabolites occurred in both plant parts. According to the relative abundance of peaks in the chromatogram, ferulic and piscidic acids and their derivatives may correspond to one of the main phenolic compounds of C. macromeris. Our results contribute to the phytochemical knowledge regarding C. macromeris and its potential applications in the pharmaceutical and cosmetic industries. Besides, some metabolites and their fragmentation patterns are reported here for the first time for cacti species.

De Novo Transcriptome of Mammillaria bombycina (Cactaceae) under In Vitro Conditions and Identification of Glyoxalase Genes.

Mammillaria bombycina is a cactus distributed in the central region of Mexico. Cactaceae have the particularity of surviving drought and high temperatures, which is why in vitro propagation studies have been carried out successfully to preserve this species and use it as a study model in cacti. In this contribution, a de novo transcriptome of M. bombycina was produced under in vitro conditions for the identification and expression of genes related to abiotic stress. Samples were sequenced using an Illumina platform, averaging 24 million clean readings. From assembly and annotation, 84,975 transcripts were generated, 55% of which were unigenes. Among these, the presence of 13 isoforms of genes belonging to glyoxalase I, II and III were identified. An analysis of the qRT-PCR expression of these genes was performed under in vitro and ex vitro conditions and dehydration at 6 and 24 h. The highest expression was observed under greenhouse conditions and dehydration at 24 h, according to the control. The de novo assembly of the M. bombycina transcriptome remains a study model for future work in cacti.

Micropropagation of Yucca Species.

Yuccas are plants adapted to arid and semiarid regions and have been used as source of food and raw materials and for ornamental purposes. Lately, the interest in this genus has grown due to the presence of potential useful compounds such as saponins and polyphenolics. However, they present very low reproductive rates and virtually all the plants used are wild individuals; as consequence, their natural populations have been depleted. We present an efficient method to establish in vitro cultures of Yucca species starting with seeds and then obtaining shoots from the seedling meristems using cytokinins and auxins. These shoots can be rooted and transferred to soil or can be used as explants for another multiplication cycle. Hence, it is necessary to acquire seeds just once to establish a large-scale micropropagation protocol.