Molecular Insights into the Role of Sterols in Microtuber Development of Potato Solanum tuberosum L.

Potato tubers are reproductive and storage organs, enabling their survival. Unraveling the molecular mechanisms that regulate tuberization is crucial for understanding how potatorespond to environmental stress situations and for potato breeding. Previously, we did a transcriptomic analysis of potato microtuberization without light. This showed that important cellular processes like ribosomal proteins, cell cycle, carbon metabolism, oxidative stress, fatty acids, and phytosterols (PS) biosynthesis were closely connected in a protein-protein interaction (PPI) network. Research on PS function during potato tuberization has been scarce. PS plays a critical role in regulating membrane permeability and fluidity, and they are biosynthetic precursors of brassinosteroids (BRs) in plants, which are critical in regulating gene expression, cell division, differentiation, and reproductive biology. Within a PPI network, we found a module of 15 genes involved in the PS biosynthetic process. Darkness, as expected, activated the mevalonate (MVA) pathway. There was a tight interaction between three coding gene products for HMGR3, MVD2, and FPS1, and the gene products that synthetize PS, including CAS1, SMO1, BETAHSD, CPI1, CYP51, FACKEL, HYDRA1, SMT2, SMO2, STE1, and SSR1. Quantitative real-time polymerase chain reaction (qRT-PCR) confirmed the expression analysis of ten specific genes involved in the biosynthesis of PS. This manuscript discusses the potential role of genes involved in PS biosynthesis during microtuber development.

Exploring the Potential Role of Ribosomal Proteins to Enhance Potato Resilience in the Face of Changing Climatic Conditions.

Potatoes have emerged as a key non-grain crop for food security worldwide. However, the looming threat of climate change poses significant risks to this vital food source, particularly through the projected reduction in crop yields under warmer temperatures. To mitigate potential crises, the development of potato varieties through genome editing holds great promise. In this study, we performed a comprehensive transcriptomic analysis to investigate microtuber development and identified several differentially expressed genes, with a particular focus on ribosomal proteins-RPL11, RPL29, RPL40 and RPL17. Our results reveal, by protein-protein interaction (PPI) network analyses, performed with the highest confidence in the STRING database platform (v11.5), the critical involvement of these ribosomal proteins in microtuber development, and highlighted their interaction with PEBP family members as potential microtuber activators. The elucidation of the molecular biological mechanisms governing ribosomal proteins will help improve the resilience of potato crops in the face of today's changing climatic conditions.

Pharmacognostic Study, Diuretic Activity and Acute Oral Toxicity of the Leaves of Xiphidium caeruleum Aubl. Collected in Two Different Phenological Stages.

Xiphidium caeruleum Aubl. is traditionally used in Cuba as an analgesic, anti-inflammatory, antilithiatic and diuretic remedy. Here we studied the pharmacognostic parameters of the leaves of X. caeruleum, the preliminary phytochemical composition, diuretic activity and acute oral toxicity of the aqueous extracts from the leaves of plants collected in the vegetative (VE) and flowering (FE) stages. The morphological characteristics and physicochemical parameters of leaves and extracts were determined. The phytochemical composition was assessed by phytochemical screening, TLC, UV, IR and HPLC/DAD profiles. The diuretic activity was evaluated in Wistar rats and compared to furosemide, hydrochlorothiazide and spironolactone. Epidermal cells, stomata and crystals were observed on the leaf surface. Phenolic compounds were identified as the main metabolites, including phenolic acids (gallic, caffeic, ferulic and cinnamic acids) and flavonoids (catechin, kaempferol-3-O-glucoside and quercetin). VE and FE showed diuretic activity. The activity of VE was similar to furosemide, and the activity of FE resembled spironolactone. No acute oral toxicity was observed. The presence of flavonoids and phenols in VE and FE may explain at least in part the traditional use and provide some insight into the reported ethnomedical use as a diuretic. Because of the differences in polyphenol profiles between VE and FE, further studies should be carried out to standardize the harvesting and extraction conditions in order to use X. caeruleum leaf extract as herbal medicine.

Solanum tuberosum Microtuber Development under Darkness Unveiled through RNAseq Transcriptomic Analysis.

Potato microtuber (MT) development through in vitro techniques are ideal propagules for producing high quality potato plants. MT formation is influenced by several factors, i.e., photoperiod, sucrose, hormones, and osmotic stress. We have previously developed a protocol of MT induction in medium with sucrose (8% w/v), gelrite (6g/L), and 2iP as cytokinin under darkness. To understand the molecular mechanisms involved, we performed a transcriptome-wide analysis. Here we show that 1715 up- and 1624 down-regulated genes were involved in this biological process. Through the protein-protein interaction (PPI) network analyses performed in the STRING database (v11.5), we found 299 genes tightly associated in 14 clusters. Two major clusters of up-regulated proteins fundamental for life growth and development were found: 29 ribosomal proteins (RPs) interacting with 6 PEBP family members and 117 cell cycle (CC) proteins. The PPI network of up-regulated transcription factors (TFs) revealed that at least six TFs-MYB43, TSF, bZIP27, bZIP43, HAT4 and WOX9-may be involved during MTs development. The PPI network of down-regulated genes revealed a cluster of 83 proteins involved in light and photosynthesis, 110 in response to hormone, 74 in hormone mediate signaling pathway and 22 related to aging.

In Vitro Culture of Rosmarinus officinalis L. in a Temporary Immersion System: Influence of Two Phytohormones on Plant Growth and Carnosol Production.

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.

Gene Expression Analysis of Microtubers of Potato Solanum tuberosum L. Induced in Cytokinin Containing Medium and Osmotic Stress.

Potato microtuber productions through in vitro techniques are ideal propagules for producing high quality seed potatoes. Microtuber development is influenced by several factors, i.e., high content sucrose and cytokinins are among them. To understand a molecular mechanism of microtuberization using osmotic stress and cytokinin signaling will help us to elucidate this process. We demonstrate in this work a rapid and efficient protocol for microtuber development and gene expression analysis. Medium with high content of sucrose and gelrite supplemented with 2iP as cytokinin under darkness condition produced the higher quantity and quality of microtubers. Gene expression analysis of genes involved in the two-component signaling system (StHK1), cytokinin signaling, (StHK3, StHP4, StRR1) homeodomains (WUSCHEL, POTH1, BEL5), auxin signaling, ARF5, carbon metabolism (TPI, TIM), protein synthesis, NAC5 and a morphogenetic regulator of tuberization (POTH15) was performed by qPCR real time. Differential gene expression was observed during microtuber development. Gene regulation of two component and cytokinin signaling is taking place during this developmental process, yielding more microtubers. Further analysis of each component is required to elucidate it.

Sequence diversity on four ORFs of citrus tristeza virus correlates with pathogenicity.

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.