Chlorophyll deficiency in Agave angustifolia Haw.: unveiling the impact on secondary metabolite production.

MAIN CONCLUSIONS: The albino phenotype of Agave angustifolia Haw. accumulates higher levels of phenylalanine and phenylpropanoids, while the green phenotype has a greater concentration of phenolic compounds. The metabolic consequences of chlorophyll deficiency in plants continue to be a captivating field of research, especially in relation to production of metabolic compounds. This study conducts a thorough analysis of the metabolome in green (G), variegated (V), and albino (A) phenotypes of Agave angustifolia Haw. Specifically, it examines the differences in the accumulation of compounds related to the phenylpropanoid and flavonoid biosynthesis pathways. Methanol extracts of leaf and meristem tissues from the three phenotypes grown in vitro were analyzed using liquid chromatography coupled with quadrupole time-of-flight high-resolution mass spectrometry (UPLC-MS-QTOF) for untargeted metabolomics and triple quadrupole (QqQ) mass spectrometry for targeted metabolomic analyses. By employing these methods, we discovered notable differences in the levels of important metabolites such as L-phenylalanine, 4-hydroxyphenylpyruvic acid, and various flavonoids among the different phenotypes. The results of our study indicate that the A phenotype shows a significant increase in the levels of phenylalanine and phenylpropanoids in both leaf and meristem tissues. This is in contrast to a decrease in flavonoids, suggesting a metabolic reprogramming to compensate for the lack of chlorophyll. Significantly, compounds such as kaempferol-3-O-glucoside and rutin exhibited significant quantitative reduction in the A leaves, suggesting a subtle modification in the production of flavonols and potentially a changed mechanism for antioxidant protection. This study emphasizes the complex metabolic changes in A. angustifolia´s chlorophyll-deficient phenotypes, providing insight into the complex interplay between primary and secondary metabolism in response to chlorophyll deficiency. Our research not only enhances the comprehension of plant metabolism in albino phenotypes but also opens new avenues for exploring the biochemical and genetic basis of such adaptations, with potential biotechnological applications of these distinct plant variants.

Biochemical and physiological time-of-day variations in early-development phase of Agave mapisaga and Agave salmiana.

This research assesses the aboveground matter accumulation and Fv/Fm ratios (maximum quantum efficiency of PSII) in young plants (5months old) of Agave mapisaga and Agave salmiana grown under greenhouse conditions. This study also evaluated changes in the relative abundance of several different metabolites (sugars, free amino acids, and soluble phenols) during the major daily phases (I, III, and IV) of Crassulacean acid metabolism (CAM). These two species were also investigated to determine if differences in these parameters were evident with respect to their geographical origins (i.e. Metepec, Tlajomulco, and Tlaxiaca, in the state of Hidalgo, Mexico). Differences in shoot mass (0.51-0.82g plant-1 ), water content (75-93%), fructose (4-27µmolg-1 ), glucose (57-73µmolg-1 ), sucrose (10-30µmolg-1 ), free amino acids (5-25µmolg-1 ), soluble phenolics (0.7-3.5µmolg-1 ), and Fv/Fm ratios (0.75-0.80) were evident between plants with different origins. Specifically, at the end of Phase I compared to Phase IV, the results showed significant reductions in dry matter (up to 3.3%) and also reductions in fructose/sucrose. Relative amino acid concentrations were lowest in Phase III (8.8µmolg-1 ) compared to Phase I (16µmolg-1 ). These are novel observations, since all these changes and the biochemical and physiological performance in the CAM phases have not been previously determined in Agave plants differing in their geographical origins.

Agave Wilt Susceptibility by Reduction of Free Hexoses in Root Tissue of Agave tequilana Weber var. azul Commercial Plants in the Fructan Accumulation Process.

Agave tequilana stems store fructan polymers, the main carbon source for tequila production. This crop takes six or more years for industrial maturity. In conducive conditions, agave wilt disease increases the incidence of dead plants after the fourth year. Plant susceptibility induced for limited photosynthates for defense is recognized in many crops and is known as "sink-induced loss of resistance". To establish whether A. tequilana is more prone to agave wilt as it ages, because the reduction of water-soluble carbohydrates in roots, as a consequence of greater assembly of highly polymerized fructans, were quantified roots sucrose, fructose, and glucose, as well as fructans in stems of agave plants of different ages. The damage induced by inoculation with Fusarium solani or F. oxysporum in the roots or xylem bundles, respectively, was recorded. As the agave plant accumulated fructans in the stem as the main sink, the amount of these hexoses diminished in the roots of older plants, and root rot severity increased when plants were inoculated with F. solani, as evidence of more susceptibility. This knowledge could help to structure disease management that reduces the dispersion of agave wilt, dead plants, and economic losses at the end of agave's long crop cycle.

Development of a tamarind-based functional beverage with partially-hydrolyzed agave syrup and the health effects of its consumption in C57BL/6 mice.

Excess consumption of sweetened beverages is associated with a global rise in metabolic diseases. Tamarind and partially-hydrolyzed agave syrup have potential for developing healthier beverages. Our objective was to develop a functional beverage using these ingredients (PH-AS-B). We also evaluate shelf-life stability (physicochemical, microbiological, and antioxidant properties) and health effects in C57BL/6 mice compared with tamarind beverages sweetened with glucose or fructose. Optimal tamarind extraction conditions were a 1:10 ratio (g pulp/mL water) and boiling for 30 min, and the resulting beverage had a shelf life of two months at 4 °C. Non-volatile metabolites were identified using HPLC/MS. PH-AS-B was associated with decreased blood cholesterol (5%) and triglyceride (20-35%) concentrations in healthy mice as well as lower lipid (82%) concentrations and evidence of protein oxidation (42%) in the liver, compared with glucose- and fructose-sweetened tamarind beverages. In conclusion, PH-AS-B was stable and associated with beneficial metabolic properties in healthy mice.

Agave amica a potential model for the study of agavins metabolism.

Fructans found in agave are called agavins, highly branched neo-fructans. They are essential on the yield and quality of Tequila production. The need for agave specimens with higher accumulation of agavins became essential before the growing demand of such products. To get such specimens, understanding agavins metabolism is a quintessential requirement. For this, a more efficient biological model is required. The recently reclassified Agave amica possesses the potential to gather the requirements for becoming such a model. Therefore, this study dealt with the characterization of carbohydrates in the bulbs of A. amica focusing on fructans. Moreover, it tested and described its feasibility as model for the accelerated study of agavins. Infrared analysis unveiled potential content of fructans in the bulbs of A. amica. Furthermore, high performance thin layer chromatography detected fructooligosaccharides. High performance anion exchange chromatography confirmed a polydisperse mixture of branched fructans. Gas chromatography-mass spectrometry analysis demonstrated agavins like structures in the bulbs of A. amica. Moreover, total fructan content and multivariate data analysis through bulb's age demonstrated their correlation. Thus, the presence of agavins, their correlation with phenology, and their technical advantages highlighted the feasibility of this species as a potential new biological model for the study of agavins' metabolism.

Rethinking the potential productivity of crassulacean acid metabolism by integrating metabolic dynamics with shoot architecture, using the example of Agave tequilana.

Terrestrial CAM plants typically occur in hot semiarid regions, yet can show high crop productivity under favorable conditions. To achieve a more mechanistic understanding of CAM plant productivity, a biochemical model of diel metabolism was developed and integrated with 3-D shoot morphology to predict the energetics of light interception and photosynthetic carbon assimilation. Using Agave tequilana as an example, this biochemical model faithfully simulated the four diel phases of CO2 and metabolite dynamics during the CAM rhythm. After capturing the 3-D form over an 8-yr production cycle, a ray-tracing method allowed the prediction of the light microclimate across all photosynthetic surfaces. Integration with the biochemical model thereby enabled the simulation of plant and stand carbon uptake over daily and annual courses. The theoretical maximum energy conversion efficiency of Agave spp. is calculated at 0.045-0.049, up to 7% higher than for C3 photosynthesis. Actual light interception, and biochemical and anatomical limitations, reduced this to 0.0069, or 15.6 Mg ha-1 yr-1 dry mass annualized over an 8-yr cropping cycle, consistent with observation. This is comparable to the productivity of many C3 crops, demonstrating the potential of CAM plants in climates where little else may be grown while indicating strategies that could raise their productivity.

Proteome of Agave angustifolia Haw.: Uncovering metabolic alterations, over-accumulation of amino acids, and compensatory pathways in chloroplast-deficient albino plantlets.

Amino acids (AA) are essential molecules for plant physiology, acting as precursor molecules for proteins and other organic compounds. Chloroplasts play a vital role in AA metabolism, yet little is known about the impact on AA metabolism of albino plants' lack of chloroplasts. In this study, we conducted a quantitative proteome analysis on albino and variegated somaclonal variants of Agave angustifolia Haw. to investigate metabolic alterations in chloroplast-deficient plants, with a focus on AA metabolic pathways. We identified 82 enzymes involved in AA metabolism, with 32 showing differential accumulation between the somaclonal variants. AaCM, AaALS, AaBCAT, AaIPMS1, AaSHMT, AaAST, AaCGS, and AaMS enzymes were particularly relevant in chloroplast-deficient Agave plantlets. Both variegated and albino phenotypes exhibited excessive synthesis of AA typically associated with chloroplasts (aromatic AAs, BCAAs, Asp, Lys, Pro and Met). Consistent trends were observed for AaBCAT and AaCM at mRNA and protein levels in albino plantlets. These findings highlight the critical activation and reprogramming of AA metabolic pathways in plants lacking chloroplasts. This study contributes to unraveling the intricate relationship between AA metabolism and chloroplast absence, offering insights into survival mechanisms of albino plants.

Lessons from the history of Agave: ecological and cultural context for valuation of CAM.

BACKGROUND AND SCOPE: Crassulacean acid metabolism (CAM) is an intriguing physiological adaptation in plants that are widespread throughout many ecosystems. Despite the relatively recent mechanistic understanding of CAM in plant physiology, evidence from historical records suggests that ancient cultures in the Americas also recognized the value of CAM plants. Agave species, in particular, have a rich cultural legacy that provides a foundation for commercially valued products. Here, we review that legacy and potential relationships between ancient values and the needs of modern-day climate adaptation strategies. CONCLUSIONS: There are many products that can be produced from Agave species, including food, sugar, fibre and medicines. Traditional knowledge about agricultural management and preparation of plant products can be combined with new ecophysiological knowledge and agronomic techniques to develop these resources in the borderland region of the southwestern USA and Mexico. Historical records of pre-Columbian practices in the Sonoran desert and remnants of centuries-old agriculture in Baja California and Sonora demonstrate the climate resilience of Agave agriculture. Commercial growth of both tequila and bacanora indicates the potential for large-scale production today, but also underscores the importance of adopting regenerative agricultural practices to accomplish environmentally sustainable production. Recent international recognition of the Appellation of Origin for several Agave species produced for spirits in Mexico might provide opportunities for agricultural diversification. In contrast, fibre is currently produced from several Agave species on many continents. Projections of growth with future climate change suggest that Agave spp. will be viable alternatives for commodity crops that suffer declines during drought and increased temperatures. Historical cultivation of Agave affirms that these CAM plants can supply sugar, soft and hard fibres, medicines and food supplements.

Symbiotic Supplementation (E. faecium and Agave Inulin) Improves Spatial Memory and Increases Plasticity in the Hippocampus of Obese Rats: A Proof-of-Concept Study.

Obesity has been linked to cognitive impairment through systemic low-grade inflammation. High fat and sugar diets (HFSDs) also induce systemic inflammation, either by induced Toll-like receptor 4 response, or by causing dysbiosis. This study aimed to evaluate the effect of symbiotics supplementation on spatial and working memory, butyrate concentration, neurogenesis, and electrophysiological recovery of HFSD-fed rats. In a first experiment, Sprague-Dawley male rats were given HFSD for 10 weeks, after which they were randomized into 2 groups (n = 10 per group): water (control), or Enterococcus faecium + inulin (symbiotic) administration, for 5 weeks. In the fifth week, spatial and working memory was analyzed through the Morris Water Maze (MWM) and Eight-Arm Radial Maze (RAM) tests, respectively, with 1 week apart between tests. At the end of the study, butyrate levels from feces and neurogenesis at hippocampus were determined. In a second experiment with similar characteristics, the hippocampus was extracted to perform electrophysiological studies. Symbiotic-supplemented rats showed a significantly better memory, butyrate concentrations, and neurogenesis. This group also presented an increased firing frequency in hippocampal neurons [and a larger N-methyl-d-aspartate (NMDA)/α-amino-3-hydroxyl-5-methyl-4-isoxazole-propionate (AMPA) current ratio] suggesting an increase in NMDA receptors, which in turn is associated with an enhancement in long-term potentiation and synaptic plasticity. Therefore, our results suggest that symbiotics could restore obesity-related memory impairment and promote synaptic plasticity.

Cranberry polyphenols and agave agavins impact gut immune response and microbiota composition while improving gut barrier function, inflammation, and glucose metabolism in mice fed an obesogenic diet.

The consumption of plant-based bioactive compounds modulates the gut microbiota and interacts with the innate and adaptive immune responses associated with metabolic disorders. The present study aimed to evaluate the effect of cranberry polyphenols (CP), rich in flavonoids, and agavins (AG), a highly branched agave-derived neo-fructans, on cardiometabolic response, gut microbiota composition, metabolic endotoxemia, and mucosal immunomodulation of C57BL6 male mice fed an obesogenic high-fat and high-sucrose (HFHS) diet for 9 weeks. Interestingly, CP+AG-fed mice had improved glucose homeostasis. Oral supplementation with CP selectively and robustly (five-fold) increases the relative abundance of Akkermansia muciniphila, a beneficial bacteria associated with metabolic health. AG, either alone or combined with CP (CP+AG), mainly stimulated the glycan-degrading bacteria Muribaculum intestinale, Faecalibaculum rodentium, Bacteroides uniformis, and Bacteroides acidifaciens. This increase of glycan-degrading bacteria was consistent with a significantly increased level of butyrate in obese mice receiving AG, as compared to untreated counterparts. CP+AG-supplemented HFHS-fed mice had significantly lower levels of plasma LBP than HFHS-fed controls, suggesting blunted metabolic endotoxemia and improved intestinal barrier function. Gut microbiota and derived metabolites interact with the immunological factors to improve intestinal epithelium barrier function. Oral administration of CP and AG to obese mice contributed to dampen the pro-inflammatory immune response through different signaling pathways. CP and AG, alone or combined, increased toll-like receptor (TLR)-2 (Tlr2) expression, while decreasing the expression of interleukin 1ß (ILß1) in obese mice. Moreover, AG selectively promoted the anti-inflammatory marker Foxp3, while CP increased the expression of NOD-like receptor family pyrin domain containing 6 (Nlrp6) inflammasome. The intestinal immune system was also shaped by dietary factor recognition. Indeed, the combination of CP+AG significantly increased the expression of aryl hydrocarbon receptors (Ahr). Altogether, both CP and AG can shape gut microbiota composition and regulate key mucosal markers involved in the repair of epithelial barrier integrity, thereby attenuating obesity-associated gut dysbiosis and metabolic inflammation and improving glucose homeostasis.

Chloroplastic pentatricopeptide repeat proteins (PPR) in albino plantlets of Agave angustifolia Haw. reveal unexpected behavior.

BACKGROUND: Pentatricopeptide repeat (PPR) proteins play an essential role in the post-transcriptional regulation of genes in plastid genomes. Although important advances have been made in understanding the functions of these genes, there is little information available on chloroplastic PPR genes in non-model plants and less in plants without chloroplasts. In the present study, a comprehensive and multifactorial bioinformatic strategy was applied to search for putative PPR genes in the foliar and meristematic tissues of green and albino plantlets of the non-model plant Agave angustifolia Haw. RESULTS: A total of 1581 PPR transcripts were identified, of which 282 were chloroplastic. Leaf tissue in the albino plantlets showed the highest levels of expression of chloroplastic PPRs. The search for hypothetical targets of 12 PPR sequences in the chloroplast genes of A. angustifolia revealed their action on transcripts related to ribosomes and translation, photosystems, ATP synthase, plastid-encoded RNA polymerase and RuBisCO. CONCLUSIONS: Our results suggest that the expression of PPR genes depends on the state of cell differentiation and plastid development. In the case of the albino leaf tissue, which lacks functional chloroplasts, it is possible that anterograde and retrograde signaling networks are severely compromised, leading to a compensatory anterograde response characterized by an increase in the expression of PPR genes.

ß(2→1) chicory and ß(2→1)-ß(2→6) agave fructans protect the human intestinal barrier function in vitro in a stressor-dependent fashion.

Dietary fibers such as fructans can protect the intestinal epithelial barrier integrity, but the mechanisms underlying this protection are not completely understood. We aimed to study the protective effect of ß(2→1)-ß(2→6) branched graminan-type fructans (GTFs) on gut epithelial barrier function that was disrupted by three different agents which impact the barrier function via different cellular mechanisms. The effects of GTFs were compared with those of linear ß(2→1) inulin-type fructans (ITFs). T84 intestinal epithelial monolayers were incubated with GTFs and ITFs. Afterwards, the monolayers were challenged with the barrier disruptors calcium ionophore A23187, 12-myristate 13-acetate (PMA) and deoxynivalenol (DON). Transepithelial resistance was measured with an electric cell-substrate impedance sensing system. All fructans studied prevented the barrier disruption induced by A23187. ITF II protected from the disruptive effects of PMA. However, none of the studied fructans influenced the disruption induced by DON. As a measure of disruption-induced inflammation, interleukin-8 (IL-8) production by the intestinal epithelium was determined by ELISA. The production of IL-8 induced by A23187 was decreased by all fructans, whereas IL-8 production induced by DON decreased only upon pre-treatment with ITF II. None of the studied fructans prevented PMA induced IL-8 production. GTFs just like ITFs can influence the barrier function and inflammatory processes in gut epithelial cells in a structure-dependent fashion. These distinct protective effects are dependent on the different signaling pathways that lead to gut barrier disruption.

Hunting Bioactive Molecules from the Agave Genus: An Update on Extraction and Biological Potential.

Agaves are plants used in the production of alcoholic beverages and fibers. Ever since ancient times, pre-Hispanic cultures in Mexico have used them in traditional medicine to cure different ailments. Over the years, studies of the active principles responsible for the therapeutic benefits of agaves have increased. Leaves and fibers are the main agro-wastes generated in tequila and mezcal production, while fibers are the main waste product in the textile sector. Different investigations have referred to the agro-waste from agave processing as a source of bioactive molecules called secondary metabolites (SM). Among them, phenols, flavonoids, phytosterols, and saponins have been extracted, identified, and isolated from these plants. The role of these molecules in pest control and the prospect of metabolites with the biological potential to develop novel drugs for chronic and acute diseases represent new opportunities to add value to these agro-wastes. This review aims to update the biological activities and recent applications of the secondary metabolites of the genus Agave.

Role of xylose from acidic hydrolysates of agave bagasse during biohydrogen production.

This study compares the H2 production from glucose, xylose, and acidic hydrolysates of Agave tequilana bagasse as substrates. The fermentation was performed in a granular sludge reactor operated in two phases: (1) model substrates (glucose and xylose) and (2) acidic hydrolysates at 35 °C, pH 4.5 and a hydraulic retention time of 5.5 h with glucose (10 g L-1) and xylose (12 g L-1). A sequencing batch reactor was used to acclimate the biomass between the glucose and xylose continuous fermentation (with a mixture of xylose-glucose) and acidic hydrolysates. During the discontinuous acclimating step, the xylose/glucose ratio increment negatively affected the H2 productivity. Although the continuous H2 production with xylose was negligible, the co-fermentation with glucose (88-12%) allowed H2 productivity of 2,889 ± 502 mL H2 L-1d-1. An acidic hydrolysate concentration of 3.3 gcarbohydrate L-1 showed a three-fold higher H2 productivity than with a concentration of 10 g L-1. The results indicated that xylose, as the only substrate, was challenging to metabolize by the inoculum, and its mixture with glucose improved the H2 productivity. Therefore, the low H2 productivity with hydrolysates could be related to the presence of xylose.

Revealing floral metabolite network in tuberose that underpins scent volatiles synthesis, storage and emission.

KEY MESSAGE: The role of central carbon metabolism in the synthesis and emission of scent volatiles in tuberose flowers was revealed through measurement of changes in transcripts and metabolites levels. Tuberose or Agave amica (Medikus) Thiede & Govaerts is a widely cultivated ornamental plant in several subtropical countries. Little is known about metabolite networking involved in biosynthesis of specialized metabolites utilizing primary metabolites. In this study, metabolite profiling and gene expression analyses were carried out from six stages of maturation throughout floral lifespan. Multivariate analysis indicated distinction between early and late maturation stages. Further, the roles of sugars viz. sucrose, glucose and fructose in synthesis, glycosylation and emission of floral scent volatiles were studied. Transcript levels of an ABC G family transporter (picked up from the floral transcriptome) was in synchronization with terpene volatiles emission during the anthesis stage. A diversion from phenylpropanoid/benzenoid to flavonoid metabolism was observed as flowers mature. Further, it was suggested that this metabolic shift could be mediated by isoforms of 4-Coumarate-CoA ligase along with Myb308 transcription factor. Maximum glycosylation of floral scent volatiles was shown to occur at the late mature stage when emission declined, facilitating both storage and export from the floral tissues. Thus, this study provides an insight into floral scent volatiles synthesis, storage and emission by measuring changes at transcripts and metabolites levels in tuberose throughout floral lifespan.

A validated strategy to design efficient fermentation-industrial processes: agave spirit production.

An industrial process is profitable when its individual unit operations are efficient and thus, this work shows a guideline for designing efficient fermentation-industrial processes for agave distilled production based on a sequential approach of optimization, beginning in the laboratory and followed by the adjustment of the variable values using the evolutionary operation method for successful process scaling. The results at the laboratory showed that a starter inoculum containing a 5 × 106 cells/mL mixture of Kluyveromyces marxianus, Clavispora lusitaniae, and Kluyveromyces marxianus var. drosophilarum strains in a bioreactor containing agave syrup with 120 g/L fermented sugar, processed at a constant temperature of 33 °C and 1.0 VVM aeration for 1.6 h, led to a fermented product with a 4.18% (v/v) alcohol content after 72 h of processing time. The scale-up process results showed that the best operating conditions at the pilot-plant level were a temperature of 35 °C and aeration at 1.0 VVM for 1.2 h, which led to a fermented product with a 4.22% (v/v) total alcohol content after 72 h of processing time. These represent similar performance values for both production processes, but each one worked with their specific values of process variables, which demonstrates that each level of production had its own specific values for process variables. The volatile compound analysis shows that both distilled products contained a similar profile of volatile components that provide fruity and ethereal aromatic notes pleasant to the palate. Therefore, the process design for agave spirit production at the semi-industrial level was successfully achieved.

Overexpression of an Agave Phosphoenolpyruvate Carboxylase Improves Plant Growth and Stress Tolerance.

It has been challenging to simultaneously improve photosynthesis and stress tolerance in plants. Crassulacean acid metabolism (CAM) is a CO2-concentrating mechanism that facilitates plant adaptation to water-limited environments. We hypothesized that the ectopic expression of a CAM-specific phosphoenolpyruvate carboxylase (PEPC), an enzyme that catalyzes primary CO2 fixation in CAM plants, would enhance both photosynthesis and abiotic stress tolerance. To test this hypothesis, we engineered a CAM-specific PEPC gene (named AaPEPC1) from Agave americana into tobacco. In comparison with wild-type and empty vector controls, transgenic tobacco plants constitutively expressing AaPEPC1 showed a higher photosynthetic rate and biomass production under normal conditions, along with significant carbon metabolism changes in malate accumulation, the carbon isotope ratio δ13C, and the expression of multiple orthologs of CAM-related genes. Furthermore, AaPEPC1 overexpression enhanced proline biosynthesis, and improved salt and drought tolerance in the transgenic plants. Under salt and drought stress conditions, the dry weight of transgenic tobacco plants overexpressing AaPEPC1 was increased by up to 81.8% and 37.2%, respectively, in comparison with wild-type plants. Our findings open a new door to the simultaneous improvement of photosynthesis and stress tolerance in plants.

Transcriptome-based metabolic profiling of flavonoids in Agave lechuguilla waste biomass.

Agave lechuguilla is one of the most abundant species in arid and semiarid regions of Mexico, and is used to extract fiber. However, 85 % of the harvested plant material is discarded. Previous bioprospecting studies of the waste biomass suggest the presence of bioactive compounds, although the extraction process limited metabolite characterization. This work achieved flavonoid profiling of A. lechuguilla in both processed and non-processed leaf tissues using transcriptomic analysis. Functional annotation of the first de novo transcriptome of A. lechuguilla (255.7 Mbp) allowed identifying genes coding for 33 enzymes and 8 transcription factors involved in flavonoid biosynthesis. The flavonoid metabolic pathway was mostly elucidated by HPLC-MS/MS screening of alcoholic extracts. Key genes of flavonoid synthesis were higher expressed in processed leaf tissues than in non-processed leaves, suggesting a high content of flavonoids and glycoside derivatives in the waste biomass. Targeted HPLC-UV-MS analyses confirmed the concentration of isorhamnetin (1251.96 µg), flavanone (291.51 µg), hesperidin (34.23 µg), delphinidin (24.23 µg), quercetin (15.57 µg), kaempferol (13.71 µg), cyanidin (12.32 µg), apigenin (9.70 µg) and catechin (7.91 µg) per gram of dry residue. Transcriptomic and biochemical profiling concur in the potential of lechuguilla by-products with a wide range of applications in agriculture, feed, food, cosmetics, and pharmaceutical industries.

Utilization of Agave durangensis leaves by Bacillus cereus 4N for polyhydroxybutyrate (PHB) biosynthesis.

Lignocellulosic wastes may provide a means to economize polyhydroxybutyrate (PHB) production. This study has proposed the use of Agave durangensis leaves obtained from the artisanal mezcal industry as a novel substrate for this aim. Results revealed an increase in PHB biosynthesis (0.32 g/L) and improvement in %PHB (16.79-19.51%) by Bacillus cereus 4N when A. durangensis leaves used as carbon source were physically pre-treated by ultrasound for 30 min (ADL + US30') and thermally pre-treated (ADL + Q). Chemical analyses and SEM studies revealed compositional and morphological changes when A. durangensis leaves were physically pre-treated. Also, elemental analysis of growth media showed that carbon/nitrogen ratios of 14-21, and low nitrogen, hydrogen, and protein content were well-suited for PHB biosynthesis. Confocal microscopy revealed morphological changes in the bacterial cell and carbonosome structure under the influence of different substrates. Finally, Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) analyses showed that homopolymeric PHB with a high thermal-resistance (271.94-272.89 °C) was produced. Therefore, the present study demonstrates the potential use of physically pre-treated A. durangensis leaves to produce PHB. These results promote the development of a circular economy in Mexico, where lignocellulosic wastes can be employed to produce value-added biotechnological products.

Modelling nonlinear dynamics of Crassulacean acid metabolism productivity and water use for global predictions.

Crassulacean acid metabolism (CAM) crops are important agricultural commodities in water-limited environments across the globe, yet modelling of CAM productivity lacks the sophistication of widely used C3 and C4 crop models, in part due to the complex responses of the CAM cycle to environmental conditions. This work builds on recent advances in CAM modelling to provide a framework for estimating CAM biomass yield and water use efficiency from basic principles. These advances, which integrate the CAM circadian rhythm with established models of carbon fixation, stomatal conductance and the soil-plant-atmosphere continuum, are coupled to models of light attenuation, plant respiration and biomass partitioning. Resulting biomass yield and transpiration for Opuntia ficus-indica and Agave tequilana are validated against field data and compared with predictions of CAM productivity obtained using the empirically based environmental productivity index. By representing regulation of the circadian state as a nonlinear oscillator, the modelling approach captures the diurnal dynamics of CAM stomatal conductance, allowing the prediction of CAM transpiration and water use efficiency for the first time at the plot scale. This approach may improve estimates of CAM productivity under light-limiting conditions when compared with previous methods.