Exploring ascomycete diversity in Yunnan II: Introducing three novel species in the suborder Massarineae (Dothideomycetes, Pleosporales) from fern and grasses.

This article presents the results of an ongoing inventory of Ascomycota in Yunnan, China, carried out as part of the research project series "Exploring ascomycete diversity in Yunnan". From over 100 samples collected from diverse host substrates, microfungi have been isolated, identified and are currently being documented. The primary objective of this research is to promote the discovery of novel taxa and explore the ascomycete diversity in the region, utilising a morphology-phylogeny approach. This article represents the second series of species descriptions for the project and introduces three undocumented species found in the families Bambusicolaceae, Dictyosporiaceae and Periconiaceae, belonging to the suborder Massarineae (Pleosporales, Dothideomycetes). These novel taxa exhibit typical morphological characteristics of Bambusicola, Periconia and Trichobotrys, leading to their designation as Bambusicolahongheensis, Periconiakunmingensis and Trichobotryssinensis. Comprehensive multigene phylogenetic analyses were conducted to validate the novelty of these species. The results revealed well-defined clades that are clearly distinct from other related species, providing robust support for their placement within their respective families. Notably, this study unveils the phylogenetic affinity of Trichobotrys within Dictyosporiaceae for the first time. Additionally, the synanamorphism for the genus Trichobotrys is also reported for the first time. Detailed descriptions, illustrations and updated phylogenies of the novel species are provided, and thus presenting a valuable resource for researchers and mycologists interested in the diversity of ascomycetes in Yunnan. By enhancing our understanding of the Ascomycota diversity in this region, this research contributes to the broader field of fungal taxonomy and their phylogenetic understanding.

Turning weeds into feed: Ensiling Calotropis gigantea (Giant milkweed) reduces its toxicity and enhances its palatability for dairy cows.

Calotropis gigantea (Giant milkweed, GM) has the potential to be utilized as a new feed additive for ruminants, however, the presence of unpalatable or toxic compounds decreases animal feed intake. This study aimed to valorize GM as a potential new feed resource through the chemical and microbial biotransformation of toxic compounds that will henceforth, make the plant palatable for cows. After GM's ensiling using fermentative bacteria, the plant was sampled for UHPLC-MS/MS to analyse the metabolomic changes. Illumina Miseq of the 16 S rRNA fragment genes and ITS1 were used to describe the microbial composition and structure colonizing GM silage and contributing to the biodegradation of toxic compounds. Microbial functions were predicted from metataxonomic data and KEGG pathways analysis. Eight Holstein dairy cows assigned in a cross-over design were supplemented with GM and GM silage to evaluate palatability and effects on milk yield and milk protein. Cows were fed their typical diet prior to the experiment (positive control). After ensiling, 23 flavonoids, 47 amino acids and derivatives increased, while the other 14 flavonoids, 9 amino acids and derivatives decreased, indicating active metabolism during the GM ensiling process. Lactobacillus buchneri, Bacteroides ovatus, and Megasphaera elsdenii were specific to ensiled GM and correlated to functional plant metabolites, while Sphingomonas paucimobilis and Staphylococcus saprophyticus were specific to non-ensiled GM and correlated to the toxic metabolite 5-hydroxymethylfurfural."Xenobiotics biodegradation and metabolism", "cancer overview" and "neurodegenerative disease" were the highly expressed microbial KEGG pathways in non-ensiled GM. Non-ensiled GM is unpalatable for cows and drastically reduces the animal's feed intake, whereas ensiled GM does not reduce feed intake, milk yield and milk protein. This study provides essential information for sustainable animal production by valorizing GM as a new feed additive.

Could soil microplastic pollution exacerbate climate change? A meta-analysis of greenhouse gas emissions and global warming potential.

Microplastics pollution and climate change are primarily investigated in isolation, despite their joint threat to the environment. Greenhouse gases (GHGs) are emitted during: the production of plastic and rubber, the use and degradation of plastic, and after contamination of environment. This is the first meta-analysis to assess underlying causal relationships and the influence of likely mediators. We included 60 peer-reviewed empirical studies; estimating GHGs emissions effect size and global warming potential (GWP), according to key microplastics properties and soil conditions. We investigated interrelationships with microbe functional gene expression. Overall, microplastics contamination was associated with increased GHGs emissions, with the strongest effect (60%) on CH4 emissions. Polylactic-acid caused 32% higher CO2 emissions, but only 1% of total GWP. Phenol-formaldehyde had the greatest (175%) GWP via 182% increased N2O emissions. Only polystyrene resulted in reduced GWP by 50%, due to N2O mitigation. Polyethylene caused the maximum (60%) CH4 emissions. Shapes of microplastics differed in GWP: fiber had the greatest GWP (66%) whereas beads reduced GWP by 53%. Films substantially increased emissions of all GHGs: 14% CO2, 10% N2O and 60% CH4. Larger-sized microplastics had higher GWP (125%) due to their 9% CO2 and 63% N2O emissions. GWP rose sharply if soil microplastics content exceeded 0.5%. Higher CO2 emissions, ranging from 4% to 20%, arose from soil which was either fine, saturated or had high-carbon content. Higher N2O emissions, ranging from 10% to 95%, arose from soils that had either medium texture, saturated water content or low-carbon content. Both CO2 and N2O emissions were 43%-56% higher from soils with neutral pH. We conclude that microplastics contamination can cause raised GHGs emissions, posing a risk of exacerbating climate-change. We show clear links between GHGs emissions, microplastics properties, soil characteristics and soil microbe functional gene expression. Further research is needed regarding underlying mechanisms and processes.

Integrated ultrastructural, physiological, transcriptomic, and metabolomic analysis uncovers the mechanisms by which nicotinamide alleviates cadmium toxicity in Pistia stratiotes L.

Exogenous nicotinamide (NIC) is a promising solution to relieve heavy metal (HM) toxicity in plants. Nonetheless, the underlying mechanisms involved remain poorly understood. As NIC addition (200 µM) can increase the tolerance of Pistia stratiotes L. to Cd stress (10 mg L-1), this strategy was subjected to integrated ultrastructural, physiological, transcriptomic, and metabolomic analysis to reveal the mechanisms involved. Exogenous NIC initiated a series of physiological, transcriptional, and metabolic responses that alleviated Cd damage. NIC addition improved Cd transfer from roots to leaves and reduced Cd damage in roots. The transported Cd to leaves did not induce further toxicity because it was abundantly compartmentalised in cell walls, which might be mediated by lignin synthesis. Moreover, NIC addition improved the repair of photosystem II in leaves under Cd stress by inducing key genes (e.g., chlorophyll A-B binding protein and PSII repair protein encoding genes), resulting in the restoration of Fv/Fm. In addition, antioxidant enzyme activities (e.g., peroxidase and catalase) and synthesis of antioxidants (e.g., stachydrine and curculigoside) were triggered to overcome oxidative stress. Our work paves the way for a deeper understanding of the mechanisms by which NIC alleviates HM toxicity in plants, providing a basis for improving phytoremediation.

Nano-Iron Oxide (Fe3O4) Mitigates the Effects of Microplastics on a Ryegrass Soil-Microbe-Plant System.

To understand microplastic-nanomaterial interactions in agricultural systems, a randomized block 90-day pot experiment was set up to cultivate ryegrass seedings in a typical red sandy soil amended with compost (1:9 ratio). Polyvinyl chloride (PVC) and polyethylene (PE) microplastic (MP) contaminants were added into pot soils at 0.1 and 10%, whereas nano-Fe3O4 (as nanoenabled agrochemicals) was added at 0.1% and 0.5% in comparison with chemical-free controls. The combination of nano-Fe3O4 and MPs significantly increased the soil pH (+3% to + 17%) but decreased the total nitrogen content (-9% to - 30%; P < 0.05). The treatment group with both nano-Fe3O4 and PE had the highest total soil C (29 g kg-1 vs 20 g kg-1 in control) and C/N ratio (13 vs 8 in control). Increased rhizosphere nano-Fe3O4 concentrations promoted ryegrass growth (+42% dry weight) by enhancing the chlorophyll (+20%) and carotenoid (+15%) activities. Plant leaf and root peroxidase enzyme activity was more significantly affected by nano-Fe3O4 with PVC (+15%) than with PE (+6%). Nano-Fe3O4 significantly changed the ryegrass bacterial community structure from belowground (the rhizoplane and root endosphere) to aboveground (the phylloplane). Under MP contamination, the addition of nano-Fe3O4 increased bacterial diversity (+0.35%) and abundance (+30%) in the phylloplane and further intensified the connectivity of ryegrass aboveground bacterial networks (positive association increased 17%). The structural equation model showed that the change in the plant microbiome was associated with the rhizosphere microbiome. Overall, these findings imply the positive influences of nano-Fe3O4 on the soil-microbe-plant system and establish a method to alleviate the harmful effects of MP accumulation in soils.

Gamma-Aminobutyric Acid Enhances Cadmium Phytoextraction by Coreopsis grandiflora by Remodeling the Rhizospheric Environment.

Gamma-aminobutyric acid (GABA) significantly affects plant responses to heavy metals in hydroponics or culture media, but its corresponding effects in plant-soil systems remain unknown. In this study, different GABA dosages (0-8 g kg-1) were added to the rhizosphere of Coreopsis grandiflora grown in Cd-contaminated soils. Cd accumulation in the shoots of C. grandiflora was enhanced by 38.9-159.5% by GABA in a dose-dependent approach because of accelerated Cd absorption and transport. The increase in exchangeable Cd transformed from Fe-Mn oxide and carbonate-bound Cd, which may be mainly driven by decreased soil pH rather than GABA itself, could be a determining factor responsible for this phenomenon. The N, P, and K availability was affected by multiple factors under GABA treatment, which may regulate Cd accommodation and accumulation in C. grandiflora. The rhizospheric environment dynamics remodeled the bacterial community composition, resulting in a decline in overall bacterial diversity and richness. However, several important plant growth-promoting rhizobacteria, especially Pseudomonas and Sphingomonas, were recruited under GABA treatment to assist Cd phytoextraction in C. grandiflora. This study reveals that GABA as a soil amendment remodels the rhizospheric environment (e.g., soil pH and rhizobacteria) to enhance Cd phytoextraction in plant-soil systems.

Identification of the carotenoid cleavage dioxygenase genes and functional analysis reveal DoCCD1 is potentially involved in beta-ionone formation in Dendrobium officinale.

The carotenoids are the most widely distributed secondary metabolites in plants and can be degraded by carotenoid cleavage dioxygenase (CCD) to form apocarotenoids including an important C13 compound beta-ionone. Volatile beta-ionone can confer the violet and woody fragrance to plant essential oils, flowers, fruits, and vegetables, which therefore has been used in various industries. Dendrobium officinale is a traditional medicinal plant. However, there was limited information on the key enzymes involved in the biosynthesis of beta-ionone in D. officinale. In the present study, beta-ionone was detected in stems and leaves of D. officinale and genome-wide identification and expression profiles of CCD genes were subsequently carried out. There were nine DoCCD members in D. officinale. According to the phylogenetic relationship, DoCCD proteins were classified into six subfamilies including CCD1, CCD4, CCD7, CCD8, nine-cis-epoxycarotenoid dioxygenase (NCED) and zaxinone synthase (ZAS). DoCCD genes showed distinctive expression profiles and DoCCD1 gene was abundantly expressed in eight tissues. Induced expression of DoCCD1 gene resulted in discoloration of Escerichia coli strains that can accumulate carotenoids. Analysis of Gas Chromatography/Mass Spectrometer showed that DoCCD1 enzyme can cleave lycopene to produce 6-methyl-5-hepten-2-one and pseudoionone and also catalyze beta-carotene to form beta-ionone. Expression of DoCCD1 gene in Nicotiana benthamiana leaf resulted in production of abundant beta-ionone. Overall, the present study first provides valuable information on the CCD gene family in D. officinale, function of DoCCD1 gene as well as production of beta-ionone through genetic modification.

Polyaspartic acid enhances the Cd phytoextraction efficiency of Bidens pilosa by remolding the rhizospheric environment and reprogramming plant metabolism.

The green soil chelator polyaspartic acid (PASP) can enhance heavy metal phytoextraction efficiency, but the potential mechanisms are not clearly understood from the whole soil-plant system. In this study, we explored the effects and potential mechanisms of PASP addition in soils on plant growth and cadmium (Cd) uptake in the Cd hyperaccumulator Bidens pilosa by analysing variations in chemical elements, rhizospheric microbial community, and plant metabolomics. The results showed that PASP significantly promoted the biomass yield and Cd concentration in B. pilosa, leading to an increase in the total accumulated Cd by 46.4% and 76.4% in shoots and 124.7% and 197.3% in roots under 3 and 6 mg kg-1 PASP addition, respectively. The improved soil-available nutrients and enriched plant growth-promoting rhizobacteria (e.g., Sphingopyxis, Sphingomonas, Cupriavidus, Achromobacter, Nocardioides, and Rhizobium) were probably responsible for the enhanced plant growth after PASP addition. The increase in Cd uptake by plants could be due to the improved rhizosphere-available Cd, which was directly activated by PASP and affected by the induced rhizobacteria involved in immobilizing/mobilizing Cd (e.g., Sphingomonas, Cupriavidus, Achromobacter, and Rhizobium). Notably, PASP and/or these potassium (K)-solubilizing rhizobacteria (i.e., Sphingomonas, Cupriavidus, and Rhizobium) highly activated rhizosphere-available K to enhance plant growth and Cd uptake in B. pilosa. Plant physiological and metabolomic results indicated that multiple processes involving antioxidant enzymes, amino acids, organic acids, and lipids contributed to Cd detoxification in B. pilosa. This study provides novel insights into understanding how soil chelators drive heavy metal transfer in soil-plant systems.

Quantitative Succinyl-Proteome Profiling of Turnip (Brassica rapa var. rapa) in Response to Cadmium Stress.

Protein post-translational modification (PTM) is an efficient biological mechanism to regulate protein structure and function, but its role in plant responses to heavy metal stress is poorly understood. The present study performed quantitative succinyl-proteome profiling using liquid chromatography−mass spectrometry analysis to explore the potential roles of lysine succinylation modification in turnip seedlings in response to cadmium (Cd) stress (20 µM) under hydroponic conditions over a short time period (0−8 h). A total of 547 succinylated sites on 256 proteins were identified in the shoots of turnip seedlings. These succinylated proteins participated in various biological processes (e.g., photosynthesis, tricarboxylic acid cycle, amino acid metabolism, and response to stimulation) that occurred in diverse cellular compartments according to the functional classification, subcellular localization, and protein interaction network analysis. Quantitative analysis showed that the intensities of nine succinylation sites on eight proteins were significantly altered (p < 0.05) in turnip shoots after 8 h of Cd stress. These differentially succinylated sites were highly conserved in Brassicaceae species and mostly located in the conserved domains of the proteins. Among them, a downregulated succinylation site (K150) in the glycolate oxidase protein (Gene0282600.1), an upregulated succinylation site (K396) in the catalase 3 protein (Gene0163880.1), and a downregulated succinylation site (K197) in the glutathione S-transferase protein (Gene0315380.1) may have contributed to the altered activity of the corresponding enzymes, which suggests that lysine succinylation affects the Cd detoxification process in turnip by regulating the H2O2 accumulation and glutathione metabolism. These results provide novel insights into understanding Cd response mechanisms in plants and important protein modification information for the molecular-assisted breeding of Brassica varieties with distinct Cd tolerance and accumulation capacities.

Physiological and rhizospheric response characteristics to cadmium of a newly identified cadmium accumulator Coreopsis grandiflora Hogg. (Asteraceae).

Screening for superior cadmium (Cd) phytoremediation resources and uncovering the mechanisms of plant response to Cd are important for effective phytoremediation of Cd-polluted soils. In this study, the characteristics of Coreopsis grandiflora related to Cd tolerance and accumulation were analyzed to evaluate its Cd phytoremediation potential. The results revealed that C. grandiflora can tolerate up to 20 mg kg-1 of Cd in the soil. This species showed relatively high shoot bioconcentration factors (1.09-1.85) and translocation factors (0.46-0.97) when grown in soils spiked with 5-45 mg kg-1 Cd, suggesting that C. grandiflora is a Cd accumulator and can potentially be used for Cd phytoextraction. Physiological analysis indicated that antioxidant enzymes (i.e., superoxide dismutase, peroxidase, and catalase) and various free amino acids (e.g., proline, histidine, and methionine) participate in Cd detoxification in C. grandiflora grown in soil spiked with 20 mg kg-1 of Cd (Cd20). The overall microbial richness and diversity remained similar between the control (Cd0) and Cd20 soils. However, the abundance of multiple rhizospheric microbial taxa was altered in the Cd20 soil compared with that in the Cd0 soil. Interestingly, many plant growth-promoting microorganisms (e.g., Nocardioides, Flavisolibacter, Rhizobium, Achromobacter, and Penicillium) enriched in the Cd20 soil likely contributed to the growth and vitality of C. grandiflora under Cd stress. Among these, some microorganisms (e.g., Rhizobium, Achromobacter, and Penicillium) likely affected Cd uptake by C. grandiflora. These abundant plant growth-promoting microorganisms potentially interacted with soil pH and the concentrations of Cd and AK in soil. Notably, potassium-solubilizing microbes (e.g., Rhizobium and Penicillium) may effectively solubilize potassium to assist Cd uptake by C. grandiflora. This study provides a new plant resource for Cd phytoextraction and improves our understanding of rhizosphere-associated mechanisms of plant adaptation to Cd-contaminated soil.

Fresh Phyllanthus emblica (Amla) Fruit Supplementation Enhances Milk Fatty Acid Profiles and the Antioxidant Capacities of Milk and Blood in Dairy Cows.

The objective of this study was to investigate the effect of a diet supplemented with fresh amla fruit as a natural feed additive on blood metabolic parameters, milk antioxidant capacity, and milk fatty acid (FA) proportions in lactating dairy cows. Eight ruminally cannulated mid-lactation dairy cows were used in a repeated crossover design. The first group of four cows received total mixed ration (TMR) feed without fresh amla fruit (control group). The remaining four cows sequentially supplemented fresh amla fruit (FAF) at three levels (200, 400, then 600 g/d) (treatment group) at 14-day intervals. In second period, control and treatment groups were exchanged. The first ten days were adjusted to diet adaptation for each sub-period, and the last four days for sampling milk and blood. A total of 514 metabolites were detected from FAF using UPLC-ESI-MS/MS. The five main metabolites in FAF were phenolic acids (22%), flavonoids (20%), lipids (20%), amino acids and derivatives (9%), and tannins (7%). Amla fruit supplementation reduced total saturated fatty acid and the omega-6/omega-3 ratio at 200 or 400 g/d FAF dose compared to controls. In addition, amla fruit increased unsaturated FA, such as C20:5 (Eicosapentaenoic acid, EPA) and C22:6 (docosahexaenoic acid, DHA), and branched-chain FA in a dose-dependent manner at 200 or 400 g/d compared to controls. In addition, amla fruit increased the antioxidant capacity biomarkers in the blood, such as superoxide dismutase (SOD) and albumin; this confirms that amla fruit is an excellent antioxidant, inhibiting reactive oxygen species' (ROS) metabolism, and can thereby protect cells from oxidative stress. Moreover, the most remarkable improvement of ferric reducing-antioxidant power (FRAP) and total antioxidant capacity (TAC) in milk was recorded at 400 g/d FAF doses compared to controls. Therefore, fresh amla fruit doses for lactating cows at 400 g/d on an as-fed basis can be used as an alternative additive feed in dairy cow diets to improve antioxidant capacity, protein efficiency, butter quality, and to produce more desirable milk fatty acid profiles for human consumption.

A new record of Ganodermatropicum (Basidiomycota, Polyporales) for Thailand and first assessment of optimum conditions for mycelia production.

In this study a new record of Ganodermatropicum is described as from Chiang Rai Province, Thailand. The fruiting body was collected on the base of a living Dipterocarpus tree. The sample is described on the basis of morphological characteristics and phylogenetic analyses, and compared with closely related taxa. Multigene phylogenetic analyses of LSU, ITS, and RPB2 highly support the placement of the G.tropicum group with isolates from China and Taiwan (Maximum likelihood 100%, Maximum parsimony 100%, and Bayesian posterior probabilities 1.00). The optimal media, pH, and temperature for mycelial growth of the G.tropicum strain KUMCC18-0046 was also investigated and is reported as: PDA, MEA, and YPD, at pH 7-8 and 25-28 °C, respectively. This is the first report on the successful growing conditions for mycelial production, but unfortunately fruiting could not be achieved.

Rubber seed oil and flaxseed oil supplementation on serum fatty acid profile, oxidation stability of serum and milk, and immune function of dairy cows

Objective: This study was designed to investigate the effect of diet supplementation with rubber seed oil and flaxseed oil on serum fatty acids profile, oxidation stability of serum and milk, and immune function of dairy cows. Methods: Forty-eight mid-lactation Holstein dairy cows were randomly assigned to one of four treatments for 8wk, including basal diet (CON) or the basal diet supplemented with 4% rubber seed oil (RO), 4% flaxseed oil (FO) or 2% rubber seed oil plus 2% flaxseed oil (RFO) on a DM basis. Results: Compared with CON, all the oil groups increased the levels of trans-11 C18:1 (vaccenic acid, VA), cis-9, trans-11 C18:2 (conjugated linoleic acid, CLA) and C18:3 (α-linolenic acid, ALA) in serum. Both the activity of glutathione peroxidase and catalase in serum and milk in oil groups were decreased, which were negatively correlated with the levels of cis-9, trans-11 CLA and ALA. The concentrations of proinflammatory factors (TNF-α and INF-γ) in serum of oil groups were lower than that from the CON cows. Conclusion: These results indicate that diet supplementation with rubber seed oil or flaxseed oil could alter serum fatty acid profile and enhance the immune function of dairy cows. However, the negative effect on milk oxidation stability should be considered when feeding these n-3 PUFA-enriched oils in dairy production.