MYB gene family plays crucial roles in growth and development, hormone signal transduction and metabolite regulation in plants. In this study, the identification and characterization of R2R3-MYBs and exploration on MYB34 were investigated in Isatis indigotica. The results revealed that there were 105 IiR2R3-MYB members, distributed across seven chromosomes. They were classified into 25 subfamilies, showing evolutionary and functional similarities to Arabidopsis thaliana. Moreover, 32 IiR2R3-MYBs involved in secondary metabolism pathways, whose expression patterns in different organs and stages were further studied using qRT-PCR. Furthermore, the functions of IiMYB34 were investigated. When IiMYB34 was introduced in Isatis indigotica, a notable decrease was observed both in the content of glucosinolates (GSLs) and the expression levels of IiCYP79F1 and IiCYP83A1 involved in aliphatic GSL biosynthesis, and IiCYP79B2, IiCYP83B1 and IiSOT16 involved in indolic GSL biosynthesis. Besides, over-expression of IiMYB34 in Nicotiana benthamiana resulted in an increased content of flavonoids and anthocyanins, and expression level of related enzyme genes. These findings contributed to the exploration on the regulatory mechanisms of MYBs involved in GSL biosynthesis and provided the potential molecular breeding strategies for Isatis indigotica.

Heavy metal pollution has resulted in severe environmental issues. The growth and development of crops in cadmium (Cd)-contaminated soil are inhibited, and the edible parts often exceed Cd safety standards, posing significant risks to human health. Therefore, it is crucial to minimize the Cd level in cereals. Microbial fermentation has been shown to be an effective strategy for removing Cd from these contaminated cereals. In this study, raw rice grains with a Cd level of 1.80 mg kg-1 and mung beans with a Cd level of 0.90 mg kg-1 were used as experimental materials. The single-factor and response surface optimization experiments were conducted to investigate three mixed lactobacillus (mixed-LAB) fermentation on rheological and sensory properties of rice flour. The optimized conditions were determined as follows: 9 % volume of mixed-LAB fermentation, the fermentation time of 29 h,the liquid-solid ratio of 5:1, and the fermentation temperature of 34 degrees C. When applied to Cd-contaminated mung bean flour (0.90 mg kg-1 Cd), the fermentation process reduced the Cd level to 0.11 mg kg-1, corresponding to a removal rate of 88 %. After fermentation, the starch purity of the mung bean flour reached approximately 94 %, and the resulting starch exhibited enhanced coagulation ability and superior toughness. Our findings demonstrate that mixed-LAB fermentation is an effective technique for removing Cd from agricultural products contaminated with Cd levels exceeding safety standards. However, it increased starch purity while causing protein loss.

Gibberella root rot (GRR), caused by Fusarium graminearum, is one of the major threats to maize production. However, the mechanism underlying maize's response to GRR is not fully understood. Multi-omics study incorporating metabolomics reveals insights into maize-pathogen interactions. Using metabolomics and mass spectrometry imaging (MSI), maize inbred lines with GRR resistance (W438) and susceptibility (335M) were deployed to characterize specific metabolites associated with GRR. Analysis of significantly altered metabolites suggested that glycerophospholipid metabolism was highly associated with GRR resistance or susceptibility. Furthermore, the distinct accumulation of lysophosphatidylethanolamine (lysoPE) and lysophosphatidylcholine (lysoPC) from glycerophospholipid metabolism, along with the significant up-regulation of phospholipase (PLA) gene in the susceptible line, suggested that high levels of lysoPC and lysoPE contributed to GRR susceptibility. Meanwhile, genes encoding lysophospholipase (LPLA), the detoxification enzymes of lysoPC, were significantly activated in both genotypes. However, the significantly higher expression of LPLAs in the resistant line corresponded to a significant increase in the content of non-toxic sn-glycero-3-phosphocholine, whereas this increase was not observed in the susceptible line. MSI analysis revealed the involvement of other potential phospholipids in GRR susceptibility. Taken together, maintaining an appropriate concentration of lysophospholipids is crucial for their role in the signaling pathway that triggers GRR resistance without causing damage to maize roots.

Polyploidization is a rapid breeding strategy for producing new varieties with superior agronomic traits. Kenaf (Hibiscus cannabinus L.), an important fiber crop, exhibits high adaptability to diverse stress conditions. However, comprehensive studies on polyploid induction, screening, and genetic identification in kenaf remain unreported. This study first established an optimal tetraploid induction system for diploid kenaf seeds using colchicine. The results showed that a 4-h treatment with 0.3% colchicine yielded the highest tetraploid induction rate of 37.59%. Compared with diploids, tetraploid plants displayed distinct phenotypic and physiological characteristics: dwarfism with shortened internodal distance, increased stem thickness, larger and thicker leaves with deeper green color and serration, as well as enlarged flowers, capsules, and seeds. Physiologically, tetraploid leaves featured increased chloroplast numbers in guard cells, reduced stomatal density, and larger pollen grains, elevated chlorophyll content. Further analyses revealed that tetraploid kenaf had elevated contents of various trace elements, enhanced photosynthetic efficiency, prolonged growth duration, and superior agronomic traits with higher biomass (54.54% higher fresh weight, 79.17% higher dry weight). These findings confirm the effectiveness of colchicine-induced polyploidization in kenaf, and the obtained tetraploid germplasm provides valuable resources for accelerating the breeding of elite kenaf varieties with improved yield and quality.

Anthropogenically caused nitrogen (N) enrichment may stimulate both photosynthetic carbon (C) fixation and infection of foliar pathogens. However, the interactive effects of N input and foliar fungal pathogens on the ecosystem C cycling are poorly understood. Using a 6‐year field experiment with N input and fungicide application in a Tibetan alpine meadow, we examined how N enrichment and foliar fungal pathogens influence ecosystem C sequestration independently and in combination, possibly resulting in interactions between N enrichment and fungal pathogens. Nitrogen input increased the gross ecosystem productivity (GEP) and ecosystem respiration (ER) through increasing plant biomass and foliar N content but did not affect net ecosystem productivity (NEP). Fungicide application increased GEP and NEP by relieving foliar pathogen infection but did not affect ER, resulting in net increased ecosystem C sequestration. However, no significant interactive effects between N input and fungicide application were detected. Synthesis . These results indicate that foliar fungal pathogens are critical biotic factors influencing ecosystem C sequestration in alpine ecosystems independent of N input. This study emphasizes the important role of biotic factors in regulating ecosystem functions.

Long-term cadmium (Cd) exposure inhibits plant growth and development, reduces crop yield and quality, and threatens food security. Exploring the Cd tolerance mechanisms and safe production of crops in Cd-contaminated environment has become a worldwide concern. In this study, mung bean (Vigna radiata L.) cultivar Sulu (SL) and its three mutant lines (20#, 09#, and 06#) were used to compare the difference in Cd absorption, accumulation, and tolerance through pot and field experiments. 20#, 09#, and 06# are Cd-tolerant germplasms of mung bean but exist in different Cd tolerance mechanisms, 20# exhibited the lowest Cd absorption capacity, 09# possessed lower Cd translocation capacity, while 06# accumulated more Cd in protoplasts. Mung bean germplasms with higher Cd tolerance generally showed lower absorption capacity and intracellular accumulation of Cd. Besides, Cd accumulation in mung bean seeds is mainly depended on the absorption and translocation of Cd in roots and the Cd concentration in leaves, exogenous Mn supply inhibited the Cd2+ net influx of roots and Cd accumulation in seeds, this trend was more pronounced in mung bean germplasms with higher Cd accumulation and absorption. Moreover, we characterized a Cd transporter gene VrNramp5, which was differentially expressed in different mung bean lines, overexpression of VrNramp5 increased Cd accumulation and was accompanied by Cd-sensitive phenotype in transgenic mung bean seedlings, and the Cd concentration of mung bean was significantly positively correlated with the expression levels of VrNramp5. Taken together, our findings demonstrated that different Cd tolerance mechanisms exist in mung bean. 20# is the new Cd-tolerant germplasm with low Cd absorption capacity and Cd accumulation in seeds, and has great potential for the safe production of mung bean in Cd-contaminated soils and the breeding of low Cd accumulation crop cultivars.

Plant reproductive phenology is sensitive to climate change and has great implications for plant reproduction, community structure and ecosystem functions. Shifts in reproductive phenology under warmer temperatures have been widely studied, but how other global change factors, such as nitrogen enrichment and altered precipitation, interact with warming to influence phenology remains poorly understood. We conducted a field experiment in a Tibetan alpine meadow to examine the effects of warming, nitrogen addition, precipitation reduction and their interaction on plant reproductive phenology in 2017 and 2021. We found that warming interacted with precipitation reduction to affect reproductive phenology, independent of nitrogen addition. Specifically, warming led to an advance in flowering (3.5 days) and fruiting onset (3.8 days), but precipitation reduction offset this effect. Warming also extended the duration of flowering and reproduction but only when interacting with precipitation reduction. Nitrogen addition delayed the onset of flowering (2.1 days) and fruiting (1.8 days). Moreover, the effects of warming depended on the phenological niche of each species as well as its pollination mode. Early-flowering species advanced more in flowering onset than late-flowering species. The duration of flowering and reproduction of wind-pollinated species was prolonged while that of insect-pollinated species was shortened by warming. Our study highlights the necessity of considering the interaction of multiple factors in predicting phenological responses under global change and suggests that plant life-history traits should be taken into account in future studies.

Our understanding of biodiversity patterns comes primarily from described species. Here, we analyze how known biodiversity has increased across living organisms. Past research suggested that the number of new species per year peaked near 1900 and that only ~2 million species exist. We find that overall rates of species descriptions have recently accelerated, with the largest numbers of new species per year all in the past ~20 years (2000 to 2020). The largest groups grew the most quickly during this period, including animals, arthropods, insects, and beetles. However, long-term trends in rates of species descriptions were often unrelated to recent rates and current richness. For example, rates for fungi have recently increased, whereas rates for insects have not. Extrapolating these rates of species descriptions into the future requires considerable caution. Nevertheless, some intriguing patterns are suggested, such as unexpectedly high projected species numbers of plants, fungi, arachnids, malacostracan crustaceans, ray-finned fishes, and amphibians.

The aim of this study was to develop an efficient strategy for enhancing H2 production in the single-chamber microbial electrolysis cell (MEC) using food waste leachate as a substrate. Different pH (8.5, 9.5, 10.5, and 11.2), applied voltage (0.8, 1.2, 1.5, 1.8, 2.0, 2.2, 2.3, and 2.4 V) and negative pressure control (-50 kPa) were tested in the single-chamber MEC. Suitable pH adjustment could greatly promote electricity generation and H2 production rather than negative pressure control. Under pH of 11.5 and 2.4 V, the maximum current density reached 121.9 f 10.9 A/m3 with an average H2 concentration of 91.9 f 3.2% in a 1.2-L single-chamber MEC within 30 continuous cycles of operation (-607 h), which was constructed with carbon brushes as the anode and stainless steel brushes as the cathode. The maximum H2 production rate reached 853.2 f 70.3 L/m3 center dot d with an H2 yield of 26.3 mmol center dot H2/g center dot COD. The COD removal of 68.3 f 6.8% and three-dimensional excitation-emission matrix spectra of the effluent in the MEC within 21 f 3h indicated efficient organics degradation in the leachate. Our results should provide a promising way to enhance the H2 production of MEC during leachate treatment.

Soil acidification often suppresses microbial growth and activities, resulting in a negative impact on soil organic carbon (C) decomposition. While the detrimental effects of acidification on soil and plant properties have been extensively studied, less attention has been paid on the shifts in soil microbial communities and their influences of the decomposition of organic C with different chemical complexities. Taking advantage of an acid addition experiment in a Tibetan alpine meadow, here we examined the response of soil microbial communities to soil acidification and microbial effect on the decomposition of organic C with different chemical complexities (i.e., glucose and lignin, representing labile and recalcitrant C respectively). We found that soil acidification had no impact on microbial respiration and microbial abundance even though it decreased bacterial diversity significantly. Soil acidification increased the relative abundance of some microbial taxa, like Alphaproteobacteria and Acidobacteriia in bacteria increased by 36 %, 284 %, and Eurotiomycetes, Sordariomycetes and Leotiomycetes in fungi increased by 145 %, 279 % and 12.7-fold, but decreased the relative abundance of Acidimicrobiia by 33 % in highest acid addition treatment. Changes in microbial communities (bacterial and fungal community composition, the diversity of bacterial community and the ratio of fungi to bacteria) are significantly related to the decomposition of glucose and lignin. More specifically, soil acidification decreased the decomposition of glucose but increased the decomposition of lignin, indicating a trade-off between the decomposition of labile and recalcitrant soil organic C under soil acidification. Overall, shifts in microbial communities under soil acidification might be accompanied by an increased ability to break down more recalcitrant C. This trade-off between the decomposition of labile and recalcitrant C may change soil C quality under future acid deposition scenarios.

The comprehensive evaluation of crop germplasm serves to scientifically and objectively assess the quality of different genetic accessions against certain standards. Here, we propose an optimized approach to enhance the result’s stability when assessing salt tolerance in crop germplasm. This protocol was applied to a case study involving 249 tomato genotypes, systematically refining the processes involved in constructing an evaluation index system, data preprocessing, statistical method selection, and weight calculation. The optimization process reduced the system variance of salt tolerance evaluation results and achieved an 85.42% concordance with a classical approach, across a tomato population covering 241 genotypes, suggesting the improved stability and high accuracy of the optimized protocol. Moreover, an 83.82% consistency rate between pre- and post-optimization results also suggested the high accuracy of the optimized protocol. The enhanced stability was further confirmed by a secondary validation on a subpopulation (covering 39 genotypes), which demonstrated a consistency rate of 83.87% between the two populations. The study identified 8.43% of the evaluated germplasm as salt-tolerant accessions, providing valuable parental materials for breeding programs. The findings underscore the potential of our protocol for the precise identification of stress-resistant germplasm, contributing to the development of stress-tolerant crop varieties.

In cereal grains, starch is synthesized by the concerted actions of multiple enzymes on the surface of starch granules within the amyloplast. However, little is known about how starch-synthesizing enzymes access starch granules, especially for amylopectin biosynthesis. Here, we show that the rice (Oryza sativa) floury endosperm9 (flo9) mutant is defective in amylopectin biosynthesis, leading to grains exhibiting a floury endosperm with a hollow core. Molecular cloning revealed that FLO9 encodes a plant-specific protein homologous to Arabidopsis (Arabidopsis thaliana) LIKE EARLY STARVATION1 (LESV). Unlike Arabidopsis LESV, which is involved in starch metabolism in leaves, OsLESV is required for starch granule initiation in the endosperm. OsLESV can directly bind to starch by its C-terminal tryptophan (Trp)-rich region. Cellular and biochemical evidence suggests that OsLESV interacts with the starch-binding protein FLO6, and loss-of-function mutations of either gene impair ISOAMYLASE1 (ISA1) targeting to starch granules. Genetically, OsLESV acts synergistically with FLO6 to regulate starch biosynthesis and endosperm development. Together, our results identify OsLESV-FLO6 as a non-enzymatic molecular module responsible for ISA1 localization on starch granules, and present a target gene for use in biotechnology to control starch content and composition in rice endosperm.

Drought stress, which often occurs repeatedly across the world, can cause multiple and long-term effects on plant growth. However, the repeated drought–rewatering effects on plant growth remain uncertain. This study was conducted to determine the effects of drought–rewatering cycles on aboveground growth and explore the underlying mechanisms. Perennial ryegrass plants were subjected to three watering regimes: well-watered control (W), two cycles of drought–rewatering (D2R), and one cycle of drought–rewatering (D1R). The results indicated that the D2R treatment increased the tiller number by 40.9% and accumulated 28.3% more aboveground biomass compared with W; whereas the D1R treatment reduced the tiller number by 23.9% and biomass by 42.2% compared to the W treatment. A time-course transcriptome analysis was performed using crown tissues obtained from plants under D2R and W treatments at 14, 17, 30, and 33 days (d). A total number of 2272 differentially expressed genes (DEGs) were identified. In addition, an in-depth weighted gene co-expression network analysis (WGCNA) was carried out to investigate the relationship between RNA-seq data and tiller number. The results indicated that DEGs were enriched in photosynthesis-related pathways and were further supported by chlorophyll content measurements. Moreover, tiller-development-related hub genes were identified in the D2R treatment, including F-box/LRR-repeat MAX2 homolog (D3), homeobox-leucine zipper protein HOX12-like (HOX12), and putative laccase-17 (LAC17). The consistency of RNA-seq and qRT-PCR data were validated by high Pearson’s correlation coefficients ranging from 0.899 to 0.998. This study can provide a new irrigation management strategy that might increase plant biomass with less water consumption. In addition, candidate photosynthesis and hub genes in regulating tiller growth may provide new insights for drought-resistant breeding.

This study aimed to propose a novel approach for simultaneous CO2 abatement and energy storage in microbial electrolysis cells (MECs). The methane (CH4) production from CO2 was achieved in a graphite granule–filled cathodic compartment of an MEC separated by a modified nylon cloth. Using the modified nylon cloth in MEC significantly reduced membrane internal resistance compared with the control where a commercial proton exchange membrane (PEM) was used (PEM: 1746 ± 80 TΩ/cm; nylon cloth: 251 ± 8 TΩ/cm). Consequently, CH4 production realized 72.9 ± 24.4mL/(L ∙ d) with an average energy efficiency of 121 ± 39% compared with halted electromethanogenesis in PEM-equipped MEC. Metagenomics affirmed the predominance of hydrogenotrophic methanogens Methanocorpusculum and Methanobacterium. Moreover, H2-mediated methanogenesis contributed significantly to electromethanogenesis in nylon-MEC. This study demonstrated that the bioelectrochemical conversion of CO2 into CH4 in a nylon-MEC could be viable for CO2 sequestration combined with energy storage (power to gas).

Nanobubble water (NW) has been reported to enhance anaerobic digestion (AD), but its influence on the metabolic pathways of microorganisms remains unclear. In this study, the specific methane yields of rice straw in the CO2NW and O2NW treatments increased by 6.9% and 18.3%, respectively. The electron transport system (ETS) and coenzyme F420 activities were enhanced by the addition of NW. Metagenomic analysis showed that the abundances of most enzymes in the acidification were significantly increased by both CO2NW and O2NW. Regarding methanogenesis, CO2NW promoted the expression of genes encoding enzymes of hydrogenotrophic methanogenesis, while O2NW stimulated both the acetoclastic and hydrogenotrophic methanogenesis. With the addition of O2NW, the expressions of modules related to the tricarboxylic acid (TCA) cycle and oxidative phosphorylation were enhanced, resulting in increased ATP production. This study provided fundamental evidence of the metabolic pathways of microorganisms mediated by NW at each stage of AD.

Nanobubble technology was used to enhance anaerobic digestion (AD) of thermal-hydrolysis pre-treated sewage sludge for bioenergy recovery. The prepared air, CO2, and H2 nanobubble solutions, with concentrations of 9.88-10.2 x 107 bubbles/mL, remained stable for at least 7 days. After adding them into AD reactors, significantly higher CH4 production (37.1 %) was observed for the CO2 nanobubble treatment, followed by air (25.6 %) and H2 (14.5 %) nanobubble treatments, compared to the control group. CO2 nanobubble treatment performed the best in improving acidogenesis/acetogenesis, resulting in significantly higher volatile fatty acid generation during the initial 3-4 days. A comparison of reactors supersaturated and non-saturated with oxygen has demonstrated most of the biogas uplift observed to result from the nanobubbles rather than from initial oxygen soluble levels, demonstrating the crucial role of nanobubbles in upgrading AD. This study demonstrates, for the first time, that nanobubbles can provide additional benefits when combined with stablished sludge pre-treatment technologies.

Cadmium (Cd) is a highly toxic non-essential element, which requires the transporters of essential and beneficial elements to enter the plant, and poses threat to plant growth and development. However, the mechanism of Cd uptake and accumulation in mungbean is limited. Here, we reported a Cd transporter VrNramp5 in mungbean, and its functional roles in response to Cd toxicity were conducted. The expression of VrNramp5 was downregulated by Cd toxicity. VrNramp5 localized at plasma membrane based on subcellular localization analysis in epidermal cells of Nicotiana benthamiana. Heterologous expression of VrNramp5 in Arabidopsis thaliana promoted Cd accumulation, displayed the Cd sensitive phenotype including decreased root elongation and fresh weight, and VrNramp5 could diminish the Cd tolerance phenotype of AtNramp1-deficient mutant (atnramp1). Non-invasive micro-test showed that VrNramp5-overexpressing lines possessed higher Cd absorption capacity in root tips. Moreover, the Cd fluorescence probe staining revealed that more Cd accumulated in the leaf protoplasts of VrNramp5-overexpressing Arabidopsis. Those were consistent with the plants grown in the absence or presence of Cd (10 mg kg -1 or 20 mg kg -1) in soil. Taken together, VrNramp5 is responsible for plant Cd tolerance via regulating the Cd absorption capacity of roots and altering the intracellular distribution of Cd. Our findings provide a theoretical basis for further exploring the mechanism of Cd tolerance and breeding variety of mungbean with low Cd accumulation.

This study explored the efficiency of CO2-, N2- and H2-NBW application in anaerobic digestion (AD) of rice straw, focus on methanogenic performance and metabolic pathway, and revealed the underlying mechanisms. The results showed that NBW addition enhanced total methane production by 4.22% to 7.79% compared to the control group. Mechanism investigations revealed that NBW increased the degradation of cellulose and hemicellulose by breaking the lignin-coated structure, leading to higher soluble carbohydrates (6.27%-11.13%), α-glucosidase activities (12.32%-23.72%), VFAs (4.39%-24.50%), and cumulative H2 yield (74-94 times). In addition, the modified Gompertz model and the first-order kinetic analysis indicated that NBW could improve the reaction rates of AD and H2 production stages, with CO2-NBW demonstrating the most prominent effect. Based on the analysis, it can be concluded that NBW mainly promotes hydrolytic acidification rather than methane production. The results suggest that NBW is beneficial in enhancing the AD process of cellulosic biomass.

This study explored the efficiency of CO2-, N2- and H2-nanobubble water (NBW) application in anaerobic digestion (AD) of rice straw (RS) and revealed the underlying mechanisms. The results showed that NBW addition enhanced total methane production by 4.22 to 7.79% compared to the control group. Mechanism investigations revealed that NBW increased the degradation of RS cellulose and hemicellulose by breaking the lignincoated structure, leading to higher soluble carbohydrates (106.27% -111.13%), αglucosidase activities (6.27%-11.13%), VFAs (4.39%-24.50%), and cumulative H2 yield (74-94 times). In addition, kinetic analysis indicated that NBW can improve the reaction rates of AD and H2 production stages, with CO2-NBW demonstrating the most prominent effect. Based on the analysis, it can be concluded that NBW mainly promotes hydrolytic acidification rather than methane production. The results suggest that NBW is beneficial in enhancing the AD process of cellulosic biomass devoid of any chemical additives and requiring minimal energy consumption.

Broad diversity of flowers in Fabaceae provides a good system to investigate development and evolution of floral symmetry in higher plants. Many studies have demonstrated a conserved mechanism controlling development of zygomorphic flower during last decades. However, the molecular basis of how asymmetric flower established is largely unknown. In this study, we characterized mutants named keeled wings (kw) in mungbean (Vigna radiata L.), which is a legume species with asymmetric flowers. Compared to those in the wild type plants, the lateral petals were ventralized in the kw mutants. Map-based cloning showed that KW was VrCYC3 gene in mungbean, the ortholog of Lotus japonicus CYC3 (LjCYC3) and Pisum sativum CYC3 (PsCYC3). In addition, another two CYC-like genes named VrCYC1 and VrCYC2 were identified from mungbean genome. The three CYC-like genes displayed distinct expression patterns in dorsal, lateral and ventral petals. It was found that VrCYC3 was located in nucleus. Further analysis showed that VrCYC3 had transcription activity and could interact with VrCYC1 and VrCYC2 in yeast cell. Moreover, the deletion of two amino acid residues in the R domain of VrCYC3 protein could decrease its interaction with VrCYC1 and VrCYC2 proteins. Our results suggest that LjCYC3/VrCYC3 orthologs play conserved roles determining the lateral petal shape and identity of zygomorphic flower as well as asymmetric flower in Papilionoideae.