An L-type lectin receptor-like kinase promotes starch accumulation during rice pollen maturation.

Starch accumulation is key for the maturity of rice pollen grains; however, the regulatory mechanism underlying this process remains unknown. Here, we have isolated a male-sterile rice mutant, abnormal pollen 1 (ap1), which produces nonviable pollen grains with defective starch accumulation. Functional analysis revealed that AP1 encodes an active L-type lectin receptor-like kinase (L-LecRLK). AP1 is localized to the plasma membrane and its transcript is highly accumulated in pollen during the starch synthesis phase. RNA-seq and phosphoproteomic analysis revealed that the expression/phosphorylation levels of numerous genes/proteins involved in starch and sucrose metabolism pathway were significantly altered in the mutant pollen, including a known rice UDP-glucose pyrophosphorylase (OsUGP2). We further found that AP1 physically interacts with OsUGP2 to elevate its enzymatic activity, likely through targeted phosphorylation. These findings revealed a novel role of L-LecRLK in controlling pollen maturity via modulating sucrose and starch metabolism.

Diversity and composition of microbial communities in Jinsha earthen site under different degree of deterioration.

Earthen sites are the important cultural heritage that carriers of human civilization and contains abundant history information. Microorganisms are one of important factors causing the deterioration of cultural heritage. However, little attention has been paid to the role of biological factors on the deterioration of earthen sites at present. In this study, microbial communities of Jinsha earthen site soils with different deterioration types and degrees as well as related to environmental factors were analyzed. The results showed that the concentrations of Mg2+ and SO42- were higher in the severe deterioration degree soils than in the minor deterioration degree soils. The Chao1 richness and Shannon diversity indices of bacteria in different type deterioration were higher in the summer than in the winter; the Chao1 and Shannon indices of fungi were lower in the summer. The differences in bacterial and fungal communities were associated with differences in Na+, K+, Mg2+ and Ca2+ contents. Based on both the relative abundances in amplicon sequencing and isolated strains, the bacterial phyla Actinobacteria, Firmicutes and Proteobacteria, and the Ascomycota genera Aspergillus, Cladosporium and Penicillium were common in all soils. The OTUs enriched in the severe deterioration degree soils were mostly assigned to Actinobacteria and Proteobacteria, whereas the Firmicutes OTUs differentially abundant in the severe deterioration degree were all depleted. All bacterial isolates produced alkali, implying that the deterioration on Jinsha earthen site may be accelerated through alkali production. The fungal isolates included both alkali and acid producing strains. The fungi with strong ability to produce acid were mainly from the severe deterioration degree samples and were likely to contribute to the deterioration. Taken together, the interaction between soil microbial communities and environment may affect the soil deterioration, accelerate the deterioration process and threaten the long-term preservation of Jinsha earthen site.

Bacterial community in the buckwheat rhizosphere responds more sensitively to single microplastics in lead-contaminated soil compared to the arbuscular mycorrhizal fungi community.

Soil pollution by microplastics (MPs), defined as plastic particles <5 mm, and heavy metals is a significant environmental issue. However, studies on the co-contamination effects of MPs and heavy metals on buckwheat rhizosphere microorganisms, especially on the arbuscular mycorrhizal fungi (AMF) community, are limited. We introduced low (0.01 g kg-1) and high doses of lead (Pb) (2 g kg-1) along with polyethylene (PE) and polylactic acid (PLA) MPs, both individually and in combination, into soil and assessed soil properties, buckwheat growth, and rhizosphere bacterial and AMF communities in a 40-day pot experiment. Notable alterations were observed in soil properties such as pH, alkaline hydrolyzable nitrogen (AN), and the available Pb (APb). High-dose Pb combined with PLA-MPs hindered buckwheat growth. Compared to the control, bacterial Chao1 richness and Shannon diversity were lower in the high dose Pb with PLA treatment, and differentially abundant bacteria were mainly detected in the high Pb dose treatments. Variations in bacterial communities correlated with APb, pH and AN. Overall, the AMF community composition remained largely consistent across all treatments. This phenomenon may be due to fungi having lower nutritional demands than bacteria. Stochastic processes played a relatively important role in the assembly of both bacterial and AMF communities. In summary, MPs appeared to amplify both the positive and negative effects of high Pb doses on the buckwheat rhizosphere bacteria.

Insights into antibiotic and heavy metal resistance interactions in Escherichia coli isolated from livestock manure and fertilized soil.

Heavy metal and antibiotic-resistant bacteria from livestock feces are ecological and public health problems. However, the distribution and relationships of antibiotic resistance genes (ARGs), heavy metal resistance genes (HMRGs), and virulence factors (VFs) and their transmission mechanisms remain unclear. Therefore, we investigated the resistance of Escherichia coli, the prevalence of its ARGs, HMRGs, and VFs, and their transmission mechanisms in livestock fresh feces (FF), composted feces (CF), and fertilized soil (FS). In total, 99.54% (n = 221) and 91.44% (n = 203) of E. coli were resistant to at least one antibiotic and one heavy metal, respectively. Additionally, 72.52% (n = 161) were multi-drug resistant (MDR), of which Cu-resistant E. coli accounted for 72.67% (117/161). More than 99.34% (88/89) of E. coli carried multidrug ARGs, VFs, and the Cu resistance genes cueO and cusABCRFS. The Cu resistance genes cueO and cusABCRFS were mainly located on chromosomes, and cueO and cusF were positively associated with HMRGs, ARGs, and VFs. The Cu resistance genes pcoABCDRS were located on the plasmid pLKYL-P02 flanked by ARGs in PF18C from FF group and on chromosomes flanked by HMRGs in SAXZ1-1 from FS group. These results improved our understanding of bacterial multidrug and heavy metal resistance in the environment.

Bacterial community drives soil organic carbon transformation in vanadium titanium magnetite tailings through remediation using Pongamia pinnata.

With continuous mine exploitation, regional ecosystems have been damaged, resulting in a decline in the carbon sink capacity of mining areas. There is a global shortage of effective soil ecological restoration techniques for mining areas, especially for vanadium (V) and titanium (Ti) magnetite tailings, and the impact of phytoremediation techniques on the soil carbon cycle remains unclear. Therefore, this study aimed to explore the effects of long-term Pongamia pinnata remediation on soil organic carbon transformation of V-Ti magnetite tailing to reveal the bacterial community driving mechanism. In this study, it was found that four soil active organic carbon components (ROC, POC, DOC, and MBC) and three carbon transformation related enzymes (S-CL, S-SC, and S-PPO) in vanadium titanium magnetite tailings significantly (P < 0.05) increased with P. pinnata remediation. The abundance of carbon transformation functional genes such as carbon degradation, carbon fixation, and methane oxidation were also significantly (P < 0.05) enriched. The network nodes, links, and modularity of the microbial community, carbon components, and carbon transformation genes were enhanced, indicating stronger connections among the soil microbes, carbon components, and carbon transformation functional genes. Structural equation model (SEM) analysis revealed that the bacterial communities indirectly affected the soil organic carbon fraction and enzyme activity to regulate the soil total organic carbon after P. pinnata remediation. The soil active organic carbon fraction and free light fraction carbon also directly regulated the soil carbon and nitrogen ratio by directly affecting the soil total organic carbon content. These results provide a theoretical reference for the use of phytoremediation to drive soil carbon transformation for carbon sequestration enhancement through the remediation of degraded ecosystems in mining areas.

Grass-specific ABERRANT MICROSPORE DEVELOPMENT 1 is required for maintaining pollen fertility in rice.

Pollen development includes a series of biological events that require precise gene regulation. Although several transcription factors (TFs) have been shown to play roles in maintaining pollen fertility, the major regulatory networks underlying tapetum development and pollen wall formation are largely unknown. Herein, we report that ABERRANT MICROSPORE DEVELOPMENT1 (AMD1), a protein annotated previously as unknown protein, is required for tapetum development and pollen exine patterning in rice (Oryza sativa L.). AMD1 encodes a grass-specific protein exhibiting transactivation activity in the nucleus and is spatiotemporally expressed in the tapetum and microspores during pollen development. Further biochemical assays indicate that AMD1 directly activates the transcription of DEFECTIVE POLLEN WALL (DPW) and POLYKETIDE SYNTHASE2 (OsPKS2), which are both implicated in sporopollenin biosynthesis during exine formation. Additionally, AMD1 directly interacts with TAPETUM DEGENERATION RETARDATION (TDR), a key TF involved in the regulation of tapetum degradation and exine formation. Taken together, we demonstrate that AMD1 is an important regulatory component involved in the TDR-mediated regulatory pathway to regulate sporopollenin biosynthesis, tapetum degradation, and exine formation for pollen development. Our work provides insights into the regulatory network of rice sexual reproduction and a useful target for genetic engineering of new male-sterile lines for hybrid rice breeding.

Simultaneous editing of three homoeologues of TaCIPK14 confers broad-spectrum resistance to stripe rust in wheat.

Wheat stripe rust caused by the fungus Puccinia striiformis f. sp. tritici (Pst) is one of the most destructive wheat diseases resulting in significant losses to wheat production worldwide. The development of disease-resistant varieties is the most economical and effective measure to control diseases. Altering the susceptibility genes that promote pathogen compatibility via CRISPR/Cas9-mediated gene editing technology has become a new strategy for developing disease-resistant wheat varieties. Calcineurin B-like protein (CBL)-interacting protein kinases (CIPKs) has been demonstrated to be involved in defence responses during plant-pathogen interactions. However, whether wheat CIPK functions as susceptibility factor is still unclear. Here, we isolated a CIPK homoeologue gene TaCIPK14 from wheat. Knockdown of TaCIPK14 significantly increased wheat resistance to Pst, whereas overexpression of TaCIPK14 resulted in enhanced wheat susceptibility to Pst by decreasing different aspects of the defence response, including accumulation of ROS and expression of pathogenesis-relative genes. We generated wheat Tacipk14 mutant plants by simultaneous modification of the three homoeologues of wheat TaCIPK14 via CRISPR/Cas9 technology. The Tacipk14 mutant lines expressed race-nonspecific (RNS) broad-spectrum resistance (BSR) to Pst. Moreover, no significant difference was found in agronomic yield traits between Tacipk14 mutant plants and Fielder control plants under greenhouse and field conditions. These results demonstrate that TaCIPK14 acts as an important susceptibility factor in wheat response to Pst, and knockout of TaCIPK14 represents a powerful strategy for generating new disease-resistant wheat varieties with BSR to Pst.

SWOLLEN TAPETUM AND STERILITY 1 is required for tapetum degeneration and pollen wall formation in rice.

The pollen wall is important for protecting the male gametophyte and for fertilization. The lipid components of the pollen wall are mainly synthesized and transported from the sporophytic tapetum. Although several factors related to lipid biosynthesis have been characterized, the molecular mechanisms underlying lipid biosynthesis during pollen development in rice (Oryza sativa L.) remain elusive. Here, we showed that mutation in the SWOLLEN TAPETUM AND STERILITY 1 (STS1) gene causes delayed tapetum degradation and aborted pollen wall formation in rice. STS1 encodes an endoplasmic reticulum (ER)-localized protein that contains domain of unknown function (DUF) 726 and exhibits lipase activity. Lipidomic and transcriptomic analyses showed that STS1 is involved in anther lipid homeostasis. Moreover, STS1 interacts with Polyketide Synthase 2 (OsPKS2) and Acyl-CoA Synthetase 12 (OsACOS12), two enzymes crucial in lipidic sporopollenin biosynthesis in pollen wall formation, suggesting a potentially lipidic metabolon for sporopollenin biosynthesis in rice. Collectively, our results indicate that STS1 is an important factor for lipid biosynthesis in reproduction, providing a target for the artificial control of male fertility in hybrid rice breeding and insight into the function of DUF726-containing protein in plants.

A ubiquitin-specific protease functions in regulating cell death and immune responses in rice.

Ubiquitin-specific proteases (UBPs) process deubiquitination in eukaryotic organisms and are widely involved in plant development and responses to environmental stress. However, their role in cell death and plant immunity remains largely unknown. Here, we identified a rice lesion mimic mutant (LMM) and cloned its causative gene, LMM22. Both dysfunction and overexpression of LMM22 gave rise to the hypersensitive response-like cell death, reactive oxygen species bursts, and activated defence responses. LMM22 encodes an active UBP that is localised to the endoplasmic reticulum (ER) and displays a constitutive expression pattern in rice. LMM22 interacts with SPOTTED LEAF 35 (SPL35), a coupling of ubiquitin conjugation to ER degradation domain-containing protein that is known to participate in ubiquitination and the regulation of cell death and disease response in rice. Additional analyses suggest that LMM22 can positively regulate and stabilise the abundance of SPL35 protein likely through its deubiquitination activity. These data therefore improve our understanding of the function of UBP in rice innate immune responses by demonstrating that LMM22 functions as a critical regulator of SPL35 in cell death and disease resistance.

Chelativorans petroleitrophicus sp. nov., a paraffin oil-degrading bacterium isolated from a mixture of oil-based drill cuttings and paddy soil.

We isolated a paraffin oil-degrading bacterial strain from a mixture of oil-based drill cutting and paddy soil, and characterized the strain using a polyphasic approach. The Gram-positive, aerobic, rod-shaped and non-spore-forming strain (SCAU 2101T) grew optimally at 50 °C, pH 7.0 and 0.5 % (w/v) NaCl. Phylogenetic analysis based on 16S rRNA gene sequence indicated that the strain represented a distinct clade in the genus Chelativorans, neighbouring Chelativorans intermedius LMG 28482T (97.1 %). The genome size and DNA G+C content of the strain were 3 969 430 bp and 63.1 mol%, respectively. Whole genome based phylogenomic analyses showed that the average nucleotide identity and digital DNA-DNA hybridization values between strain SCAU 2101T and C. intermedius LMG 28482T were 77.5 and 21.2 %, respectively. The major respiratory quinone was Q-10. The dominant fatty acids were C19 : 0 cyclo ω8c (50.6 %), summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c; 22.5 %) and C18 : 0 (13.8 %). The polar lipids of the strain included phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, phosphatidylcholine and diphosphatidylglycerol. Based on the results, strain SCAU 2101T was considered to represent a novel species in the genus Chelativorans, for which the name Chelativorans petroleitrophicus sp. nov. is proposed. The type strain is SCAU 2101T (= CCTCC AB 2021125T=KCTC 92067T).

Organic Fertilizers Shape Soil Microbial Communities and Increase Soil Amino Acid Metabolites Content in a Blueberry Orchard.

The decline in soil nutrients is becoming a major concern of soil degradation. The possibility of using organic waste as a soil additive to increase nutrients and essential components is significant in soil quality protection and waste management. The aim of this study was to investigate the effects of composted spent mushroom substrate (MS), giant panda feces (PF), and cattle manure (CM) as organic fertilizers in soil microbial communities and metabolites in blueberry orchard in China, which were measured by using high-throughput sequencing and gas chromatography-mass spectrometry (GC-MS)-based metabolomics. Altogether, 45.66% of the bacterial operational taxonomic units (OTUs) and 9.08% of the fungal OTUs were detected in all treatments. Principal coordinates analysis demonstrated that the bacterial and fungal communities in MS and PF treatments were similar, whereas the communities in the not-organic fertilized control (CK) were significantly different from those in the organic fertilizer treatments. Proteobacteria, Acidobacteria, and Bacteroidetes were the dominant bacterial phyla, and Basidiomycota, Ascomycota, and Mortierellomycota the dominant fungal phyla. Redundancy analysis indicated that pH and available potassium were the main factors determining the composition of microbial communities. The fungal genera Postia, Cephalotrichum, and Thermomyces increased in organic fertilizer treatments, and likely promoted the degradation of organic fertilizers into low molecular-weight metabolites (e.g., amino acids). PCA and PLS-DA models showed that the metabolites in CK were different from those in the other three treatments, and those in CM were clearly different from those in MS and PF. Co-occurrence network analysis showed that several taxa correlated positively with amino acid contents. The results of this study provide new insights into organic waste reutilization and new directions for further studies.

Effects of environmental disinfection on microbial population and resistance genes: A case study of the microecology within a panda enclosure.

Widespread use of disinfectants raises concerns over their involvement in altering microbial communities and promoting antimicrobial resistance. This study explores the influence of disinfection protocols on microbial populations and resistance genes within an isolated enclosure environment and in the gut of giant pandas (GPs) held within. Samples of panda feces, air conditioning ducts, soil and bamboo were collected before and after disinfection. High-throughput sequencing characterized the microbial flora of GP gut and environmental microbes inside the artificial habitat. Microbial cultures showed that Escherichia coli (34.6%), Enterococcus (15.4%) and other pathogenic bacteria deposited in feces and the enclosure. Isolates exhibit a consistent resistance to disinfectant, with the greatest resistance shown to cyanuric acid, and the lowest to glutaraldehyde-dodecyl dimethyl ammonium bromide (GD-DDAB) and dodecyl dimethyl ammonium bromide (DDAB). The total number of the culturable bacteria in soil and bamboo were significantly diminished after disinfection but increased in the gut. After disinfection, the richness (Chao1 index) of environment samples increased significantly (P < 0.05), while the richness in gut decreased significantly (P < 0.05). Ten genera showed significant change in feces after disinfection. Metagenome sequencing showed that 126 types of virulence genes were present in feces before disinfection and 37 in soil. After disinfection, 110 virulence genes localized in feces and 53 in soil. Eleven virulence genes including ECP and T2SS increased in feces. A total of 182 antibiotic resistance genes (ARGs) subtypes, potentially conferring resistance to 20 classes of drugs, were detected in the soils and feces, with most belonging to efflux pump protein pathways. After disinfection, the number of resistance genes increased both in gut and soil, which suggests disinfection protocols increase the number of resistance pathways. Our study shows that the use of disinfectants helps to shape the microbial community of GPs and their habitat, and increases populations of resistant strain bacteria.

Secretory lipid transfer protein OsLTPL94 acts as a target of EAT1 and is required for rice pollen wall development.

The plant pollen wall protects the male gametophyte from various biotic and abiotic stresses. The formation of a unique pollen wall structure and elaborate exine pattern is a well-organized process, which needs coordination between reproductive cells and the neighboring somatic cells. However, molecular mechanisms underlying this process remain largely unknown. Here, we report a rice male-sterile mutant (l94) that exhibits defective pollen exine patterning and abnormal tapetal cell development. MutMap and knockout analyses demonstrated that the causal gene encodes a type-G non-specific lipid transfer protein (OsLTPL94). Histological and cellular analyses established that OsLTPL94 is strongly expressed in the developing microspores and tapetal cells, and its protein is secreted to the plasma membrane. The l94 mutation impeded the secretory ability of OsLTPL94 protein. Further in vivo and in vitro investigations supported the hypothesis that ETERNAL TAPETUM 1 (EAT1), a basic helix-loop-helix transcription factor (bHLH TF), activated OsLTPL94 expression through direct binding to the E-box motif of the OsLTPL94 promoter, which was supported by the positive correlation between the expression of EAT1 and OsLTPL94 in two independent eat1 mutants. Our findings suggest that the secretory OsLTPL94 plays a key role in the coordinated development of tapetum and microspores with the regulation of EAT1.

Changes in the taxonomic and functional structures of microbial communities during vegetable waste mixed silage fermentation.

Silage fermentation, a sustainable method of using vegetable waste resources, is a complex process driven by a variety of microorganisms. We used lettuce waste as the main raw material for silage, analyzed changes in the physicochemical characteristics and bacterial community composition of silage over a 60-day fermentation period, identified differentially abundant taxa, predicted the functional profiles of bacterial communities, and determined the associated effects on the quality of silage. The largest changes occurred during the early stages of silage fermentation. Changes in the physicochemical characteristics included a decrease in pH and an increase in the ammonia nitrogen to total nitrogen ratio and lactic acid content. The number of lactic acid bacteria (LAB) increased, while molds, yeasts, and aerobic bacteria decreased. The bacterial communities and their predicted functions on day 0 were different from those on day 7 to day 60. The relative abundances of phylum Firmicutes and genus Lactobacillus increased. Nitrite and nitrate ammonification were more prevalent after day 0. The differences in the predicted functions were associated with differences in pH and amino acid, protein, carbohydrate, NH3-N, ether extract, and crude ash contents.

Role of rhizobia in promoting non-enzymatic antioxidants to mitigate nitrogen-deficiency and nickel stresses in Pongamia pinnata.

The contribution of rhizobia in the mitigation of non-enzymatic antioxidants against nitrogen deficiency and heavy metal toxicity for legume plant is not clear. Therefore, it is hypothesized that the inoculation of rhizobia could mitigate nitrogen deficiency and nickel (Ni) stresses in P. pinnata tissues by enhancing the formation of certain non-enzymatic antioxidants. The effect of symbiotic nitrogen-fixing rhizobia on the mitigation of nitrogen-deficiency and Ni stresses in P. pinnata was evaluated by inoculating two different rhizobia, i.e., Rhizobium pisi PZHK2 and Ochrobacterium pseudogrignonense PZHK4, around the rhizosphere of P. pinnata grown in soil containing 40 mg kg-1 Ni2+ and without nitrogen addition. The inoculation with both rhizobial strains promoted the growth of P. pinnata under nickel stress or nitrogen-deficiency condition, increased nitrogen content in all plant tissues and nickel content in shoots and leaves, but reduced nickel accumulation in roots. The four non-enzymatic antioxidants including glutathione (GSH), proanthocyanidin (OPC), ascorbic acid (ASA) and flavonoids (FLA) distributed in roots, shoots and leaves were followed in descending order: GSH > OPC > ASA > FLA. The four non-enzymatic antioxidants showed different levels of change under the nitrogen-deficiency and nickel stresses and in the non-stress control. The inoculation of PZHK2 and PZHK4 significantly (p < 0.05) increased the four non-enzymatic antioxidants in P. pinnata tissues, especially in roots. Some non-enzymatic antioxidants showed correlations with nickel or nitrogen in P. pinnata tissues, and the four non-enzymatic antioxidants also had correlations among each other. Therefore, this research revealed an excellent role of rhizobia in promoting non-enzymatic antioxidants to mitigate nitrogen-deficiency or nickel stress for P. pinnata.

DEAP1 encodes a fasciclin-like arabinogalactan protein required for male fertility in rice.

Arabinogalactan proteins (AGPs) are widely distributed in plant cells. Fasciclin-like AGPs (FLAs) belong to a subclass of AGPs that play important roles in plant growth and development. However, little is known about the biological functions of rice FLA. Herein, we report the identification of a male-sterile mutant of DEFECTIVE EXINE AND APERTURE PATTERNING1 (DEAP1) in rice. The deap1 mutant anthers produced aberrant pollen grains with defective exine formation and a flattened aperture annulus and exhibited slightly delayed tapetum degradation. DEAP1 encodes a plasma membrane-associated member of group III plant FLAs and is specifically and temporally expressed in reproductive cells and the tapetum layer during male development. Gene expression studies revealed reduced transcript accumulation of genes related to exine formation, aperture patterning, and tapetum development in deap1 mutants. Moreover, DEAP1 may interact with two rice D6 PROTEIN KINASE-LIKE3s (OsD6PKL3s), homologs of a known Arabidopsis aperture protein, to affect rice pollen aperture development. Our findings suggested that DEAP1 is involved in male reproductive development and may affect exine formation and aperture patterning, thereby providing new insights into the molecular functions of plant FLAs in male fertility.

Synergistic anti-oxidative effects of Pongamia pinnata against nickel mediated by Rhizobium pisi and Ochrobacterium pseudogrignonense.

Nickel is widely spread by different anthropogenic activities and shows toxicity for plant growth and development. Whether rhizobia symbiotically fix nitrogen can eliminate or reduce nickel toxic effect on plant or not is still unknown. This study was aimed to investigate the effect of different rhizobia genus inoculation on growth, nitrogen fixing ability, metal accumulation and enzymatic antioxidative balance of Pongamia pinnnaa. Inoculation with Rhizobium pisi and Ochrobacterium pseudogrignonense increased the all the growth parameters both in 0 and 40 mg/kg nickel as comparison with control. Only shoot length increased in presence of nitrogen as compared with no supply of nitrogen. Nitrogen content also increased both in rhizobia inoculation as compared to no nitrogen supply and non-inoculation control, respectively. Nickel uptake was higher in shoots and leaves but lower in roots in case of inoculation as compared to non-inoculation control. Rhizobia inoculation improved the plant antioxidant capacity by increasing the activity of enzymatic scavengers catalase (CAT), superoxide dismutase (SOD), peroxidase (POD) and ascorbate (GR). However, 40 mg/kg of nickel adding showed mostly effect on the activity CAT, SOD, POD in leaves. All the enzymatic activity showed a significant increase in absence of nitrogen supply as compared nitrogen supply. Our results suggested that rhizobia inoculation effectively mediated nickel stress for legume plants by increasing nitrogen supplement and inducing antioxidant capacity.

A rational-choice model of Covid-19 transmission with endogenous quarantining and two-sided prevention.

This paper offers a parsimonious, rational-choice model to study the effect of pre-existing inequalities on the transmission of COVID-19. Agents decide whether to "go out" (or self-quarantine) and, if so, whether to wear protection such as masks. Three elements distinguish the model from existing work. First, non-symptomatic agents do not know if they are infected. Second, some of these agents unknowingly transmit infections. Third, we permit two-sided prevention via the use of non-pharmaceutical interventions: the probability of a person catching the virus from another depends on protection choices made by each. We find that a mean-preserving increase in pre-existing income inequality unambiguously increases the equilibrium proportion of unprotected, socializing agents and may increase or decrease the proportion who self-quarantine. Strikingly, while higher pre-COVID inequality may or may not raise the overall risk of infection, it increases the risk of disease in social interactions.

WRKY Transcription Factors Shared by BTH-Induced Resistance and NPR1-Mediated Acquired Resistance Improve Broad-Spectrum Disease Resistance in Wheat.

In Arabidopsis, both pathogen invasion and benzothiadiazole (BTH) treatment activate the nonexpresser of pathogenesis-related genes 1 (NPR1)-mediated systemic acquired resistance, which provides broad-spectrum disease resistance to secondary pathogen infection. However, the BTH-induced resistance in Triticeae crops of wheat and barley seems to be accomplished through an NPR1-independent pathway. In the current investigation, we applied transcriptome analysis on barley transgenic lines overexpressing wheat wNPR1 (wNPR1-OE) and knocking down barley HvNPR1 (HvNPR1-Kd) to reveal the role of NPR1 during the BTH-induced resistance. Most of the previously designated barley chemical-induced (BCI) genes were upregulated in an NPR1-independent manner, whereas the expression levels of several pathogenesis-related (PR) genes were elevated upon BTH treatment only in wNPR1-OE. Two barley WRKY transcription factors, HvWRKY6 and HvWRKY70, were predicted and further validated as key regulators shared by the BTH-induced resistance and the NPR1-mediated acquired resistance. Wheat transgenic lines overexpressing HvWRKY6 and HvWRKY70 showed different degrees of enhanced resistance to Puccinia striiformis f. sp. tritici pathotype CYR32 and Blumeria graminis f. sp. tritici pathotype E20. In conclusion, the transcriptional changes of BTH-induced resistance in barley were initially profiled, and the identified key regulators would be valuable resources for the genetic improvement of broad-spectrum disease resistance in wheat.[Formula: see text] Copyright © 2020 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license.

Changes in soil microbial communities at Jinsha earthen site are associated with earthen site deterioration.

BACKGROUND: Earthen sites are immobile cultural relics and an important part of cultural heritage with historical, artistic and scientific values. The deterioration of features in earthen sites result in permanent loss of cultural information, causing immeasurable damage to the study of history and culture. Most research on the deterioration of earthen sites has concentrated on physicochemical factors, and information on microbial communities in earthen sites and their relationship with the earthen site deterioration is scarce. We used high-throughput sequencing to analyze bacterial and fungal communities in soils from earthen walls with different degree of deterioration at Jinsha earthen site to characterize the microbial communities and their correlation with environmental factors, and to compare microbial community structures and the relative abundances of individual taxa associated with different degree of deterioration for identifying possible marker taxa. RESULTS: The relative abundances of Proteobacteria and Firmicutes were higher and that of Actinobacteria lower with higher degree of deterioration. At the genus level, the relative abundances of Rubrobacter were highest in all sample groups except in the most deteriorated samples where that of Bacteroides was highest. The relative abundance of the yeast genus Candida was highest in the severely deteriorated sample group. The bacterial phylum Bacteroidetes and genus Bacteroides, and fungal class Saccharomycetes that includes Candida sp. were specific for the most deteriorated samples. For both bacteria and fungi, the differences in community composition were associated with differences in EC, moisture, pH, and the concentrations of NH4+, K+, Mg2+, Ca2+ and SO42-. CONCLUSION: The microbial communities in soil with different degree of deterioration were distinctly different, and deterioration was accompanied with bigger changes in the bacterial than in the fungal community. In addition, the deteriorated soil contained higher concentrations of soluble salts. Potentially, the accumulation of Bacteroides and Candida plays an important role in the deterioration of earthen features. Further work is needed to conclude whether controlling the growth of the bacteria and fungi with high relative abundances in the deteriorated samples can be applied to alleviate deterioration.