Development of SNP and InDel markers by genome resequencing and transcriptome sequencing in radish (Raphanus sativus L.).

BACKGROUND: Single nucleotide polymorphisms (SNPs) and insertions/deletions (InDels) are the most abundant genetic variations and widely distribute across the genomes in plant. Development of SNP and InDel markers is a valuable tool for genetics and genomic research in radish (Raphanus sativus L.). RESULTS: In this study, a total of 366,679 single nucleotide polymorphisms (SNPs) and 97,973 insertion-deletion (InDel) markers were identified based on genome resequencing between 'YZH' and 'XHT'. In all, 53,343 SNPs and 4,257 InDels were detected in two cultivars by transcriptome sequencing. Among the InDel variations, 85 genomic and 15 transcriptomic InDels were newly developed and validated PCR. The 100 polymorphic InDels markers generated 207 alleles among 200 Chinese radish germplasm, with an average 2.07 of the number of alleles (Na) and with an average 0.33 of the polymorphism information content (PIC). Population structure and phylogenetic relationship revealed that the radish cultivars from northern China were clustered together and the southwest China cultivars were clustered together. RNA-Seq analysis revealed that 11,003 differentially expressed genes (DEGs) were identified between the two cultivars, of which 5,020 were upregulated and 5,983 were downregulated. In total, 145 flowering time-related DGEs were detected, most of which were involved in flowering time integrator, circadian clock/photoperiod autonomous, and vernalization pathways. In flowering time-related DGEs region, 150 transcriptomic SNPs and 9 InDels were obtained. CONCLUSIONS: The large amount of SNPs and InDels identified in this study will provide a valuable marker resource for radish genetic and genomic studies. The SNPs and InDels within flowering time-related DGEs provide fundamental insight into for dissecting molecular mechanism of bolting and flowering in radish.

Fine mapping and analysis of candidate genes for qBT2 and qBT7.2 locus controlling bolting time in radish (Raphanus sativus L.).

KEY MESSAGE: Two major QTLs for bolting time in radish were mapped to chromosome 02 and 07 in a 0.37 Mb and 0. 52 Mb interval, RsFLC1 and RsFLC2 is the critical genes. Radish (Raphanus sativus L.) is an important vegetable crop of Cruciferae. The premature bolting and flowering reduces the yield and quality of the fleshy root of radish. However, the molecular mechanism underlying bolting and flowering in radish remains unknown. In YZH (early bolting) × XHT (late bolting) F2 population, a high-density genetic linkage map was constructed with genetic distance of 2497.74 cM and an average interval of 2.31 cM. A total of nine QTLs for bolting time and two QTLs for flowering time were detected. Three QTLs associated with bolting time in radish were identified by QTL-seq using radish GDE (early bolting) × GDL (late bolting) F2 population. Fine mapping narrowed down qBT2 and qBT7.2 to an 0.37 Mb and 0.52 Mb region on chromosome 02 and 07, respectively. RNA-seq and qRT-PCR analysis showed that RsFLC1 and RsFLC2 were the candidate gene for qBT7.2 and qBT2 locus, respectively. Subcellular localization exhibited that RsFLC1 and RsFLC2 were mainly expressed in the nucleus. A 1856-bp insertion in the first intron of RsFLC1 was responsible for bolting time. Overexpression of RsFLC2 in Arabidopsis was significantly delayed flowering. These findings will provide new insights into the exploring the molecular mechanism of late bolting and promote the marker-assisted selection for breeding late-bolting varieties in radish.

Deciphering biochar compost co-application impact on microbial communities mediating carbon and nitrogen transformation across different stages of corn development.

Under current climatic conditions, developing eco-friendly and climate-smart fertilizers has become increasingly important.The co-application of biochar and compost on agricultural soils has received considerable attention recently.Unfortunately, little is known about its effects on specific microbial taxa involved in carbon and nitrogen transformation in the soil.Herein, we report the efficacy of applying biochar-based amendments on soil physicochemical indices, enzymatic activity, functional genes, bacterial community, and their network patterns in corn rhizosphere at seedling (SS), flowering (FS), and maturity (MS) stages.The applied treatments were: compost alone (COM), biochar alone (BIOC), composted biochar (CMB), fortified compost (CMWB), and the control (no fertilizer (CNTRL).The non-metric multidimensional scaling (NMDS) indicated total nitrogen (TN), pH, NO3--N, urease, protease, and microbial biomass C (MBC) as the dominant environmental factors driving soil bacteria in this study.The dominant N mediating genes belonged to nitrate reductase (narG) and nitronate monooxygenase (amo), while beta-galactosidase, catalase, and alpha-amylase were the dominant genes observed relating to C cycling.Interestingly, the abundance of these genes was higher in COM, CMWB, and CMB compared with the CNTRL and BIOC treatments.The bacteria network properties of CWMB and CMB indicated robust niche overlap associated with high cross-feeding between bacterial communities compared to other treatments.Path and stepwise regression analyses revealed norank_Reyranellaceae and Sphingopyxis in CMWB as the major bacterial genera and the major predictive indices mediating soil organic C (SOC), NH4+-N, NO3--N, and TN transformation.Overall, biochar with compost amendments improved soil nutrient conditions, regulated the composition of the bacterial community, and benefited C/N cycling in the soil ecosystem.

Exploration of ß-glucosidase-producing microorganisms community structure and key communities driving cellulose degradation during composting of pure corn straw by multi-interaction analysis.

Poor management of crop residues leads to environmental pollution and composting is a sustainable practice for addressing the challenge. However, knowledge about composting with pure crop straw is still limited, which is a novel and feasible composting strategy. In this study, pure corn straw was in-situ composted for better management. Community structure of ß-glucosidase-producing microorganisms during composting was deciphered using high-throughput sequencing. Results showed that the compost was mature with organic matter content of 37.83% and pH value of 7.36 and pure corn straw could be composted successfully. Cooling phase was major period for cellulose degradation with the highest ß-glucosidase activity (476.25 µmol·p-Nitr/kg·dw·min) and microbial diversity (Shannon index, 3.63; Chao1 index, 500.81). Significant compositional succession was observed in the functional communities during composting with Streptomyces (14.32%), Trichoderma (13.85%) and Agromyces (11.68%) as dominant genera. ß-Glucosidase-producing bacteria and fungi worked synergistically as a network to degrade cellulose with Streptomyces (0.3045**) as the key community revealed by multi-interaction analysis. Organic matter (-0.415***) and temperature (-0.327***) were key environmental parameters regulating cellulose degradation via influencing ß-glucosidase-producing communities, and ß-glucosidase played a key role in mediating this process. The above results indicated that responses of ß-glucosidase-producing microorganisms to cellulose degradation were reflected at both network and individual levels and multi-interaction analysis could better explain the relationship between variables concerning composting cellulose degradation. The work is of significance for understanding cellulose degradation microbial communities and process during composting of pure corn straw.

Dynamics of fungal species related to nitrogen transformation and their network patterns during cattle manure-corn straw with biochar composting.

Fungi are reputed to play a significant role in the composting matrix as decomposers of recalcitrant organic materials like cellulose and lignin. However, information on the fungi communities' roles in nitrogen transformation under a compost-biochar mixture is scarce. This study investigated shifts in fungal species mediating N transformation and their network patterns in cattle manure-corn straw (CMCS) and CMCS plus biochar (CMCB) composting using high-throughput sequencing data. The results revealed that the addition of biochar altered fungal richness and diversity and significantly influenced their compositions during composting. Biochar also altered the compost fungal network patterns; CMCS had a more complex network with higher positive links than CMCB, suggesting stable niche overlap. The consistent agreement of multivariate analyses (redundancy, network, regression, Mantel and path analyses) indicated that Ciliophora_sp in CMCS and unclassified_norank_Pleosporales in CMCB were the key fungal species mediating total N transformation, whereas Scedosporium_prolificans in CMCS and unclassified_Microascaceae in CMCB were identified as major predictive indices determining NO3--N transformation. Also, Coprinopsis cinerea and Penicillium oxalicum were the predictive factors for NH4+-N transformation in CMCS and CMCB during composting. These results indicated that the effects of biochar on N conversions in composting could be unraveled using multivariate analyses on fungi community evolution, network patterns, and metabolism.

Diagnostic value comparison of CellDetect, fluorescent in situ hybridization (FISH), and cytology in urothelial carcinoma.

BACKGROUND: To evaluate the clinical effectiveness of a novel CellDetect staining technique, compared with fluorescent in situ hybridization (FISH), and urine cytology, in the diagnosis of urothelial carcinoma (UC). METHODS: A total of 264 patients with suspicious UC were enrolled in this study. All tissue specimens were collected by biopsy or surgery. Urine specimen was obtained for examinations prior to the surgical procedure. CellDetect staining was carried out with CellDetect kit, and FISH was performed with UroVysion detection kit, according to the manufacturer's instructions. For urine cytology, all specimens were centrifuged using the cytospin method, and the slides were stained by standard Papanicolaou stain. RESULTS: In this study, there were 128 cases of UC and 136 cases of non-UC, with no significant difference in gender and age between the two groups. Results for sensitivity of CellDetect, FISH, and urine cytology were 82.8%, 83.6%, and 39.8%, respectively. The specificity of the three techniques were 88.2%, 90.4%, and 86.0%, respectively. The sensitivity of CellDetect and FISH are significantly superior compared to the conventional urine cytology; however, there was no significant difference in specificity among three staining techniques. In addition, the sensitivity of CellDetect in lower urinary tract UC, upper urinary tract UC, non-muscle-invasive bladder cancer (NMIBC), and muscle-invasive bladder cancer (MIBC) were 83.3%, 81.8%, 83.5%, and 72.0%, respectively. The screening ability of CellDetect has no correlation with tumor location and the tumor stage. The sensitivity of CellDetect in low-grade UC and high-grade UC were 51.6 and 92.8%. Thus, screening ability of CellDetect in high-grade UC is significantly superior compared to that in low-grade UC. CONCLUSIONS: CellDetect and FISH show equal value in diagnosing UC, both are superior to conventional urine cytology. Compared to FISH, CellDetect is cost effective, easy to operate, with extensive clinical application value to monitor recurrence of UC, and to screen indetectable UC.

Biochar reduces nutrient loss and improves microbial biomass of composted cattle manure and maize straw.

In this study, nutrient loss, the direct and indirect relationship between period, compost types, temperature, total nitrogen (TN), nitrate nitrogen (NO3 - -N), ammonium nitrogen (NH4 + -N), microbial biomass carbon (MBC), and microbial biomass nitrogen (MBN) were investigated during composting of cattle manure-maize straw mixture. This study findings revealed that biochar addition lowered NH4 + -N but did not increase NO3 - -N concentrations unlike no biochar piles during composting. The first-order kinetic models showed that biochar accelerated organic matter (OM) degradation and improved nitrogen mineralization, consequently reducing TN losses by 13.6% and OM losses by 12.66%. Transformation ratio of MBC/MBN, coupled with other chemical components of the entire microbial community, suggested a shift in the microbial succession and diversity during composting from the dominant bacteria and actinomycetes to fungi. The structural equation model and path coefficient revealed temperature to be the main factor mediating the evolution of MBC and MBN in composting. The physicochemical variables, phytotoxicity, and final product quality revealed that biochar incorporation to the composting feedstock is an ideal material for mitigating problems of TN and OM losses in composting and ultimately enhancing the fertility potential of the final compost product.

Differences in distribution of functional microorganism at DNA and cDNA levels in cow manure composting.

Denitrification and nitrification processes are the two prominent pathways of nitrogen (N) transformation in composting matrix. This study explored the dynamics of denitrifying and nitrifying bacteria at different composting stages of cow manure and corn straw using functional gene sequencing at DNA and cDNA levels. Corresponding agreement among OTUs, NMDS, mental test and network analyses revealed that functional bacteria community compositions and responses to physicochemical factors were different at DNA and cDNA levels. Specifically, some OTUs were detected at the DNA level but were not observed at cDNA level, differences were also found in the distribution patterns of nitrifying and denitrifying bacteria communities at both levels. Furthermore, co-occurrence network analysis indicated that Pseudomonas, Paracoccus and Nitrosomonas were identified as the keystone OTUs at the DNA level, while Paracoccus, Agrobacterium and Nitrosospira were keystone OTUs at the cDNA level. Mantel test revealed that TN, C/N and moisture content significantly influenced both the denitrifying bacteria and ammonia-oxidizing bacteria (AOB) communities at the DNA level. NO3--N, NH4+-N, TN, C/N, and moisture content only registered significant correlation with the nosZ-type denitrifiers and ammonia-oxidizing bacteria (AOB) communities at the cDNA level. Structural equation model (SEM) showed that TN, NH4+-N, and pH were direct and significantly influenced the gene abundance of denitrifying bacteria. Howbeit, TN, NH4+-N, and NO3--N had significant direct effects on amoA gene abundance.

Bacterial community succession in dairy manure composting with a static composting technique.

This study applied high-throughput sequencing technology and PICRUSt (phylogenetic investigation of communities by reconstruction of unobserved state) to examine the microbial population dynamics during the composting of dairy manure and rice straw in a static (without turning) composting system. The results showed that the composition of the bacterial community varied significantly during the composting process. The dominant phyla included Firmicutes, Proteobacteria, Bacteroidetes, Actinobacteria, and Chloroflexi. Biodiversity indices showed that bacterial community diversity had the peak value during the mesophilic phase. Redundancy analysis indicated that nitrogen was the most important factor in the distribution of genera during the composting process. Finally, the Pearson correlation results suggested that Thermomonospora and Thermopolyspora could be the biomarkers of the composting maturation phase. The metabolic characteristics of the bacterial communities were predicted by PICRUSt. The result showed that metabolism of amino acids, lipids, and most of the carbohydrates increased during the whole composting treatment. However, methane metabolism, carbon fixation pathways in prokaryotes, and nucleotide metabolism decreased after the thermophilic phase. The present study provides a better understanding for bacterial community composition and function succession in dairy manure composting.

Correlation between ammonia-oxidizing microorganisms and environmental factors during cattle manure composting.

Cattle manure composting was performed in an aerated vessel. Community structure and diversity of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) were investigated using polymerase chain reaction and denaturing gradient gel electrophoresis (PCR-DGGE) techniques targeting the ammonia monooxygenase alpha subunit (amoA) gene and the correlation between AOB and AOA communities and environmental factors was explored. Thirteen (13) AOB sequences were obtained, which were closely related to Nitrosomonas spp., Nitrosomonas eutropha, and Nitrosospira spp. and uncultured bacteria, among which Nitrosomonas spp. were predominant. Excessively high temperature and high ammonium concentration were not favorable for AOB growth. Five AOA sequences, belonging to CandidatusNitrososphaera gargensis and to an uncultured archaeon, were obtained. During composting, community diversity of AOB and AOA fluctuated, with AOA showing a higher Shannon-Wiener index. The AOB community changed more dramatically in the mesophilic stage and the early thermophilic stage, whereas the most obvious AOA community succession occurred in the late thermophilic stage, the cooling stage and the maturity stage. Water content, total nitrogen (TN) and ammonium concentration were more relevant to the AOB community structure, while higher correlations were observed between ammonia, nitrate and TN and the AOA community. AOB community diversity was negatively correlated with pH (r = -0.938, p < 0.01) and water content (r = -0.765, p < 0.05), while positively correlated with TN (r = 0.894, p < 0.01). AOA community diversity was negatively correlated with ammonium concentration (r = -0.901, p < 0.01). Ammonium concentration played an important role in the succession of AOB and AOA communities during composting.

Diversity and abundance of denitrifiers during cow manure composting.

Diversity and abundance of the denitrifying genes nirK, nirS and nosZ were investigated in cow manure compost using polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) and real-time quantitative PCR (qPCR), respectively. These three genes were detected in all the stages of the composting process. Phylogenetic analysis showed that the nirK gene was closely related to Rhizobiales, Burkholderiales, the nirS gene was closely related to Pseudomonadales and Burkholderiales, and the nosZ gene was closely related to Rhodospirillales, Rhizobiales, Pseudomonadales, and Alteromonadales. qPCR results showed that the abundance of these three genes (nirK, nirS and nosZ) reached the peak value in the late thermophilic stage of composting and abundance of the nirK gene was higher than that of the nosZ gene and the nirS gene. Redundancy analysis (RDA) showed that the diversity of the nirK and nirS genes was significantly correlated with ammonium (p<0.05), the diversity of the nosZ gene was significantly correlated with pH (p<0.05) and the abundance of the nirK nirS and nosZ genes was significantly correlated with temperature (p<0.05).

Aliibacillus thermotolerans gen. nov., sp. nov.: a thermophilic and heterotrophic ammonia-oxidizing bacterium from compost.

A novel moderately thermophilic and heterotrophic ammonia-oxidizing bacterium, designated strain BM62T, was isolated from compost in the thermophilic stage in Harbin, China. Phylogenetic analysis based on the 16S rRNA gene indicated that strain BM62T belongs to the family Bacillaceae within the class Bacilli and was most closely related to Alteribacillus iranensis X5BT (only 94.6% sequence similarity). Cells of strain BM62T were Gram-positive, rod-shaped, motile by periflagella, catalase-positive and oxidase-negative. Growth of strain BM62T was observed at salinities of 0-4% (optimum 2-3%), temperatures of 35-65 °C (optimum 50 °C) and pH values of 5-9 (optimum pH 7). The major cellular fatty acid was iso-C16:0, and the predominant ubiquinone was MK-7. The peptidoglycan type is A1γ, and meso-diaminopimelic acid was the diagnostic diamino acid. The major polar lipids were diphosphatidylglycerol, phospholipid and phosphatidylglycerol. The G + C content of its genomic DNA was 36.5 mol%. Data from this polyphasic taxonomy study suggested that strain BM62T should be classified as the type strain of the type species of a new genus within the family Bacillaceae for which the name Aliibacillus thermotolerans gen. nov., sp. nov. is proposed. The type strain of the species Aliibacillus thermotolerans sp. nov. is BM62T (= DSM 101851T = CGMCC 1.15790T). The respective DPD Taxon Number is GA00057.

Geodermatophilus daqingensis sp. nov., isolated from petroleum-contaminated soil.

A novel Gram-positive actinobacterium, designated WT-2-1T, was isolated from a sample of petroleum-contaminated soil collected in Daqing, Heilongjiang province, China and characterised using a polyphasic taxonomic approach. The optimal growth for strain WT-2-1T was found to be at 25-35 °C and at pH 6.0-9.0 and with 0-4% (w/v) NaCl, forming blackish green-coloured colonies. Chemotaxonomic and molecular characteristics of the isolate match those described for members of the genus Geodermatophilus. The peptidoglycan was found to contain meso-diaminopimelic acid; galactose, glucose and xylose were detected as diagnostic sugars. The main phospholipids were identified as diphosphatidylglycerol, phosphatidylcholine, phosphatidylinositol, phosphatidylethanolamine and phosphatidylglycerol; MK-9(H4) was the dominant menaquinone present. The major cellular fatty acids were identified as iso-C16:0 and iso-C15:0. 16S rRNA gene sequence analysis showed that strain WT-2-1T is a member of the genus Geodermatophilus, with high sequence similarities to Geodermatophilus aquaeductus BMG801T (98.4%), Geodermatophilus saharensis CF5/5T (98.4%), Geodermatophilus bullaregiensis BMG841T (98.3%) and Geodermatophilus normandii CF5/3T (98.3%). Based on the phenotypic characteristics, phylogenetic data and DNA-DNA hybridization results, the isolate is concluded to represent a novel species of the genus Geodermatophilus, for which the name Geodermatophilus daqingensis sp. nov. is proposed. The type strain is WT-2-1T (=CGMCC 4.7381T = DSM 104001T).

The distribution of active ß-glucosidase-producing microbial communities in composting.

The composting ecosystem is a suitable source for the discovery of novel microorganisms and secondary metabolites. Cellulose degradation is an important part of the global carbon cycle, and ß-glucosidases complete the final step of cellulose hydrolysis by converting cellobiose to glucose. This work analyzes the succession of ß-glucosidase-producing microbial communities that persist throughout cattle manure - rice straw composting, and evaluates their metabolic activities and community advantage during the various phases of composting. Fungal and bacterial ß-glucosidase genes belonging to glycoside hydrolase families 1 and 3 (GH1 and GH3) amplified from DNA were classified and gene abundance levels were analyzed. The major reservoirs of ß-glucosidase genes were the fungal phylum Ascomycota and the bacterial phyla Firmicutes, Actinobacteria, Proteobacteria, and Deinococcus-Thermus. This indicates that a diverse microbial community utilizes cellobiose. The succession of dominant bacteria was also detected during composting. Firmicutes was the dominant bacteria in the thermophilic phase of composting; there was a shift to Actinomycetes in the maturing stage. Proteobacteria accounted for the highest proportions during the heating and thermophilic phases of composting. By contrast, the fungal phylum Ascomycota was a minor microbial community constituent in thermophilic phase of composting. Combined with the analysis of the temperature, cellulose degradation rate and the carboxymethyl cellulase and ß-glucosidase activities showed that the bacterial GH1 family ß-glucosidase genes make greater contribution in cellulose degradation at the later thermophilic stage of composting. In summary, even GH1 bacteria families ß-glucosidase genes showing low abundance in DNA may be functionally important in the later thermophilic phase of composting. The results indicate that a complex community of bacteria and fungi expresses ß-glucosidases in compost. Several ß-glucosidase-producing bacteria and fungi identified in this study may represent potential indicators of composting in cellulose degradation.

Evaluation of microbial population dynamics in the co-composting of cow manure and rice straw using high throughput sequencing analysis.

Microbial population dynamics in co-composting of cow manure and rice straw were evaluated using 16S high throughput sequencing technology. Physicochemical factors, including temperature, pH, nitrogen contents, the ratio of carbon and nitrogen, and germination index, were also determined in this study. 16S high throughput sequencing results showed that bacterial community structure and composition significantly varied in each phase of composting. The major phyla included Bacteroidetes, Proteobacteria, Firmicutes, Actinobacteria and Planctomycetes, respectively. Bacteroidetes and Proteobacteria were the most abundant phyla in all phases, and Actinobacteria was just dominant in the mesophilic phase, while Firmicutes and Planctomycetes were ubiquitous. At the genus level, Simiduia, Flavobacterium, unclassified Chitinophagaceae and Flexibacter notably changed in each phase of composting. Bacterial community diversity in the mesophilic phase was higher than that in others based on the Shannon-Wiener index and Simpson diversity index. The ratio of carbon and nitrogen and germination index indicated that the co-composting of cow manure and rice straw reached maturation. The result of nitrogen contents showed that nitrogen loss mainly occurred in the thermophilic phase. In addition, the differences in the distributions of key OTUs between in the late thermophilic phase and the cooling and maturation phase were unobvious compared with other phase's base on the principal component analysis. Redundancy analysis revealed that the changes of nitrogen played a predominant role in the distributions of OTUs during the composting process.

Impacts of drought stress on soluble carbohydrates and respiratory enzymes in fruit body of Auricularia auricula.

In order to study the survival mechanisms to drought stress for fruit body of Auricularia auricula, soluble carbohydrates and respiratory enzymes were investigated. Fruit bodies were exposed to sunlight and were naturally dehydrated. Samples were taken at different levels of water loss (0%, 10%, 30%, 50% and 70%) to measure the content of soluble sugars and polysaccharides. The activities of phosphoglucose isomerase (PGI), combined glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH), and malate dehydrogenase (MDH), were also determined. The results showed that with the increase in water loss, soluble sugars and MDH activity declined, whereas the activities of G-6-PDH and 6-PGDH increased. Soluble polysaccharides content and PGI activity decreased with water loss up to 30% and increased afterwards. These results suggested that the pentose phosphate pathway (PPP), as demonstrated by activities of G-6-PDH and 6-PGDH, could be one of the mechanisms for survival during drought stress in the fruit body of A. auricula. Moreover, soluble polysaccharides may play a part in protecting the fruit body in further drought stress.

Responses of antioxidant defenses and membrane damage to drought stress in fruit bodies of Auricularia auricula-judae.

Fruit bodies of Auricularia auricula-judae are often subjected to drought stress and became dormant. The responses of antioxidant defenses and membrane damage to drought stress were investigated in this study. Picked fruit bodies were exposed to sunlight and dehydrated naturally and samples were collected at different levels of water loss (0, 10, 30, 50, and 70%) for determination of electrolyte leakage (EL); contents of malondialdehyde (MDA), ascorbic acid (AsA) and reduced glutathione (GSH); and activities of superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD). Results showed that membrane permeability (assessed by EL) and membrane lipid peroxidation (MDA content) remained unchanged at all levels of water loss studied. Contents of AsA and GSH showed no change at 0, 10 and 30% of water loss, however, both of them increased significantly at 50 and 70% of water loss. SOD activity significantly increased with the rising of water loss from 0 to 30%, reached the peak at 30 and 50% of water loss, and then significantly decreased at 70% of water loss. A gradual increase in POD and CAT activities was observed when water loss rose from 0 to 50%. As water loss went up to 70%, POD activity remained the same as that at 50%, but CAT activity decreased. The results indicate that the increased activities of enzymatic antioxidants (SOD, CAT and POD) and contents of non-enzymatic antioxidants (AsA and GSH) in fruit bodies of A. auricula-judae can effectively scavenge reactive oxygen species, cause no damage to cell membranes as demonstrated by the unchanged EL and MDA content, and contribute to dormancy under drought stress.

Insight into N2O emission and denitrifier communities under different aeration intensities in composting of cattle manure from perspective of multi-factor interaction analysis.

Nitrous oxide (N2O) emission from composting is a significant contributor to greenhouse effect and ozone depletion, which poses a threat to environment. To address the challenge of mitigating N2O emission during composting, this study investigated the response of N2O emission and denitrifier communities (detected by metagenome sequencing) to aeration intensities of 6 L/min (C6), 12 L/min (C12), and 18 L/min (C18) in cattle manure composting using multi-factor interaction analysis. Results showed that N2O emission occurred mainly at mesophilic phase. Cumulative N2O emission (QN2O, 9.79 mg·kg-1 DW) and total nitrogen loss (TN loss, 16.40 %) in C12 composting treatment were significantly lower than those in the other two treatments. The lower activity of denitrifying enzymes and the more complex and balanced network of denitrifiers and environmental factors might be responsible for the lower N2O emission. Denitrification was confirmed to be the major pathway for N2O production. Moisture content (MC) and Luteimonas were the key factors affecting N2O emission, and nosZ-carrying denitrifier played a significant role in reducing N2O emission. Although relative abundance of nirS was lower than that of nirK significantly (P < 0.05), nirS was the key gene influencing N2O emission. Community composition of denitrifier varied significantly with different aeration treatments (R2 = 0.931, P = 0.001), and Achromobacter was unique to C12 at mesophilic phase. Physicochemical factors had higher effect on QN2O, whereas denitrifying genes, enzymes and NOX- had lower effect on QN2O in C12. The complex relationship between N2O emission and the related factors could be explained by multi-factor interaction analysis more comprehensively. This study provided a novel understanding of mechanism of N2O emission regulated by aeration intensity in composting.

Improving prediction of N2O emissions during composting using model-agnostic meta-learning.

Nitrous oxide (N2O) represents a significant environmental challenge as a harmful, long-lived greenhouse gas that contributes to the depletion of stratospheric ozone and exacerbates global anthropogenic greenhouse warming. Composting is considered a promising and economically feasible strategy for the treatment of organic waste. However, recent research indicates that composting is a source of N2O, contributing to atmospheric pollution and greenhouse effect. Consequently, there is a need for the development of effective, cost-efficient methodologies to quantify N2O emissions accurately. In this study, we employed the model-agnostic meta-learning (MAML) method to improve the performance of N2O emissions prediction during manure composting. The highest R2 and lowest root mean squared error (RMSE) values achieved were 0.939 and 18.42 mg d-1, respectively. Five machine learning methods including the backpropagation neural network, extreme learning machine, integrated machine learning method based on ELM and random forest, gradient boosting decision tree, and extreme gradient boosting were adopted for comparison to further demonstrate the effectiveness of the MAML prediction model. Feature analysis showed that moisture content of structure material and ammonium concentration during composting process were the two most significant features affecting N2O emissions. This study serves as proof of the application of MAML during N2O emissions prediction, further giving new insights into the effects of manure material properties and composting process data on N2O emissions. This approach helps determining the strategies for mitigating N2O emissions.

Characterization of OsMIK in a rice mutant with reduced phytate content reveals an insertion of a rearranged retrotransposon.

The rice low phytic acid (lpa) mutant Os-lpa-XS110-1(XS-lpa) has ~45 % reduction in seed phytic acid (PA) compared with the wild-type cultivar Xiushui 110. Previously, a single recessive gene mutation was shown to be responsible for the lpa phenotype and was mapped to a region of chromosome 3 near OsMIK (LOC_Os03g52760) and OsIPK1 (LOC_Os03g51610), two genes involved in PA biosynthesis. Here, we report the identification of a large insert in the intron of OsMIK in the XS-lpa mutant. Sequencing of fragments amplified through TAIL-PCRs revealed that the insert was a derivative of the LINE retrotransposon gene LOC_Os03g56910. Further analyses revealed the following characteristics of the insert and its impacts: (1) the inserted sequence of LOC_Os03g56910 was split at its third exon and rejoined inversely, with its 5' and 3' flanking sequences inward and the split third exon segments outward; (2) the LOC_Os03g56910 remained in its original locus in XS-lpa, and the insertion probably resulted from homologous recombination repair of a DNA double strand break; (3) while the OsMIK transcripts of XS-lpa and Xiushui 110 were identical, substantial reductions of the transcript abundance (~87 %) and the protein level (~60 %) were observed in XS-lpa, probably due to increased methylation in its promoter region. The above findings are discussed in the context of plant mutagenesis, epigenetics and lpa breeding.