Increasing prolificacy is an important aim in the pig industry.  Regions associated with litter size have been revealed, but detailed molecular mechanisms are unclear.  The Meishan pig is one of the most prolific breeds, with higher prolificacy than the Yorkshire pig, which exhibits high feeding efficiency and lean meat yield.  The ovary is the key organ determining reproductive traits during pregnancy by synthesizing and secreting reproductive hormones essential for conceptus maintenance.  In this comparative multi-omics study of the ovary transcriptome, proteome, and metabolome on day 49 of pregnancy, we aimed to identify genomic, proteomic, and metabolomic differences between the ovaries of Meishan and Yorkshire pigs to reveal potential molecular mechanisms conferring high prolificacy.  Meishan pigs demonstrated general downregulation of steroid biosynthesis and butanoate metabolism in the ovary during mid-pregnancy at both transcriptome and proteome levels but exhibited higher serum cholesterol, estradiol, and progesterone levels than Yorkshire pigs.  We also identified several single-nucleotide polymorphisms in the genes of the steroid hormone pathway associated with litter number, average birth weight, and total litter weight.  Lower biosynthesis rates but elevated serum levels of reproductive hormones during mid- and late pregnancy are essential for the greater prolificacy of Meishan pigs.

Chromatin accessibility plays a vital role in gene transcriptional regulation.  However, the regulatory mechanism of chromatin accessibility, as well as its role in regulating crucial gene expression and kernel development in maize (Zea mays) are poorly understood.  In this study, we isolated a maize kernel mutant designated as defective kernel219 (dek219), which displays opaque endosperm and embryo abortion.  Dek219 encodes the DICER-LIKE1 (DCL1) protein, an essential enzyme in miRNA biogenesis.  Loss of function of Dek219 results in significant reductions in the expression levels of most miRNAs and histone genes.  Further research showed that the Heat shock transcription factor17 (Hsf17)-Zm00001d016571 module may be one of the factors affecting the expression of histone genes.  Assay results for transposase-accessible chromatin sequencing (ATAC-seq) indicated that the chromatin accessibility of dek219 is altered compared with that of wild type (WT), which may regulate the expression of crucial genes in kernel development.  By analyzing differentially expressed genes (DEGs) and differentially accessible chromatin regions (ACRs) between WT and dek219, we identified 119 candidate genes that are regulated by chromatin accessibility, including some reported to be crucial genes for kernel development.  Taken together, these results suggest that Dek219 affects chromatin accessibility and the expression of crucial genes that are required for maize kernel development

Understanding the spatial-temporal dynamics of crop nitrogen (N) use efficiency (NUE) and the relationship with explanatory environmental variables can support land-use management and policymaking.  Nevertheless, the application of statistical models for evaluating the explanatory variables of space-time variation in crop NUE is still under-researched.  In this study, stepwise multiple linear regression (SMLR) and Random Forest (RF) were used to evaluate the spatial and temporal variation of NUE indicators (i.e., partial factor productivity of N (PFP_N); partial nutrient balance of N (PNB_N)) at county scale in Northeast China (Heilongjiang, Liaoning and Jilin provinces) from 1990 to 2015.  Explanatory variables included agricultural management practices, topography, climate, economy, soil and crop types.  Results revealed that the PFP_N was higher in the northern parts and lower in the center of the Northeast China and PNB_N increased from southern to northern parts during the 1990–2015 period.  The NUE indicators decreased with time in most counties during the study period.  The model efficiency coefficients of the SMLR and RF models were 0.44 and 0.84 for PFP_N, and 0.67 and 0.89 for PNB_N, respectively.  The RF model had higher relative importance of soil and climatic covariates and lower relative importance of crop covariates compared to the SMLR model.  The planting area index of vegetables and beans, soil clay content, saturated water content, enhanced vegetation index in November & December, soil bulk density, and annual minimum temperature were the main explanatory variables for both NUE indicators.  This is the first study to show the quantitative relative importance of explanatory variables for NUE at a county level in Northeast China using RF and SMLR.  This novel study gives reference measurements to improve crop NUE which is one of the most effective means of managing N for sustainable development, ensuring food security, alleviating environmental degradation and increasing farmer’s profitability.

β-Glucosidase belongs to the glycoside hydrolase I family, which is widely present in multiple species and responds to various biotic and abiotic stresses. In rice, whether β-glucosidase is involved in the interaction between plants and microorganisms is not clear. In this study, we found that the expression of several genes encoding β-glucosidases, including OsBGLU19 and OsBGLU23, were upregulated after inoculation with Xanthomonas oryzae pv. oryzicola (Xoc) and downregulated after inoculation with X. oryzae pv. oryzae (Xoo). The respective insertion mutants of OsBGLU19 and OsBGLU23, bglu19 and bglu23, were more susceptible to Xoc infection. The expression of OsAOS2, a key gene in the jasmonic acid signal pathway, was dramatically downregulated after inoculation with Xoc in the bglu19 and bglu23 mutants. Simultaneously, the expression of downstream disease resistance-related genes, such as OsPR1a, OsPR5 and a key transcription factors OsWRKY72 were obviously downregulated. The resistance mediated by OsBGLU19 and OsBGLU23 to bacterial leaf streak is related to disease resistance-related genes above mentioned.

Insects have developed a good adaptive mechanism in response to environmental stresses in the long-term evolution.
They have developed a helpful metabolism system to resist plant allelochemicals. Insects also harbor different kinds of
symbiotic bacteria, which provide them a competitive advantage. Here, using cotton aphid as an example, we investigated
the effects of four plant allelochemicals on the differential expression of symbiotic bacteria based on transcriptome data.
We also studied the composition of symbiotic bacteria and function on pathway level in three kinds of aphids. We found that
the bacteria have a significant role in resisting the plant allelochemicals stress and host plant selection by aphids. These
results should be useful to investigate the environmental adaption mechanism of aphids in the view of symbiotic bacteria.
These results would offer a new insight for improving strategy of aphids and developing new pest control systems.

The root-knot nematode Meloidogyne graminicola, which is distributed worldwide, is considered a major constraint on rice production in Asia.  The present study used the root gall index and number of nematodes inside the roots to evaluate resistance/susceptibility to M. graminicola in different subpopulations of Oryza sativa (aus, hybrid aus, indica, hybrid indica, temperate japonica, tropical japonica).  Nematode development in highly resistant varieties was also evaluated.  Analyses of randomly selected 35 varieties showed the number of M. graminicola nematodes inside the roots correlated very strongly (r=0.87, P≤0.05) with the nematode gall index, and the results from pot and field experiments revealed similar rankings of the varieties for resistance/susceptibility.  Among the 136 tested varieties, temperate japonica displayed the highest gall index, followed by tropical japonica, indica, hybrid indica, aus, and hybrid aus. Zhonghua 11 (aus), Shenliangyou 1 (hybrid aus) and Cliangyou 4418 (hybrid indica) were highly resistant to M. graminicola under both pot and field conditions.  Further examination of nematode development suggested that compared to susceptible rice, M. graminicola penetrated less often into highly resistant varieties and more frequently failed to develop into females.  The promising varieties found in the present research might be useful for the breeding of hybrid rice in China and for the further development of practical nematode management measures.   

Effects of four different drying methods on the colour, texture, sensory quality, microstructure, bacterial viability and storage stability of probiotic-enriched apple snacks were assessed.  The drying methods were air drying (AD), freeze drying (FD), freeze drying followed by microwave vacuum drying (FD+MVD) and air drying followed by explosion puffing drying (AD+EPD).  Overall, FD+MVD can be used as a suitable drying method for the development of probiotic enriched apple snacks in consideration of colour, texture, sensory quality, bacterial viability and storage stability.  Probiotic bacteria in FD+MVD-dried samples remained above 1×10⁶ CFU g^–1 for 120 days at 25°C.  Interestingly, bacterial viability in FD+MVD-dried samples turned out to be significantly higher than FD-dried samples during storage for 120 days.  

    Porcine reproductive traits are characterized by low heritability, making improvement by traditional selective breeding rather difficult. Molecular breeding offers powerful approaches to overcome previous limitations and is expected to generate economic benefits via progress in pig breeding. Cytochrome P450 family 19 subfamily A polypeptide 1 (CYP19A1) gene is a key enzyme of estradiol biosynthesis that plays an important role in the establishment of gestation and maintenance of pregnancy. In this study, the sequence and structure characteristics of the porcine CYP19A1 gene was analyzed and expression patterns of CYP19A1 in different tissues of adult female pigs were detected. Fourteen single-nucleotide polymorphisms (SNPs) in the exons and introns of porcine CYP19A1 were identified and genotyped using the Sequenom MassARRAY platform, after which the allele frequency of each SNP was analyzed. The association between CYP19A1 SNPs and litter size and piglet birth weight was assessed in a crossbred pig population (n=375). The expression pattern of CYP19A1 revealed that it was highly expressed in the ovary, spleen, and uterus and lowly expressed in the other tissues. Moreover, one SNP, rs341891833, was significantly associated with piglet birth weight during the multiparity period (P<0.01). We concluded that CYP19A1 could be used as a candidate molecular marker in breeding aimed at rapid improvement of the reproductive characteristics of pigs.  

Sucrose is known to play an important role in the cryopreservation of sperm and female gonads; however, its effect on the cryopreservation of pig spermatogonial stem cells (pSSCs) has not been tested.  The aim of this work was to study the effect of sucrose during pSSC cryopreservation and to find the most effective concentration in freezing medium.  pSSCs were cryopreserved with freezing media containing different concentrations of sucrose (70, 140, 210, and 280 mmol L^–1) and a control group without sucrose.  The survival rates, plasma membrane integrity, and mitochondrial membrane potential of thawed cells were detected by trypan blue (TB) staining, SYBR-14/propidium iodide (PI) dual staining, and JC-1 staining, respectively.  All the staining results showed an obvious increase in cell survival in the sucrose-treated groups as compared to that in the control group, with the exception of 280 mmol L^–1 sucrose.  Moreover, the 210 mmol L^–1 sucrose group yielded the highest survival rate among all the groups (P<0.05).  The results of SYBR-14/PI dual staining and JC-1 staining were consistent with those of TB staining as above described.  Quantitative real-time PCR (qRT-PCR) indicated that the mRNA levels of three apoptosis-promoting genes (BAX, APAF1 and CASPASE9) were significantly higher in thawed cells than in cells before freezing (P<0.05).  Moreover, the mRNA level of one anti-apoptotic gene (XIAP) was significantly lower in thawed cells than in cells before freezing (P<0.05).  When comparing the mRNA expression of apoptosis-related genes in thawed cells, the mRNA level of the anti-apoptotic genes in the control group was significantly lower than that in the sucrose-treated
groups (P<0.05).  Western blot analyses showed that the expression levels of cleaved CASPASE9, CASPASE3 and PARP-1 in the sucrose-treated groups were lower than those in the control group and were the lowest in the 210 mmol L^–1 sucrose group.  Both qRT-PCR and Western blot analyses suggested that sucrose inhibited cell apoptosis during freezing and thawing.  Briefly, sucrose promoted pSSCs survival after freezing and thawing, especially at a concentration of 210 mmol L^–1, which possibly assisted pSSC dehydration and inhibited cell apoptosis.  These findings hold great promise for further studies of the regulatory mechanism of proliferation and differentiation of pSSCs. 

   Agro-ecological conditions associated with the spread and persistence of highly pathogenic avian influenza (HPAI) are not well understood, but the trade of live poultry is suspected to be a major pathway. Although market chains of live bird trade have been studied through indirect means including interviews and questionnaires, direct methods have not been used to identify movements of individual poultry. To bridge the knowledge gap on quantitative movement and transportation of poultry, we introduced a novel approach for applying telemetry to document domestic duck movements from source farms at Poyang Lake, China. We deployed recently developed transmitters that record Global Positioning System (GPS) locations and send them through the Groupe Spécial Mobile (GSM) cellular telephone system. For the first time, we were able to track individually marked ducks from 3 to 396 km from their origin to other farms, distribution facilities, or live bird markets. Our proof of concept test showed that the use of GPS-GSM transmitters may provide direct, quantitative information to document the movement of poultry and reveal their market chains. Our findings provide an initial indication of the complexity of source-market network connectivity and highlight the great potential for future telemetry studies in poultry network analyses.

A hydroponic study was conducted to determine the effects of selenium (Se: 0, 3, 6 μmol L−1) on senescence-related oxidative stress in garlic plants grown under two sulfur (S) levels. We evaluated the yields of plants harvested at 160 and 200 days after sowing. Plants grown under a low Se dose (0.3 μmol L−1) at low S level showed higher yields (12.0% increase in fresh weight yield, 13.7% increase in dry weight yield) than the controls, despite a decrease in chlorophyll concentration. Compared with control plants, the Se-treated plants showed lower levels of lipid peroxidation. The Se-treated plants also showed higher activities of glutathione peroxidase and catalase, but lower superoxide dismutase activities. Changes in Fv/Fm values and proline contents were affected more strongly by S than by Se. On the basis of our results, we can conclude that Se plays a key role in the antioxidant systems in garlic seedlings. It delays senescence by alleviating the peroxide stress, but it can be toxic at high levels. A high S level may increase tolerance to high Se concentrations through reducing Se accumulation in plants.

Soil erosion on cropland is a major source of environmental problems in China ranging from the losses of a non-renewable resource and of nutrients at the source to contamination of downstream areas. Regional soil loss assessments using the Universal Soil Loss Equation (USLE) would supply a scientific basis for soil conservation planning. However, a lack of information on the cover and management (C) factor for cropland, one of the most important factors in the USLE, has limited accurate regional assessments in China due to the large number of crops grown and their complicated rotation systems. In this study, single crop soil loss ratios (SLRs) were collected and quantified for 10 primary crops from past studies or reports. The mean annual C values for 88 crop rotation systems in 12 cropping system regions were estimated based on the combined effects of single crop SLRs and the percentage of annual rainfall erosivity (R) during the corresponding periods for each system. The C values in different cropping system regions were compared and discussed. The results indicated that the SLRs of the 10 primary crops ranged from 0.15 to 0.74. The mean annual C value for all 88 crop rotation systems was 0.34, with a standard deviation of 0.12. The mean C values in the single, double and triple cropping zones were 0.37, 0.36 and 0.28, respectively, and the C value in the triple zone was significantly different from those in single and double zones. The C values of dryland crop systems exhibited significant differences in the single and triple cropping system regions but the differences in the double regions were not significant. This study is the first report of the C values of crop rotation systems in China at the national scale. It will provide necessary and practical parameters for accurately assessing regional soil losses from cropland to guide soil conservation plans and to optimize crop rotation systems.

With consecutive occurrences of drought disasters in China in recent years, it is important to estimate their potential impacts on regional crop production. In this study, we detect the impacts of drought on wheat and maize yield and their changes at a 0.5°×0.5° grid scale in the wheat-maize rotation planting area in the North China Plain under the A1B climate change scenario using the Decision Support System for Agrotechnology Transfer (DSSAT) model and the outputs of the regional climate modeling system - Providing Regional Climates for Impacts Studies (PRECIS). Self-calibrating palmer drought severity index was used as drought recognition indicator. Two time slices used for the study were the baseline (1961-1990) and 40 years of 2011-2050. The results indicate that the potential planting region for double crop system of wheat-maize would expend northward. The statistic conclusions of crop simulations varied considerably between wheat and maize. In disaster-affected seasons, wheat yield would increase in the future compared with baseline yields, whereas in opposite for maize yield. Potential crop yield reductions caused by drought would be lower for wheat and higher for maize, with a similar trend found for the ratio of potential crop yield reductions for both crops. It appears that the negative impact of drought on maize was larger than that on wheat under climate change A1B scenario.

Brassica campestris male fertility 19 (BcMF19; GenBank accession number GQ902048.1), a gene that is specially expressed in tapetum cells and microspores during anther development in B. campestris ssp. chinensis, which is learned from the previous in situ hybridization study. In the present study, we constructed antisense-silenced plants of BcMF19 using B. campestris ssp. chinensis to validate this prediction. The morphology of the pistils, long anthers, and short anthers was significantly affected in 35sbcmf19 compared with the control samples. 4´-6-Diamidino-2-phenylindole staining revealed that two generative nuclei and one large vegetative nucleus were not affected in the mutant compared with control. Statistical analysis of Alexander’s staining results showed that 96% of the control pollen grains had vitality, whereas only 86% of the mutant pollen grains did. Under scanning electron microscopy, the mutant demonstrated numerous abnormal pollen grains and resembled dried persimmon. The frequency of normal pollen grains was approximately 18%. Under transmission electron microscopy, the pollen intine during the binucleate and mature pollen stages in 35sbcmf19 exhibited abnormal thickening, especially at the germinal furrows, compared with control. In vitro pollen germination test showed that the tips of the mutant pollen tubes transformed into globular alveoli and stopped growing compared with control. On the other hand, in vivo pollen germination test suggested that BcMF19 affected the pollen tube extension in the pistil. These findings indicate that BcMF19 is essential to the pollen development and pollen tube extension of B. campestris ssp. chinensis.

Empirical research has shown that the use of manure significantly improves crop yield, soil fertility and water and moisture conservation. Despite these documented benefits, however, there is a concern on the downward trend of manure use in agriculture in China. This paper examines factors contributing to this downward trend, with a particular focus on human excreta used in agriculture. Empirical analysis based on data from stratified random sampling of rural households in five provinces of China shows that about 85% of human excreta was still used as manure in agriculture in 2007 which was less than a decade ago when nearly all human excreta was used as manure. Econometric results suggest that income growth, rising population density and improvement in rural transportation significantly contribute to declining use of human excreta as manure in agriculture. These results imply that the current downward trend will continue given China’s rising economic growth, urbanization and rural infrastructural improvement.

Invasion of the oriental fruit fly, Bactrocera dorsalis, into new niches containing different food sources (a process referred to as host shift), may cause population genetic differentiation and sympatric speciation. To attempt to infer that experimentally, test populations were established by transferring a subset of the original populations, which had been grown on banana for many generations, onto navel orange, and then subculturing the navel orange population and banana population for at least 20 generations. Four pairs of SSR primers with high polymorphism on laboratory strains were used to detect population genetic differentiation. All six tested populations (the 5th, 10th and 15th generations of B. dorsalis fed on banana and navel orange, respectively) were found to have low genetic diversity. Furthermore, the genetic diversity of the navel orange populations was found to decline after being crossed for several generations. Populations initially were deviated from Hardy-Weinberg equilibrium, however, equilibrium was achieved with increasing numbers of generations in both of the host populations. Limited gene flows were found among the six populations. The Nei’s standard genetic distances between the two host populations of the same generation were initially low, but increased with generation number. Genetic distances between banana and navel orange populations of the same generation were lower than genetic distances between different generations grown on the same host plant. Analysis of molecular distance (AMOVA) results based on generation groups and host groups demonstrated that genetic variation among generations was greater than that between the two host populations. The results indicated that population genetic differentiation occurred after the host shift, albeit at low level. Biogeography and taxonomy of the B. dorsalis complex revealed that speciation of B. dorsalis might be tightly associated with host shift or host specialization of B. dorsalis following dispersal.

Natural herbicides, or environment-friendly bioherbicides have been attracted more and more attentions. Isolation and structural identification of natural herbicide-active compounds from plant pathogens has been proved to be an effective approach for novel lead discovery of the pesticide development. In this study, the metabolites of the mutant strain PAM1, which obtained from PA1 of Pythium aphanidermatum (Eds.) Fitzp by ultraviolet radiation were separated and identified by HPLC, NMR, and IR. The results revealed that three active compounds including 4-hydroxy-3-methoxycinnamic acid and two indole derivatives, exhibited inhibition activity on the elongation of radical and coleoptile of Digtaria sanguinalis (L.) Scop.

The present study was carried out to investigate the pharmacokinetics of mequindox (MEQ), a new synthetic quinoxaline 1,4-dioxide derivative and its two main metabolites M1 [2-isoethanol mequinoox], M2 [2-isoethanol 1-desoxymequindox] in healthy swine. MEQ (10 mg kg-1 body weight) was administered to nine healthy cross-bread swine via oral, intramuscular, and intravenous routes in a randomized 3×3 crossover design with a 1-wk washout period. A sensitive high-performance liquid chromatography (HPLC) method was used for the determination of plasma concentrations of MEQ and its metabolites M1 and M2. Plasma concentration versus time profiles of MEQ and its metabolites, M1 and M2, were analyzed by noncompartmental analysis using WinNonlin 5.2 software. The mean maximum concentrations (Cmax) of M1 and M2 after intravenous administration of MEQ were (5.27±1.59) μg mL-1 at 1.78 h and (1.01±0.29) μg mL-1 at 0.92 h, respectively. The mean maximum concentrations (Cmax) of MEQ, M1, and M2 were found to be (6.96±3.23), (6.61±1.56), and (0.78 ±0.25) μg mL-1, respectively at 0.15, 1.61, and 1.30 h after intramuscular administration of MEQ, respectively and (0.75±0.45), (6.90±1.52), and (0.62±0.21) μg mL-1, respectively at 0.40, 1.57, and 2.00 h, respectively after oral administration of MEQ. The apparent elimination half-lives (t1/2) of MEQ, M1, and M2 were (0.84±0.35), (7.57±3.93), and (9.56±6.00) h, respectively after intravenous administration of MEQ; (0.50±0.25), (6.30±3.00), and (5.94±2.54) h, respectively after intramuscular administration of MEQ; and (1.64±1.17), (5.59±1.93), and (16.25±10.27) h , respectively after oral administration of MEQ. The mean areas under the plasma concentration-time curve (AUC0- ) of MEQ, M1, and M2 were (4.88±1.54), (36.93±17.50), and (5.16±1.94) μg h mL-1, respectively after intravenous administration of MEQ; (4.18±0.76), (48.25±20.82), and (4.88±2.21) μg h mL-1 , respectively after intramuscular administration of MEQ; and (1.01±0.40), (48.83±20.71), and (5.54±2.23) μg h mL-1, respectively after oral administration of MEQ. MEQ was rapidly absorbed and metabolized in swine after oral, intramuscular, and intravenous administration. Further studies are required to investigate the double-peak phenomenon observed in the plasma concentration-time profile after oral administration and the pharmacokinetics of other metabolites of MEQ.