In mammals, microRNAs (miRNAs) play key roles in multiple biological processes by regulating the expression of target genes.  Studies have found that the levels of miR-370-5p expression differ significantly in the skins of sheep with different hair colors; however, its function remains unclear.  In this study, we investigated the roles of miR-370-5p in sheep melanocytes and found that the overexpression of miR-370-5p significantly inhibited cell proliferation (P<0.01), tyrosinase activity (P=0.001) and significantly reduced (P<0.001) melanin production.  Functional prediction revealed that the 3´-untranslated region (UTR) of MAP3K8 has a putative miR-370-5p binding site, and the interaction between these two molecules was confirmed using luciferase reporter assays.  In situ hybridization assays revealed that MAP3K8 is expressed in the cytoplasm of melanocytes.  The results of quantitative RT-PCR and Western blotting analyses revealed that overexpression of miR-370-5p in melanocytes significantly inhibits (P<0.01) MAP3K8 expression via direct targeting of its 3´ UTR.  Inhibition of MAP3K8 expression by siRNA-MAP3K8 transfection induced a significant inhibition (P<0.01) of melanocyte proliferation and significant reduction (P<0.001) in melanin production, which is consistent with our observations for miR-370-5p.  Target gene rescue experiments indicated that the expression of MAP3K8 in melanocytes co-transfected with miR-370-5p and MAP3K8-cDNA (containing sites for the targeted binding to miR-370-5p) was significantly rescued (P≤0.001), which subsequently promoted significant increases in cell proliferation (P<0.001) and melanin production (P<0.01).  Collectively, these findings indicate that miR-370-5p plays a functional role in inhibiting sheep melanocyte proliferation and melanogenesis by downregulating the expression of MAP3K8.  

Plant height is a key plant architectural trait that affects the seed yield, harvest index and lodging resistance in Brassica napus L., although the genetic mechanisms affecting plant height remain unclear.  Here, a semi-dwarf mutant, df34, was obtained by ethyl methanesulphonate-induced mutagenesis.  Genetic analysis showed that the semi-dwarf phenotype is controlled by one semi-dominant gene, which was located on chromosome C03 using a bulked segregant analysis coupled with whole-genome sequencing, and this gene was named BnaSD.C3.  Then BnaSD.C3 was fine-mapped to a 297.35-kb segment of the “Darmor-bzh” genome, but there was no potential candidate gene for the semi-dwarf trait underlying this interval.  Furthermore, the interval was aligned to the Zhongshuang 11 reference genome.  Finally, combining structural variation analysis, transcriptome sequencing, phytohormone analyses and gene annotation information, BnaC03G0466900ZS and BnaC03G0478900ZS were determined to be the most likely candidate genes affecting the plant height of df34.  This study provides a novel major locus for breeding and new insights into the genetic architecture of plant height in B. napus

Utilizing the heterosis of indica/japonica hybrid rice (IJHR) is an effective way to further increase rice grain yield.  Rational application of nitrogen (N) fertilizer plays a very important role in using the heterosis of IJHR to achieve its great yield potential.  However, the responses of the grain yield and N utilization of IJHR to N application rates and the underlying physiological mechanism remain elusive.  The purpose of this study was to clarify these issues.  Three rice cultivars currently used in rice production, an IJHR cultivar Yongyou 2640 (YY2640), a japonica cultivar Lianjing 7 (LJ-7) and an indica cultivar Yangdao 6 (YD-6), were grown in the field with six N rates (0, 100, 200, 300, 400, and 500 kg ha^–1) in 2018 and 2019.  The results showed that with the increase in N application rates, the grain yield of each test cultivar increased at first and then decreased, and the highest grain yield was at the N rate of 400 kg ha^–1 for YY2640, with a grain yield of 13.4 t ha^–1, and at 300 kg ha^–1 for LJ-7 and YD-6, with grain yields of 9.4–10.6 t ha^–1.  The grain yield and N use efficiency (NUE) of YY2640 were higher than those of LJ-7 or YD-6 at the same N rate, especially at the higher N rates.  When compared with LJ-7 or YD-6, YY2640 exhibited better physiological traits, including greater root oxidation activity and leaf photosynthetic rate, higher cytokinin content in the roots and leaves, and more remobilization of assimilates from the stem to the grain during grain filling.  The results suggest that IJHR could attain both higher grain yield and higher NUE than inbred rice at either low or high N application rates.  Improved shoot and root traits of the IJHR contribute to its higher grain yield and NUE, and a higher content of cytokinins in the IJHR plants plays a vital role in their responses to N application rates and also benefits other physiological processes. 

Investigating the dynamics and distribution of soil phosphorus (P) fractions can provide a basis for enhancing P utilization by crops.  Four treatments from a 29-year long-term experiment in black soil with maize cropping were involved in this study: no fertilizer (CK), inorganic nitrogen and potassium (NK), inorganic nitrogen, phosphorus, and potassium (NPK), and NPK plus manure (NPKM).  We analyzed soil P fractions in different soil layers using a modified Hedley sequential method.  The long-term NPKM treatment significantly increased total P by 0.6–1.6 times in the different soil layers.  The Olsen-P concentration far exceeded the environmental threshold for soil Olsen-P (50.6 mg kg^–1) in the NPKM treatment in the 0–60 cm soil profile.  Moreover, the concentrations and proportion of labile and partially labile inorganic P (Pi) fractions (i.e., NaHCO₃-extracted Pi, NaOH-extracted Pi, and dilute HCl-extracted Pi) to the sum of all P fractions (Pt) in the 0–60 cm soil profile were higher in the NPKM treatment than in the NPK treatment, indicating that manure could promote the transformation of non-labile into more labile forms of P in soil, possibly by manure reducing P fixation by soil particles.  Soil organic matter, Mehlich-3 extractable iron (Fe), and organic-bound aluminum were increased by fertilization, and were the main factors influencing the differences in the P fractions in the 0–20 cm soil layer.  Soil mineral components, i.e., free Fe oxide and CaCO₃, were the main factors influencing the P fractions in the subsoil.  The soil P transformation process varied with soil layer and fertilization.  Application of manure fertilizer can increase the labile (Olsen) P concentrations of the various soil layers, and thus should reduce the mineral P fertilizer requirement for crop growth and reduce potential environmental damage

Genetic diversity, population structure, and population expansion of goats worldwide (4 165 individuals from 196 breeds) were analyzed using published mitochondrial DNA (mtDNA) D_loop hypervariable region sequences. Results showed that 2 409 haplotypes and 301 polymorphic sites were present within the 401-bp length D_loop region, the nucleotide diversity (Pi) was 0.03471, and the haplotype diversity (Hd) was 0.9983. Phylogenetic analysis revealed that 98.92% of haplotypes were divided into six obvious clusters, consistent with the classification of the known mitochondrial haplogroups of goats. Haplogroup A accounted for the largest proportion (86%). Interestingly, two unknown divisions (Unknown I and Unknown II) were discovered from goats in Southwest China, suggesting that Southwest China has unique maternal haplogroups. Analysis of molecular variance (AMOVA) and the average number of pairwise differences between populations (PiXY) indicated that geographical variation was small but significant. Neutrality tests (Tajima’s D and Fu’s F_S tests) and mismatch distribution showed that haplogroups B, C, and G had expansion histories. In addition, the phylogenetic relationship between domestic and wild goats suggested that Capra aegagrus is the most likely wild ancestor and may have participated in the domestication of ancestral populations of A, B, C, and F haplogroups. A meta-analysis on the mtDNA sequences of goats from international databases was conducted to analyze goats’ genetic diversity, population structure, and matrilineal system evolution worldwide. The results may help further understand the domestication history and gene flow of goats worldwide.

Excessive use of nitrogen fertilizer in China and its adverse effects on agricultural production have been a national and global concern. In addition to massive public initiatives to promote sustainable farm practices, grass-rooted innovations are emerging in the niche, many of which take the forms of information and communication technologies (ICT) and digital services. This study examines the effects of ICT-based extension services provided by an entrepreneurial startup on adopting sustainable farming practices. We found no significant reduction in N-fertilizer use for wheat production. But the ICT-based services promoted farmers to adapt N-fertilizer use towards site-specific management. The business model of the entrepreneurial venture faces great challenges in becoming participatory and financially sustainable.

The use of nitrogen (N)-efficient rice (Oryza sativa L.) varieties could reduce excessive N input without sacrificing yields. However, the plant traits associated with N-efficient rice varieties have not been fully defined or comprehensively explored.  Here, three japonica N-efficient varieties (NEVs) and three japonica N-inefficient varieties (NIVs) of rice were grown in a paddy field under N omission (0 N, 0 kg N ha^–1) and normal N (NN, 180 or 200 kg N ha⁻¹) treatments.  Results showed that NEVs exhibited higher grain yield and nitrogen use efficiency (NUE) than NIVs under both treatments, due to improved sink size and filled-grains percentage in the former which had higher root oxidation activity and greater root dry weight, root length and root diameter at panicle initiation (PI), as well as higher spikelet–leaf ratio and more productive tillers during the grain-filling stage.  Compared with NIVs, NEVs also exhibited enhanced N translocation and dry matter accumulation after heading and improved flag leaf morpho–physiological traits, including greater leaf thickness and specific leaf weight and higher contents of ribulose-1,5-bisphosphate carboxylase/oxygenase, chlorophyll, nitrogen, and soluble sugars, leading to better photosynthetic performance.  Additionally, NEVs had a better canopy structure, as reflected by a higher ratio of the extinction coefficient for effective leaf N to the light extinction coefficient, leading to enhanced canopy photosynthesis and dry matter accumulation.  These improved agronomic and physiological traits were positively and significantly correlated with grain yield and internal NUE, which could be used to select and breed N-efficient rice varieties.

Grapevine (Vitis vinifera L.) is an economically important fruit crop in the world, and China ranks first in the production of grapes with approximately 15% of the world’s total yield.  However, diseases that cause the death of grapevine shoots pose a severe threat to the production of grapes.  In this study, the fungus Neopestalotiopsis eucalypti was identified as a causal pathogen of grapevine shoot rot based on the morphology of conidia and a phylogenetic analysis.  The phylogenetic analysis was performed with three isolates based on the combined sequence of internal transcribed spacer (ITS) region of ribosomal DNA, part of the translation elongation factor 1-alpha (Tef) and the β-tubulin (Tub2) genes.  The three isolates were all identified as N. eucalypti.  Pathogenicity tests of the three fungal isolates were conducted on grapevines shoots in vitro and in vivo.  The results showed that all three fungal isolates caused severe rot lesions on the inoculated grapevine shoots, and N. eucalypti was re-isolated from the inoculated grapevine shoots.  Therefore, N. eucalypti was confirmed as a causal agent of the grapevine shoot rot.  This is the first report of N. eucalypti causing grapevine shoot disease in China.

Salinity threatens soybean germination, growth and production.  The germination stage is a key period in the life of soybean.  Wild soybean contains many genes related to stress resistance that are valuable resources for the genetic improvement of soybean.  To identify the genetic loci of wild soybean that are active during seed germination under salt stress, two populations, a soybean interspecific hybrid population comprising 142 lines and a natural population comprising 121 wild soybean accessions, were screened for three germination-related traits in this study.  By using single-nucleotide polymorphism (SNP) markers with three salt tolerance indices, 25 quantitative trait loci (QTLs), 21 significant SNPs (–log₁₀(P)≥4.0) and 24 potential SNPs (3.5<–log₁₀(P)<4.0) were detected by linkage mapping and a genome-wide association study (GWAS) in two environments.  The key genetic region was identified based on these SNPs and QTLs.  According to the gene functional annotations of the W05 genome and salt-induced gene expression qRT-PCR analysis, GsAKR1 was selected as a candidate gene that responded to salt stress at the germination stage in the wild soybean.  These results could contribute to determining the genetic networks of salt tolerance in wild soybean and will be helpful for molecular marker-assisted selection in the breeding of salt-tolerant soybean.

In 2009, an emerging citrus viral disease caused by Citrus chlorotic dwarf-associated virus (CCDaV) was discovered in Yunnan Province of China.  However, the occurrence and spread of CCDaV in other citrus-growing provinces in China is unknown to date.  To better understand the distribution and molecular diversity of CCDaV in China, a total of 1 772 citrus samples were collected from 11 major citrus-growing provinces and were tested for CCDaV by PCR.  Among these, 134 citrus samples from Guangxi, Yunnan and Guangdong were tested positive for CCDaV, demonstrating that the occurrence and spread of CCDaV are increasing in China.  The complete genome sequences of 17 CCDaV isolates from different provinces and hosts were sequenced.  Comparisons of the whole-genome sequences of the 17 CCDaV isolates as well as the 15 isolates available in GenBank revealed that the sequence identity was about 99–100%, showing that the CCDaV isolates were highly conserved.  Phylogenetic studies showed that the 32 CCDaV isolates belonged to four different groups based on geographical origins and host species, and that CCDaV isolates from China and Turkey were clustered into different groups.  The results provide important information for clarifying the distribution and genetic diversity of CCDaV in China.

The concentration of soil Olsen-P is rapidly increasing in many parts of China, where P budget (P input minus P output) is the main factor influencing soil Olsen-P.  Understanding the relationship between soil Olsen-P and P budget is useful in estimating soil Olsen-P content and conducting P management strategies.  To address this, a long-term experiment (1991–2011) was performed on a fluvo-aquic soil in Beijing, China, where seven fertilization treatments were used to study the response of soil Olsen-P to P budget.  The results showed that the relationship between the decrease in soil Olsen-P and P deficit could be simulated by a simple linear model.  In treatments without P fertilization (CK, N, and NK), soil Olsen-P decreased by 2.4, 1.9, and 1.4 mg kg^–1 for every 100 kg ha^–1 of P deficit, respectively.  Under conditions of P addition, the relationship between the increase in soil Olsen-P and P surplus could be divided into two stages.  When P surplus was lower than the range of 729–884 kg ha^–1, soil Olsen-P fluctuated over the course of the experimental period with chemical fertilizers (NP and NPK), and increased by 5.0 and 2.0 mg kg^–1, respectively, when treated with chemical fertilizers combined with manure (NPKM and 1.5NPKM) for every 100 kg ha^–1 of P surplus.  When P surplus was higher than the range of 729–884 kg ha^–1, soil Olsen-P increased by 49.0 and 37.0 mg kg^–1 in NPKM and 1.5NPKM treatments, respectively, for every 100 kg ha^–1 P surplus.  The relationship between the increase in soil Olsen-P and P surplus could be simulated by two-segment linear models.  The cumulative P budget at the turning point was defined as the “storage threshold” of a fluvo-aquic soil in Beijing, and the storage thresholds under NPKM and 1.5NPKM were 729 and 884 kg ha^–1 P for more adsorption sites.  According to the critical soil P values (CPVs) and the relationship between soil Olsen-P and P budget, the quantity of P fertilizers for winter wheat could be increased and that of summer maize could be decreased based on the results of treatments in chemical fertilization.  Additionally, when chemical fertilizers are combined with manures (NPKM and 1.5NPKM), it could take approximately 9–11 years for soil Olsen-P to decrease to the critical soil P values of crops grown in the absence of P fertilizer. 

Global demand for soil data and information for maintaining and improving agricultural productivity and environmental health is soaring.  The accurate and rapid digital maps of soil characteristics are of key importance for evaluation of soil fertility, precision management of crop inputs, estimation of carbon stocks, and modeling ecological responses as well as environmental threats.  

The progress in digital soil mapping (DSM) over the last decade provided an improved choice to monitor and map soil characteristics in space and time.  Previous reviews have discussed the history (McBratney et al. 2003; Hartemink et al. 2013; Minasny and McBratney 2016) and the progress in DSM in general (Grunwald et al. 2011; Zhang et al. 2017).  However, the field of DSM has been moving at an accelerated pace and the progress has been observed in all aspects including data organization and quality, soil sampling, environmental covariates, predictive models, and map validation.  In this special issue, the selected eight papers document some of the scopes, developments and progresses in digital mapping in agriculture and environment.

First four papers documented the progress and developments in predictive models.  Teng et al. (2019) used new methodologies including Collocated CoKriging (ColCOK), geographically weighted regression (GWR) and Random Forest (RF) regression to integrate satellite images, field samples, and ground observations to map the soil loss potential in China.  Cheng et al. (2019) proposed a method of mining soil–environmental relationships from individual soil polygons to update conventional soil maps of the Raffelson watershed in La Crosse County, Wisconsin, United States.  Gao et al. (2019) predicted the spatial variability of soil total nitrogen (TN), total phosphorus (TP) and total potassium (TK) using geostatistical analysis and regression analysis.  Li et al. (2019) evaluated the spatial variability of soil bulk density and its controlling factors at different soil layers in Southwest China’s agricultural intensive area.

The following three papers documented the progress in environmental covariate selection, processing and utilization.  Lu et al. (2019) proposed a framework integrating Pearson correlation analysis, generalized additive models (GAMs), and Random Forest (RF) to select environmental covariates for predictive soil depth mapping in the upper reaches of the Heihe River Basin in Northwest China.  Wu et al. (2019) used the combination of surface albedo computed from moderate resolution imaging spectroradiometer (MODIS) reflectance products and the actual measured soil moisture data to map an albedo/vegetation coverage trapezoid feature space.  Wang et al. (2019) applied natural language processing (NLP) and rule-based techniques to automatically extract and structure information from soil survey reports regarding soil–environment relationships.

The last paper talked about soil sampling.  Guo et al. (2019) employed EM38 data to estimate the spatio-temporal variation of soil salinity in different site-specific management zones.  Fuzzy-k means algorithm was used to divide the site-specific management zones and to help sampling design.  

We believe that the reader both in China and abroad will be interested in these articles and be inspired with the finding of the papers for developing future research on digital mapping in agriculture and environment.  We want to express our deepest appreciation to all the authors for their high-quality contributions and efforts to make this special issue a great success.

Rapeseed is a very important oil crop in China; however, its production is challenging due to the absence of effective weed management strategies.  This is predominantly because of a shortage of herbicide resistance genes.  Acetohydroxyacid synthase (AHAS) herbicides inhibit AHAS, a key enzyme involved in branched-chain amino acid synthesis that is required for plant growth.  A rapeseed line designated M342 with AHAS herbicide resistance was developed through seed mutagenesis and was studied to assess the level and mode of inheritance of the resistance and to identify the molecular basis of resistance.  M342 possessed a high level of cross-resistance to sulfonylureas (SUs) and imidazolinones (IMIs).  This resistance was due to AHAS insensitivity to these herbicides and was inherited as a dominant trait conferred by a single nuclear-encoded gene.  Molecular analysis revealed the presence of a Trp574Leu mutation in M342, and an allele-specific cleaved amplified polymorphic sequence (AS-CAPS) marker was developed and cosegregated with herbicide resistance in the F₂, BC₁, and BC₂ populations.  This mutation altered the transcript levels of BnAHAS1 and BnAHAS3 in M342 compared with those in the wild type, but it did not affect the agronomic or quality traits.  The simple genetic inheritance of this mutation and the availability of the cleaved amplified polymorphic sequence (CAPS) marker and herbicide resistance gene should facilitate the development of herbicide-resistant rapeseed cultivars for effective weed control in China.  

A total of 900 one-d-old Chinese Huainan Partridge Shank chickens were randomly allocated into nine groups with five replicates of 20 each.  Birds were fed with basal diet, basal diet supplemented with 150 mg kg^–1 aureomycin, basal diet supplemented with different proportions of Bacillus licheniformis and Bacillus subtilis, which was 0:1.0×10⁶, 2.5×10⁵:7.5×10⁵, 3.3×10⁵:6.6×10⁵, 5.0×10⁵:5.0×10⁵, 6.6×10⁵:3.3×10⁵, 7.5×10⁵:2.5×10⁵ and 1.0×10⁶:0, respectively.  The duration of the experiment was 56 d.  The results indicated that dietary supplementation of 6.6×10⁵:3.3×10⁵ of B. lichenifornis:B. subtilis improved final body weight, increased the average daily gain, and reduced feed/gain ratio (P<0.05).  The numbers of total Lactobacillus and Bifidobacterium sp. in the caecum significantly increased, and the numbers of Escherichia coli and Salmonella sp. significantly declined compared to that of the control (P<0.05).  Intestinal villous height and villous height to crypt depth ratio of the duodenum, jejunum, and ileum were significantly higher than that of the control, and intestinal crypt depth of the duodenum and ileum was significantly lower (P<0.05).  The total antioxidant capacity, total superoxide dismutase, and glutathione peroxidase ability in plasma significantly improved, while the malondialdehyde concentration in plasma decreased (P<0.05).  Compared to the control, plasma concentrations of ammonia, uric acid and urea nitrogen and the activity of xanthine oxidase were reduced (P<0.05).  In conclusion, an inclusion of 6.6×10⁵:3.3×10⁵ of B. licheniformis: B. subtilis to the diet improved the growth performance, caecal microbiota, plasma biochemical profile, and significantly improved the small intestine morphology, while reducing the mortality rate. 

The additions of straw and biochar have been suggested to increase soil fertility, carbon sequestration, and crop productivity of agricultural lands.  To our knowledge, there is little information on the effects of straw and biochar addition on soil nitrogen form, carbon storage, and super rice yield in cold waterlogged paddy soils.  We performed field trials with four treatments including conventional fertilization system (CK), straw amendment 6 t ha^–1 (S), biochar amendment 2 t ha^–1 (C1), and biochar amendment 40 t ha^–1 (C2).  The super japonica rice variety, Shennong 265, was selected as the test crop.  The results showed that the straw and biochar amendments improved total nitrogen and organic carbon content of the soil, reduced N₂O emissions, and had little influence on nitrogen retention, nitrogen density, and CO₂ emissions.  The S and C1 increased NH₄⁺-N content, and C2 increased NO₃^–-N content.  Both S and C1 had little influence on soil organic carbon density (SOCD) and C/N ratio.  However, C2 greatly increased SOCD and C/N ratio.  C1 and C2 significantly improved the soil carbon sequestration (SCS) by 62.9 and 214.0% (P<0.05), respectively, while S had no influence on SCS.  C1 and C2 maintained the stability of super rice yield, and significantly reduced CH₄ emissions, global warming potential (GWP), and greenhouse gas intensity (GHGI), whereas S had the opposite and negative effects.  In summary, the biochar amendments in cold waterlogged paddy soils of North China increased soil nitrogen and carbon content, improved soil carbon sequestration, and reduced GHG emission without affecting the yield of super rice.

   The proline transporter protein (ProT) plays an important role in protective stress responses in various plants. However, its function in abiotic stress responses in soybean (Glycine max) remains obscure. In the present study, two soybean ProT genes, namely GmProT1 and GmProT2, were isolated by homologous cloning. GmProT1 and GmProT2 encode polypeptides of 435 and 433 amino acids, respectively. The GmProT1 and GmProT2 proteins showed high similarity to other ProT proteins. GmProT1 and GmProT2 transcripts were detected in different soybean tissues including roots, stems, leaves, flowers, and developmental seeds, and during diverse developmental stages. GmProT1 was strongly expressed in seeds 35 days after flowering. Quantitative real-time PCR analysis showed that the two genes were highly expressed in leaves and could be strongly induced in response to salt and drought conditions and ABA treatment. Transgenic Arabidopsis thaliana plants overexpressing the two genes were generated, which showed that GmProT genes attenuate damage from salt and drought stress. In addition, transgenic Arabidopsis plants accumulated proline in response to salt and osmotic stress. Transcription levels of salinity-responsive gene (RD29B and S0S3) and drought-induced gene (CDPK1) were higher in the transgenic lines than that of wild type plants. Our work provides evidence that GmProT genes function in the response to abiotic stresses and may affect the synthesis and response system of proline.

China is the largest potato producing country worldwide, with this crop representing the fourth largest staple food crop in China. However, the steady presence of Potato spindle tuber viroid (PSTVd) over the past five decades has a significant economic impact on potato production. To determine why PSTVd control measures have been ineffective in China, more than 1 000 seed potatoes collected between 2009 and 2014 were subjected to PSTVd detection at the Supervision and Testing Center for Virus-free Seed Potatoes Quality, Ministry of Agriculture, China. A high PSTVd infection rate (6.5%) was detected among these commercial seed potatoes. Some breeding lines of potato collected from 2012 to 2015 were also tested for PSTVd infection, revealing a high rate of PSTVd contamination in these potato propagation materials. Furthermore, comparison of the full-length sequences of 71 different Chinese PSTVd isolates revealed a total of 74 predominant PSTVd variants, which represented 42 different sequence variants of PSTVd. Comparative sequence analysis revealed 30 novel PSTVd sequence variants specific to China. Comprehensive phylogenetic analysis uncovered a close relationship between the Chinese PSTVd sequence variants and those isolated from Russia. It is worth noting that three intermediate strains and six mild strains were identified among these variants. These results have important implications for explaining the ineffective control of PSTVd in China and thus could serve as a basic reference for designing more effective measures to eliminate PSTVd from China in the future.

    CD8, a glycoprotein on the surface of T cells, is involved in the defense against viral infection and plays significant roles in antigen presentation and in the antiviral immune response. CD8 is composed of two chains. Of these, the CD8α chain was chosen for the detection because it involved in both the CD8αα homodimer and the CD8αβ heterodimer. Here, we established a double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for specific detection of goose CD8α (goCD8α). The results showed that the optimal coated antibody and antigen dilutions were 1:50 (the antibody titer was 1:12 800) and 1:32 (0.3 ng mL^–1), respectively, while the optimal capture antibody and horseradish peroxidase (HRP)-labelled goat anti-rabbit IgG dilutions were 1:50 (the antibody titer was 1:51 200) and 1:4 000 (the antibody titer was 1:5 000), respectively. The optimal blocking buffer was 5% bovine serum albumin (BSA). The best incubating condition was overnight at 4°C, the best blocking time was 120 min and the best anti-capture antibody working time was 150 min. In addition, the minimum dose detectable by DAS-ELISA was 5×10–3 ng mL^–1. Most importantly, goCD8α expression levels in goose spleen mononuclear cells (MNCs) post-Goose parvoviruse (GPV) infection were found to be significantly up-regulated using the DAS-ELISA method, which was consistent with previous results obtained using real-time quantitative PCR. In conclusion, the DAS-ELISA method reported here is a novel, specific technique for the clinical detection of goCD8α.

The SQUAMOSA promoter binding protein (SBP)-box genes encode a kind of plant-specific transcription factors (TFs) and play important roles in the regulation of plant development. In this study, a genome-wide characterization of this family was conducted in maize (Zea mays). Thirty-one SBP-box genes were identified to be distributed in nine chromosomes and 16 of them were complementary to the mature ZmmiR156 sequences. All the Z. mays SBP (ZmSBP) genes were classified into two clusters with eight subgroups according to the phylogenetic analysis of proteins, which were consistent with the pattern of exon-intron structures. The phylogenetic tree of the ZmSBP, Oryza sativa SBP-like (OsSPL) and Arabidopsis thaliana SBP-like (AtSPL) genes were constructed and all the SBP-box genes were divided into eight groups, which was the same as the classification of ZmSBP genes. The comparision of the expression profiles of all SBP-box genes in these three species indicated that most orthologous genes had similar expression patterns. The results from this study provided a basic understanding of the ZmSBP genes and might facilitate future researches for elucidating the SBP-box genes function in maize.

Increasing attentions have been paid to mineral concentration decrease in milled rice grains caused by CO2 enrichment, but the mechanisms still remain unclear. Therefore, mineral (Ca, Mg, Fe, Zn and Mn) translocation in plant-soil system with a FACE (Free-air CO2 enrichment) experiment were investigated in Eastern China after 4-yr operation. Results mainly showed that: (1) elevated CO2 significantly increased the biomass of stem and panicle by 21.9 and 24.0%, respectively, but did not affect the leaf biomass. (2) Elevated CO2 significantly increased the contents of Ca, Mg, Fe, Zn, and Mn in panicle by 61.2, 28.9, 87.0, 36.7, and 66.0%, respectively, and in stem by 13.2, 21.3, 47.2, 91.8, and 25.2%, respectively, but did not affect them in leaf. (3) Elevated CO2 had positive effects on the weight ratio of mineral/biomass in stem and panicle. Our results suggest that elevated CO2 can favor the translocation of Ca, Mg, Fe, Zn, and Mn from soil to stem and panicle. The CO2-led mineral decline in milled rice grains may mainly attribute to the CO2-led unbalanced stimulations on the translocations of minerals and carbohydrates from vegetative parts (e.g., leaf, stem, branch and husk) to the grains.

The regeneration rate of wheat immature embryo varies among genotypes, howbeit many elite agriculture wheat varieties have low regeneration rates. Optimization of tissue culture conditions and attempts of adding signal molecules are effective ways to increase plant regeneration rate. Inter-culture is one of ways that have not been investigated in plant tissue culture. Moreover, the use of arabinogalactan proteins (AGPs) and hydrogen peroxide (H2O2) have been reported to increase regeneration rate in a few plant species other than wheat. The current research pioneeringly uses inter-culture of immature embryos of different wheat genotypes, and also investigates impacts of AGP and H2O2 on the induction of embryogenic calli and plant regeneration. As a result, high-frequency regeneration wheat cultivars Kenong 199 (KN199) and Xinchun 9 (XC9), together with low-frequency regeneration wheat line Chinese Spring (CS), presented striking increase in the induction of embryogenic calli and plant regeneration rate of CS through inter-culture strategy, up to 52.19 and 67.98%, respectively. Adding 50 to 200 mg L–1 AGP or 0.005 to 0.01 ‰ H2O2 to the callus induction medium, enhanced growth of embryogenic calli and plant regeneration rate in quite a few wheat genotypes. At 50 mg L–1 AGP application level in callus induction medium plant regeneration rates of 8.49, 409.06 and 283.16% were achieved for Jimai 22 (JM22), Jingdong 18 (JD18) and Yangmai 18 (YM18), respectively; whereas at 100 mg L–1 AGP level, CS (105.44%), Chuannong 16 (CN16) (80.60%) and Ningchun 4 (NC4) (62.87%) acted the best. Moreover CS (79.05%), JM22 (7.55%), CN16 (101.87%), YM18 (365.56%), Yangmai 20 (YM20) (10.48%), and CB301 (187.40%) were more responsive to 0.005 ‰ of H2O2, and NC4 (35.37%) obtained the highest shoot regeneration rates at 0.01 ‰ of H2O2. Overall, these two methods, inter-culture and AGP (or H2O2) application, can be further applied to wheat transgenic research.

Changes in the soil nematode community induced by global warming may have a considerable influence on agro-ecosystem functioning. However, the impacts of predicted warming on nematode community in farmland (e.g., winter wheat field) have not been well documented. Therefore, a field experiment with free air temperature increase (FATI) was conducted to investigate the responses of the soil nematode community to nighttime warming in a winter wheat field of Yangtze Delta Plain, China, during 2007 to 2009. Nighttime warming (NW) by 1.8°C at 5-cm soil depth had no significant impact on the total nematode abundance compared to un-warmed control (CK). However, NW significantly affected the nematode community structure. Warming favored the bacterivores and fungivores, such as Acrobeles, Monhystera, Rhabditis, and Rhabdontolaimus in bacterivores, and Filenchus in fungivores, while the plant-parasites were hindered, such as Helicotylenchus and Psilenchus. Interestingly, the carnivores/ omnivores remained almost unchanged. Hence, the abundances of bacterivores and fungivores were significantly higher under NW than those under CK. Similarly, the abundances of plant-parasites were significantly lower under NW than under CK. Furthermore, Wasilewska index of the nematode community was significantly higher under NW than those under CK, indicating beneficial effect to the plant in the soil. Our results suggest that nighttime warming may improve soil fertility and decrease soil- borne diseases in winter wheat field through affecting the soil nematode community. It is also indicated that nighttime warming may promote the sustainability of the nematode community by altering genera-specific habitat suitability for soil biota.