棉花黄萎病使棉花生产受到重大损失。为了揭示棉花响应黄萎病的防御机制，本研究利用棉花品系M138（抗黄萎病）和P2（感黄萎病）进行了转录组分析。结果显示，在M138和P2中分别有11076个和6640个差异表达基因响应黄萎病菌的侵染。利用加权基因共表达网络分析方法对4633个差异表达转录因子进行共表达分析发现，一个与黄萎病菌的抗性反应密切相关的“MEblue”模块，该模块包含654个转录因子。并在这些差异表达转录因子中，发现了参与黄萎病防御反应的关键基因乙烯转录因子GhERF91。进一步，通过病毒诱导的基因沉默实验和外源乙烯利处理分析发现，GhERF91受乙烯诱导表达，并正调控棉花对黄萎病菌的响应。本研究提供了棉花响应黄萎病侵染的转录组数据，同时鉴定了与黄萎病抗性相关的关键基因GhERF91，为选育抗黄萎病的棉花品种提供了的遗传资源。

冷胁迫是影响苹果生产的重要限制因素。在本研究中，我们以苹果砧木‘M9T337’和‘60-160’的组织培养幼苗为试材进行检测，发现它们对冷胁迫分别表现为抗性和敏感性。‘M9T337’和‘60-160’幼苗在冷胁迫（1℃）处理48小时后，差异表达基因（DEGs）的富集途径和生理变化明显不同，表明它们对冷胁迫的反应存在差异。两个砧木幼苗WRKY转录因子差异表达分析表明MdWRKY40is和MdWRKY48为潜在冷耐性调控子。在苹果愈伤中分别过表达MdWRKY40is和MdWRKY48，结果发现过表达MdWRKY48的愈伤没有明显效果，而MdWRKY40is能促进花青苷积累和提高愈伤冷耐性，并促进花青苷合成结构基因MdDFR和冷信号核心基因MdCBF2的表达。酵母单杂和凝胶阻滞（ EMSA ）分析表明MdWRKY40is仅能结合MdDFR的启动子。酵母双杂和双分子荧光互补（BiFC）表明MdWRKY40is能通过其蛋白N端Leu Zipper与CBF2抑制子MdMYB15L互作。当敲除MdWRMY40is蛋白N端Leu Zipper后，在愈伤中过表达发现其不能影响MdCBF2的表达水平和愈伤冷耐性，表明MdWRKY40is参与冷信号途径是通过与MdMYB15L互作来实现的。综上，MdWRKY40is能直接绑定MdDFR启动子促进花青苷积累，并通过与MdMYB15L互作，干扰其对MdCBF2抑制作用，间接促进MdCBF2表达，从而提高冷耐性。这些结果为苹果砧木抗冷机制的研究提供了新视角，为未来筛选抗寒砧木提供分子依据。

本研究通过比较基因表达量和有机酸含量，发现了一个P_3A亚家族成员PbPH5基因的表达量与不同梨系统的苹果酸积累呈高度相关，且与白梨系统、西洋梨系统、砂梨系统和秋子梨系统中的相关性分别是0.932**，0.656*，0.900**和0.518*（*P<0.05或** P<0.01）。在梨果实中过表达PbPH5基因后苹果酸含量增加，沉默PbPH5基因后苹果酸含量降低；亚细胞定位结果显示PbPH5定位于液泡膜。此外，系统发育分析结果表明PbPH5基因是PH5的同源基因，与矮牵牛、苹果和柑橘PH5基因归于同一支。综上所述，这些结果表明PbPH5是一个较为保守的基因，而且，梨果实中苹果酸的积累至少部分与PbPH5基因表达量相关。

细胞死亡是多细胞生物生命中一种重要的生理现象。当呼吸和新陈代谢等正常功能停止时，将会发生细胞死亡。细胞死亡可分为程序性细胞死亡和非程序性细胞死亡。正常组织中发生的程序性细胞死亡，通常是维持组织机能和形态所必须的。非程序性细胞死亡则通常由非生物或生物胁迫引起。近年来，大量研究报道植物在抵御病原菌时出现了细胞死亡现象。通过分析调控植物免疫反应和细胞死亡的蛋白（PICD），发现PICD主要参与丝裂原活化蛋白激酶（MAPK）级联、活性氧（ROS）、植物激素、泛素-蛋白酶体系统、Ca²⁺信号、物质转运等六种主要的反应过程，且这些反应过程存在内在的联系。同时，PICD主要分为八类，如：含有核苷酸结合结构域和富含亮氨酸重复序列的蛋白（NLR）蛋白、受体或类受体激酶、E3泛素连接酶和其相关蛋白、ATP和GTP相关蛋白、转录因子、14-3-3蛋白和其相关蛋白、类eEF1A蛋白和丝氨酸蛋白酶抑制子，部分PICD类型具有单、双子叶植物特异性。植物细胞死亡不仅与病原相关分子模式激发的免疫反应（PTI）、效应因子激发的免疫反应（ETI）紧密相关，也与系统获得性抗性（SAR）存在重要关联。PICD在细胞外基质、细胞膜、细胞质、细胞核、线粒体、叶绿体、内质网膜、多囊泡体等众多细胞结构中均有分布，表明细胞在应对病原菌侵染和调控自身死亡时存在精妙地协同调控作用。此外，植物在抵御病原菌时的细胞死亡，通常对其自身的生长发育不利。通过筛选优异的等位变异和基因编辑等技术手段，期望达到植物免疫和生长发育间的平衡，以此增强PICD在植物应用领域中的潜力。

Soil salinity and alkalinity can inhibit crop growth and reduce yield, and this has become a global environmental concern. Combined changes in nitrogen (N) application and hill density can improve rice yields in sodic saline–alkaline paddy fields and protect the environment. We investigated the interactive effects of N application rate and hill density on rice yield and N accumulation, translocation and utilization in two field experiments during 2018 and 2019 in sodic saline–alkaline paddy fields. Five N application rates (0 (control), 90, 120, 150, and 180 kg N ha⁻¹ (N0–N4), respectively) and three hill densities (achieved by altering the distance between hills, in rows spaced 30 cm apart: 16.5 cm (D1), 13.3 cm (D2) and 10 cm (D3)) were utilized in a split-plot design with three replicates. Nitrogen application rate and hill density significantly affected grain yield. The mathematical model of quadratic saturated D-optimal design showed that with an N application rate in the range of 0–180 kg N ha⁻¹, the highest yield was obtained at 142.61 kg N ha⁻¹ which matched with a planting density of 33.3×10⁴ ha⁻¹. Higher grain yield was mainly attributed to the increase in panicles m^–2. Nitrogen application rate and hill density significantly affected N accumulation in the aboveground parts of rice plants and showed a highly significant positive correlation with grain yield at maturity. From full heading to maturity, the average N loss rate of the aboveground parts of rice plants in N4 was 70.21% higher than that of N3. This is one of the reasons why the yield of N4 treatment is lower than that of the N3 treatment. Nitrogen accumulation rates in the aboveground parts under treatment N3 (150 kg N ha⁻¹) were 81.68 and 106.07% higher in 2018 and 2019, respectively, than those in the control. The N translocation and N translocation contribution rates increased with the increase in the N application rate and hill density, whereas N productivity of dry matter and grain first increased and then decreased with the increase in N application rate and hill density. Agronomic N-use efficiency decreased with an increase in N application rate, whereas hill density did not significantly affect it. Nitrogen productivity of dry matter and grain, and agronomic N-use efficiency, were negatively correlated with grain yield. Thus, rice yield in sodic saline–alkaline paddy fields can be improved by combined changes in the N application rate and hill density to promote aboveground N accumulation. Our study provides novel evidence regarding optimal N application rates and hill densities for sodic saline–alkaline rice paddies.

萝卜是一种重要的十字花科根菜类蔬菜作物，在其有色的根中有高水平的花青素累积。MYB转录因子(TFs)在植物发育和花青素代谢中起着重要作用，并且PAP1/2能促进花青素生物合成基因的表达。本研究在萝卜基因组中共鉴定出187个RsMYB基因，并将其分为32个亚家族；其中159个RsMYB基因被定位在9条染色体上。在4个不同颜色的萝卜品种肉质根发育阶段，14个RsMYB基因表现出差异的表达模式。一些RsMYB基因在成熟期有色根组织中高表达，这些基因包括RsMYB41，RsMYB117以及与PAP1/2同源的RsMYB132在‘NAU-YH’的红色根皮中高表达，RsMYB65和RsMYB159基因在‘NAU-YZH’的紫色根皮中高表达，表明这些RsMYB基因可能促进萝卜肉质根花青素积累。研究结果为进一步研究萝卜RsMYB基因功能特性提供有价值的信息，并有助于阐明萝卜花青素生物合成的分子机制。

It is well known that application of 5-aminolevulinic acid (ALA) could promote the plant growth under abiotic stress in oilseed rape (Brassica napus L.).  However, the specifics of its physiological and ultrastructural regulation under herbicide stress conditions are poorly understood.  In the present study, alleviating role of ALA in B. napus was investigated under four levels of herbicide propyl 4-(2-(4,6-dimethoxypyrimidin-2-yloxy) benzylamino) benzoate (ZJ0273) (0, 100, 200 and
500 mg L^–1) with or without 1 mg L^–1 ALA treated for 48 or 72 h.  Results showed that after 48 h of herbicide stress, the growth of rape seedlings was significantly inhibited with the successive increases of the ZJ0273 concentrations from 0 to 500 mg L^–1, but this inhibition was obviously alleviated by exogenous application of ALA.  However, when treatment time prolonged to 72 h, the recovery effects of ALA could not be evaluated due to the death of plants treated with the highest concentration of ZJ0273 (500 mg L^-1).  Further, the root oxidizability and activities of antioxidant enzymes (superoxide dismutase, peroxidase and ascorbate peroxidase) were dramatically enhanced by the application of 1 mg L^–1 ALA under herbicide stress.  Therefore, plants treated with ALA dynamically modulated their antioxidant defenses to reduce reactive oxygen species (ROS) accumulation and malondialdehyde (MDA) content induced by herbicide stress.  Additionally, exogenously applied ALA improved the ultrastructure’s of chloroplast, mitochondria and nucleus, and induced the production of stress proteins.  Our results suggest that ALA could be considered as a potential plant growth regulator for the improvement of herbicide tolerance through alleviation of the physiological and ultrastructural changes induced by the herbicide in crop production.

There are 41 members of the CCT (CO, CO-like, and TOC1) domain-containing gene family in rice, which are divided into three subfamilies: COL (CONSTANS-like), CMF (CCT motif family), and PRR (pseudoresponse regulator).  The first flowering gene to be isolated by map-based cloning, Heading date 1 (Hd1), which is the orthologue of CO in rice, belongs to COL.  The central regulator of plant development, Ghd7, belongs to CMF.  The major role in controlling rice distribution to high latitudes, Ghd7.1/PRR37, belongs to PRR.  Both of Hd1, Ghd7 and Ghd7.1 simultaneously control grain number, plant height, and the heading date.  To date, 13 CCT family genes from these three subfamilies have been shown to regulate flowering.  Some of them have pleiotropic effects on grain yield, plant height, and abiotic stresses, and others function as circadian oscillators.  There are two independent photoperiod flowering pathways that are mediated by GI-Hd1-Hd3a/RFT and GI-Ehd1-Hd3a/RFT in rice.  CCT family genes are involved in both pathways.  The latest study reveals that protein interaction between Hd1 and Ghd7 integrates the two pathways.  CCT family genes are rich in natural variation because rice cultivars have been subjected to natural and artificial selection for different day lengths in the process of domestication and improvement.  Alleles of several crucial CCT family genes such as Hd1, Ghd7, and Ghd7.1 exhibit geographic distribution patterns and are highly associated with yield potentials.  In addition, CCT family genes are probably involved in the responses to abiotic stress, which should be emphasized in future work.  In general, CCT family genes play important roles in regulating flowering, plant growth, and grain yield.  The functional identification and elucidation of the molecular mechanisms of CCT family genes would help construct a flowering regulatory network and maximize their contribution to rice production.

Traditionally, Chinese indigenous cattle is geographically widespread.  The present study analyzed based on genome-wide variants to evaluate the genetic background among 157 individuals from four representative indigenous cattle breeds of Hubei Province of China: Yiling yellow cattle (YL), Bashan cattle (BS), Wuling cattle (WL), Zaobei cattle (ZB), and 21 individuals of Qinchuan cattle (QC) from the nearby Shanxi Province of China.  Linkage disequilibrium (LD) analysis showed the LD of YL was the lowest (r2=0.32) when the distance between markers was approximately 2 kb.  Principle component analysis (PCA), and neighbor-joining (NJ)-tree revealed a separation of Yiling yellow cattle from other geographic nearby local cattle breeds.  In PCA plot, the YL and QC groups were segregated as expected; moreover, YL individuals clustered  together more obviously.  In the NJ-tree, the YL group formed an independent branch and BS, WL, ZB groups were mixed.  We then used the FST statistic approach to reveal long-term selection sweep of YL and other 4 cattle breeds.  According to the selective sweep, we identified the unique pathways of YL, associated with production traits.  Based on the results, it can be proposed that YL has its unique genetic characteristics of excellence resource, and it is an indispensable cattle breed in China.   

Genomic selection has been demonstrated as a powerful technology to revolutionize animal breeding.  However, marker density and minor allele frequency can affect the predictive ability of genomic estimated breeding values (GEBVs).  To investigate the impact of marker density and minor allele frequency on predictive ability, we estimated GEBVs by constructing the different subsets of single nucleotide polymorphisms (SNPs) based on varying markers densities and minor allele frequency (MAF) for average daily gain (ADG), live weight (LW) and carcass weight (CW) in 1 059 Chinese Simmental beef cattle.  Two strategies were proposed for SNP selection to construct different marker densities: 1) select evenly-spaced SNPs (Strategy 1), and 2) select SNPs with large effects estimated from BayesB (Strategy 2).  Furthermore, predictive ability was assessed in terms of the correlation between predicted genomic values and corrected phenotypes from 10-fold cross-validation.  Predictive ability for ADG, LW and CW using autosomal SNPs were 0.13±0.002, 0.21±0.003 and 0.25±0.003, respectively.  In our study, the predictive ability increased dramatically as more SNPs were included in analysis until 200K for Strategy 1.  Under Strategy 2, we found the predictive ability slightly increased when marker densities increased from 5K to 20K, which indicated the predictive ability of 20K (3% of 770K) SNPs with large effects was equal to the predictive ability of using all SNPs.  For different MAF bins, we obtained the highest predictive ability for three traits with MAF bin 0.01–0.1.  Our result suggested that designing a low-density chip by selecting low frequency markers with large SNP effects sizes should be helpful for commercial application in Chinese Simmental cattle.

Both bolting and flowering times influence taproot and seed production in radish. FLOWERING LOCUS C (FLC) plays a key role in plant flowering by functioning as a repressor. Two genomic DNA sequences, a 3 046-bp from an early- and a 2 959-bp from a late-bolting radish line were isolated and named as RsFLC1 and RsFLC2, respectively, for they share approximately 87.03% sequence identity to the FLC cDNA sequences. The genomic DNA sequences, 1 466-bp and 1 744-bp, flanking the 5´-regions of RsFLC1 and RsFLC2, respectively, were characterized. Since both of them harbor the basic promoter elements, the TATA box and CAAT box, they were designated as PRsFLC1 and PRsFLC2. The transcription start site (TSS) was identified at 424 and 336 bp upstream of the start codon in PRsFLC1 and PRsFLC2, respectively. cis-regulatory elements including CGTCA (MeJA-responsive) and ABRE (abscisic acid-responsive) motifs were found in both promoters, while some cis-regulatory elements including TCA element and GARE-motif were present only in PRsFLC1. These sequence differences lead to the diversity of promoter core elements, which could partially result in the difference of bolting and flowering time in radish line NauDY13 (early-bolting) and Naulu127 (late-bolting). Furthermore, to investigate the activity of these promoters, a series of 5´-deletion fragment-GUS fusions were constructed and transformed into tobacco. GUS activity was detected in PRsFLC1-(1 to 4)-GUS-PS1aG-3 and PRsFLC2-(1 to 4)-GUS-PS1aG-3 transgenic tobacco leaf discs, and this activity progressively decreased from PRsFLC-1-GUS-PS1aG-3 to PRsFLC-5-GUS-PS1aG-3. Deletion analysis indicated that the cis-regulatory elements located at –395 bp to +1 bp may be critical for specifying RsFLC gene transcription.

Organophosphate insecticide residues on vegetable, fruit, tea and even grains are primary cause of food poisoning. Organophosphate compounds can cause irreversible inhibition of the activity of acetylcholinesterase and butyrylcholinesterase (BChE, EC 3.1.1.8), which are both candidates for rapid detection of organophosphate pesticides. To develop an easy-tohandle method for detecting organophosphate pesticides using BChE, BChE from human was optimized according to the codon usage bias of Pichia pastoris and successfully expressed in P. pastoris GS115. The codon-optimized cDNA shared 37.3% of the codon identity with the native one. However, the amino acid sequence was identical to that of the native human butyrylcholinesterase gene (hBChE) as published. The ratio of guanine and cytosine in four kinds of bases ((G+C) ratio) was simultaneously increased from 40 to 47%. The recombinant hBChE expression reached a total protein concentration of 292 mg mL–1 with an activity of 14.7 U mL–1, which was purified 3.2×103-fold via nickel affinity chromatography with a yield of 68% and a specific activity of 8.1 U mg–1. Recombinant hBChE was optimally active at pH 7.4 and 50°C and exhibited high activity at a wide pH range (>60% activity at pH 4.0 to 8.0). Moreover, it had a good adaptability to high temperature (>60% activity at both 50 and 60°C up to 60 min) and good stability at 70°C. The enzyme can be activated by Li+, Co+, Zn2+ and ethylene diamine tetraacetic acid (EDTA), but inhibited by Mg2+, Mn2+, Fe2+, Ag+ and Ca2+. Na+ had little effect on its activity. The values of hBChE of the Michaelis constant (Km) and maximum reaction velocity (Vm) were 89.4 mmol L–1 and 1 721 mmol min–1 mg–1, respectively. The bimolecular rate constants (Ki) of the hBChE to four pesticides were similar with that of electric eel AChE (EeAChE) and higher than that of horse BChE (HoBChE). All values of the half maximal inhibitory concentration of a substance (IC50) for hBChE were lower than those for HoBChE, but most IC50 for hBChE were lower than those for EeAChE except dichlorvos. The applicability of the hBChE was further verified by successful detection of organophosphate insecticide residues in six kinds of vegetable samples. Thus, hBChE heterologously over-expressed by P. pastoris would provide a sufficient material for development of a rapid detection method of organophosphate on spot and produce the organophosphate detection kit.

    Quorum sensing (QS) is a type of microbe-microbe communication system that is widespread among the microbial world, particularly among microorganisms that are symbiotic with plants and animals. Thereby, the cell-cell signalling is likely to occur in an anaerobic rumen environment, which is a complex microbial ecosystem. In this study, using six ruminally fistulated Liuyang black goats as experimental animals, we aimed to detect the activity of quorum sensing autoinducers (AI) both in vivo and in vitro and to clone the luxS gene that encoded autoinducer-2 (AI-2) synthase of microbial samples that were collected from the rumen of goats. Neutral detergent fiber (NDF) and soluble starch were the two types of substrates that were used for in vitro fermentation. The fermented fluid samples were collected at 0, 2, 4, 6, 8, 12, 24, 36, and 48 h of incubation. The acyl-homoserine lactones (AHLs) activity was determined using gas chromatography-mass spectrometer (GC-MS) analysis. However, none of the rumen fluid extracts that were collected from the goat rumen showed the same or similar fragmentation pattern to AHLs standards. Meanwhile, the AI-2 activity, assayed using a Vibrio harveyi BB170 bioassay, was negative in all samples that were collected from the goat rumen and from in vitro fermentation fluids. Our results indicated that the activities of AHLs and AI-2 were not detected in the ruminal contents from six goats and in ruminal fluids obtained from in vitro fermentation at different sampling time-points. However, the homologues of luxS in Prevotella ruminicola were cloned from in vivo and in vitro ruminal fluids. We concluded that AHLs and AI-2 could not be detected in in vivo and in vitro ruminal fluids of goats using the current detection techniques under current dietary conditions. However, the microbes that inhabited the goat rumen had the potential ability to secrete AI-2 signaling molecules and to communicate with each other via AI-2-mediated QS because of the presence of luxS.

The objective of the present investigation was to estimate the prevalence of Toxoplasma gondii infection and co-infection with porcine reproductive and respiratory syndrome virus (PRRSV), classical swine fever virus (CSFV) and porcine circovirus type 2 (PCV-2) in pigs in China. A total of 372 tissues or serum samples collected from pigs distributed in 9 provinces/ municipalities of China during the period from February 2011 to November 2012 were assayed for T. gondii antigens and antibodies using enzyme linked immunosorbent assay (ELISA) technique, while the PCR was designed for the detection of the PRRSV, CSFV and PCV-2, respectively. The total positive rate of T. gondii, PRSSV, CSFV and PCV-2 was 9.14% (34/372), 50.00% (186/372), 37.10% (138/372) and 3.23% (12/372), respectively. Among the 34 T. gondii positive samples, 26 samples were simultaneously infected with T. gondii and viruses, while the remaining eight samples were infected with T. gondii alone. In addition, the co-infection rate of T. gondii with PRSSV, T. gondii with PRSSV and CSFV, T. gondii with PRSSV and PCV-2, T. gondii with CSFV and PCV-2, T. gondii with PRSSV, CSFV and PCV-2 was 1.61% (6/372), 4.03% (15/372), 0.27% (1/372), 0.27% (1/372) and 0.81% (3/372), respectively. The results of the present survey revealed that PRRSV and CSFV were the common pathogens co-existing with porcine toxoplasmosis in China, and both of them could increase the chances of T. gondii infection in pig. This is the first report of T. gondii co-infections with viruses in pigs. It is very important to understand the interactions of parasite and virus, and can be used as reference data for the control and prevention of co-infections of T. gondii and viruses in pigs.

In this study, four strains of Toxoplasma gondii with the same genetic type (Type I) originated from chicken, human, cat and swine were used to compare the immune responses in resistant chicken host to investigate the relationships between the parasite origins and the pathogenicity in certain host. A total of 300, 10-day-old chickens were allocated randomly into five groups which named JS (from chicken), CAT (from cat), CN (from swine), RH (from human) and a negative control group (–Ve) with 60 birds in each group. Tachyzoites of four different T. gondii strains (JS, CAT, CN and RH) were inoculated intraperitoneally with the dose of 1×107 in the four designed groups, respectively. The negative control (–Ve) group was mockly inoculated with phosphate-buffered saline (PBS) alone. Blood and spleen samples were obtained on the day of inoculation (day 0) and at days 4, 11, 25, 39 and 53 post-infection to screen the immunopathological changes. The results demonstrated some different immune characters of T. gondii infected chickens with that of mice or swine previous reported. These differences included up-regulation of major histocompatibility complex class II (MHC II) molecules in the early stage of infection, early peak expressions of interleukin (IL)-12 (IL-12) and -10 (IL-10) and long keep of IL-17. These might partially contribute to the resistance of chicken to T. gondii infection. Comparisons to chickens infected with strains from human, cat and swine, chickens infected with strain from chicken showed significant high levels of CD4+ and CD8+ T cells, interferon gamma (IFN-γ), IL-12 and IL-10. It suggested that the strain from chicken had different ability to stimulate cellular immunity in chicken.

The bacterial brown spot disease (BBS), caused primarily by Pseudomonas syringae pv. syringae van Hall (Pss), reduces plant vigor, yield and quality in maize. To reveal the nature of the defense mechanisms and identify genes involved in the effective host resistance, the dynamic changes of defense transcriptome triggered by the infection of Pss were investigated and compared between two maize near-isogenic lines (NILs). We found that Pss infection resulted in a sophisticated transcriptional reprogramming of several biological processes and the resistant NIL employed much faster defense responses than the susceptible NIL. Numerous genes encoding essential components of plant basal resistance would be able to be activated in the susceptible NIL, such as PEN1, PEN2, PEN3, and EDR1, however, in a basic manner, such resistance might not be sufficient for suppressing Pss pathogenesis. In addition, the expressions of a large number of PTI-, ETI-, PR-, and WRKY-related genes were pronouncedly activated in the resistant NIL, suggesting that maize employ a multitude of defense pathways to defend Pss infection. Six R-gene homologs were identified to have significantly higher expression levels in the resistant NIL at early time point, indicating that a robust surveillance system (gene-to-gene model) might operate in maize during Pss attacks, and these homolog genes are likely to be potential candidate resistance genes involved in BBS disease resistance. Furthermore, a holistic group of novel pathogen-responsive genes were defined, providing the repertoire of candidate genes for further functional characterization and identification of their regulation patterns during pathogen infection.

Eight compounds were isolated from the fermentation cultures of rice sheath blight pathogen Rhizoctonia solani Kühn. They were identified as ergosterol (1), 6β-hydroxysitostenone (2), sitostenone (3), m-hydroxyphenylacetic acid (4), methyl m-hydroxyphenylacetate (5), m-hydroxymethylphenyl pentanoate (6), (Z)-3-methylpent-2-en-1,5-dioic acid (7) and 3-methoxyfuran-2-carboxylic acid (8) by means of physicochemical and spectroscopic analysis. Among them, 2, 3, 5–8 were isolated from R. solani for the first time. All the compounds were evaluated for their biological activities. 4–6 and 8 showed their inhibitory activities on the radical and germ elongation of rice seeds. 1, 4 and 7 showed moderate antibacterial activity to some bacteria. 4, 7 and 8 exhibited weak inhibitory activities on spore germination of Magnaporthe oryzae. 8 showed moderate antioxidant activity with the 1,1-diphenyl-2-picryhydrazyl (DPPH) and β-carotene-linoleic acid assays. This is the first time to reveal compounds 5, 6 and 8 from rice sheath blight pathogen R. solani to have in vitro phytotoxic activity.

Myrosinase is a defense-related enzyme and is capable of hydrolyzing glucosinolates into a variety of compounds, some of which are toxic to pathogens and herbivores. Many studies revealed that a number of important vegetables or oil crops contain the myrosinase-glucosinolate system. However, the related promoter and genomic DNA sequences as well as expression profiles of myrosinase gene remain largely unexplored in radish (Raphanus sativus). In this study, the 2 798 bp genomic DNA sequence, designated as RsMyr2, was isolated and analyzed in radish. The RsMyr2 consisting of 12 exons and 11 introns reflected the common gene structure of myrosinases. Using the genomic DNA walking approach, the 5´-flanking region upstream of RsMyr2 with length of 1 711 bp was successfully isolated. PLACE and PlantCARE analyses revealed that this upstream region could be the promoter of RsMyr2, which contained several basic cis-regulatory elements including TATA-box, CAAT-box and regulatory motifs responsive to defense and stresses. Furthermore, recombinant pET-RsMyr2 protein separated by SDS-PAGE was identified as myrosinase with mass spectrometry. Real-time PCR analysis showed differential expression profiles of RsMyr2 in leaf, stem and root at different developmental stages (e.g., higher expression in leaf at cotyledon stage and lower in flesh root at mature stage). Additionally, the RsMyr2 gene exhibited up-regulated expression when treated with abscisic acid (ABA), methyl jasmonate (MeJA) and hydrogen peroxide (H2O2), whereas it was down-regulated by wounding (WO) treatment. The findings indicated that the expression of RsMyr2 gene was differentially regulated by these stress treatments. These results could provide new insight into elucidating the molecular characterization and biological function of myrosinase in radish.

Downy mildew (DM), caused by the fungus Peronospora parasitica, is a destructive disease of radish (Raphanus sativus L.) worldwide. Host resistance has been considered as an attractive and environmentally friendly approach to control the disease. However, the genetic mechanisms of resistance in radish to the pathogen remain unknown. To determine the inheritance of resistance to DM, F1, F2 and BC1F1 populations derived from reciprocal crosses between a resistant line NAU-dhp08 and a susceptible line NAU-qtbjq-06 were evaluated for their responses to DM at seedling stage. All F1 hybrid plants showed high resistance to DM and maternal effect was not detected. The segregation for resistant to susceptible individuals statistically fitted a 3:1 ratio in two F2 populations (F2(SR) and F2(RS)), and 1:1 ratio in two BC1F1 populations, indicating that resistance to DM at seedling stage in radish was controlled by a single dominant locus designated as RsDmR. A total of 1 972 primer pairs (1036 SRAP, 628 RAPD, 126 RGA, 110 EST-SSR and 72 ISSR) were screened, and 36 were polymorphic between the resistant and susceptible bulks, and consequently used for genotyping individuals in the F2 population. Three markers (Em9/ga24370, NAUISSR826700 and Me7/em10400) linked to the RsDmR locus within a 10.0 cM distance were identified using bulked segregant analysis (BSA). The SRAP marker Em9/ga24370 was the most tightly linked one with a distance of 2.3 cM to RsDmR. These markers tightly linked to the RsDmR locus would facilitate marker-assisted selection and resistance gene pyramiding in radish breeding programs.

The soil organic matter and nutrients are fundamental for the sustainability of pear production, but little is known about the spatial distribution of soil organic matter and nutrients in a pear orchard. With the soil of the pear (cv. Dangshansu on P.betulifolia Bunge. rootstock) orchard under clean and sod cultivation models as test materials, the experiment was conducted to evaluate spatial variability of soil organic matter (SOM), total nitrogen (STN), total phosphorus (STP), total potassium (STK), available nitrogen (SAN), and available potassium (SAK) in and between rows at different soil depths (0-60 cm). The SOM, STN, STP, STK, SAN and SAK of the different soil layers under the two tillage models were different in the vertical direction. The SOM, STN, STP and SAN in the 0-20 cm soil layer were higher than those in the 20-40 and 40- 60 cm soil layers. The STK of 40-60 cm soil layer was higher than that in the 0-20 and 20-40 cm soil layers. The STK increased with the depth of soil in the vertical direction in the clean cultivated pear orchard. Variability of the SOM, STN, STP, STK, SAN and SAK of sample sites in between rows of the same soil layer was found in the pear orchard soil in the horizontal direction under clean and sod cultivation management systems, except that STK of all sites did not show the difference in identical soil layers in the pear orchard under clean cultivation. The sod cultivation model improved the SOM, STN, and STK in the 0-20 cm soil layer in the pear orchard, and the three components increased by 12.8, 12.7 and 7.3% compared to clean cultivation, respectively. The results can be applicable to plan collection of orchard soil samples, assess orchard soil quality, and improve orchard soil management practices.

One strain of Toxoplasma gondii was successfully isolated from chickens in China by bioassay in mice. Antibodies and circulating antigens of T. gondii were assayed by the ELISA kits in 100 free range chickens from a rural area surrounding Funing, China. Fifty-three chickens were antibody-positive and 21 chickens were antigen positive. Hearts, brains, spleens, lungs, livers, and kidneys of 21 antibody or antigen-positive chickens were bioassayed in mice. One strain of T. gondii was isolated from 1 of 21 (4.76%) chickens. The isolated T. gondii killed all of the inoculated mice. Genotyping of this isolate using polymorphisms at the loci 5´-SAG2, 3´-SAG2, SAG3, cB21-4, L358, BTUB, and GRA6 revealed that it was Type I. These indicated that it was virulent for mice. This is the first report of isolation of T. gondii from chickens in China.

Regrowth traits of alfalfa (Medicago sativa L.) in spring are closely related to its fall dormancy before winter. In order todetermine the relationship between fall dormancy (FD) grade and hormone variation pattern and provide academic referencesfor the variety improvement and production of alfalfa, the variations of gibberellins (GA3), indole-3-acetic acid (IAA), andabscisic acid (ABA) in alfalfa roots during regrowth period in spring were examined by high performance liquidchromatography (HPLC). The study involved seven alfalfa cultivars that belonged to four fall dormant grades, i.e., 2, 4, 6,and 8. The results showed that the differences in spring regrowth among the alfalfa cultivars were partially associatedwith their root hormone levels. The alfalfa cultivars that belonged to the same dormancy grades presented similarvariation trends in endogenous hormone content in their roots during the spring regrowth stage. At the early regrowthstage, cultivars with a higher dormant grade had a higher GA3 concent and a lower ABA content in their roots than thecultivars with a lower dormant grade; and IAA content in roots of non- and semi-fall dormancy cultivars was higher thanthat of fall dormancy cultivars. During the whole period of spring regrowth, the root ABA content of fall dormancy alfalfacultivar is significantly higher than those of semi- and non-fall dormancy cultivars. GA3 contents in the roots of allcultivars under study showed a double-peak dynamic curve; root IAA contents of the studied cultivars presented adownward trend. But the trend did not significantly differed among the different fall dormant cultivars. The higher GA3content and lower ABA content in root of non-fall dormancy alfalfa lead to its earlier regrowth. Regrowth time and rate ofalfalfa can be regulated by exogenous GA3 or ABA at the early regrowth stage to meet producing requirement.