腐烂茎线虫（Ditylenchus destructor）是一种重要的检疫性病原线虫，严重危害甘薯、马铃薯和中药材等根茎类作物。该线虫的种内分化明显，根据ITS-rDNA序列差异，国外的研究将其分为A-G 7个单倍型，但主要集中于马铃薯和甘薯的线虫群体。本研究对腐烂茎线虫中药材群体ITS-rDNA序列及其RNA二级结构进行分析，以明确其单倍型分化，并通过ITS-rDNA与28S D2-D3系统发育关系、ITS-RFLR和ITS特异性引物PCR扩增进一步验证不同群体单倍型的分化。在甘肃、青海、陕西、内蒙和黑龙江等5个省，共采集当归、党参、马铃薯和甘薯的腐烂茎线虫群体43个，其中中药材群体37个。线虫群体的ITS-rDNA序列长度为727 bp-969 bp，长度差异主要表现在ITS1区串联重复序列的数量不同，且串联重复序列在ITS1二级结构中形成了稳定的茎环，即H9螺旋。依据H9螺旋结构的有无及其差异，43个群体的ITS-rDNA序列可划分为10个单倍型。与已知单倍型（A-G）对比分析，发现其中3个单倍型分别与A、B和C单倍型一致，而另外7个单倍型与已知单倍型不同，将其依次命名为H、I、J、K、L、M和N单倍型，这7个新单倍型均来源于中药材。综合本研究和已知单倍型分类体系，腐烂茎线虫中发现A-N 14个单倍型。ITS和28S系统发育分析显示，所有单倍型群体分化为两支：A单倍型为一支，B-N单倍型为另一支。对比ITS和28S系统发育树，发现A单倍型均单独聚为一支，但B-N分支不太一致，且不同单倍型系统发育关系较为混乱。ITS-RFLP和特异性引物PCR结果显示，H和A单倍型酶切图谱和特异性片段长度相同， B和C单倍型特异性片段长度相同，但其它单倍型间存在明显差异。除K单倍型不同群体间有差异外，其它单倍型的群体间无明显差异。本研究发现了腐烂茎线虫中药材群体中存在新的单倍型，并明确了不同单倍型的差异，该结果将推动茎线虫生物学的研究进展，且对中药材腐烂茎线虫病的识别和防治具有指导意义。

本研究的目的旨在确定鸡PPARγ对Plin1基因的调控作用，并阐明其确切的分子机制。本研究首先利用RT-qPCR技术检测PPARγ激动剂对cPlin1基因表达的影响，而后通过双荧光素酶报告基因和RT-qPCR技术分析PPARγ对cPlin1基因启动子活性和mRNA表达的影响，再通过免疫共沉淀和双荧光素酶报告基因技术研究PPARγ与RXRα的协同作用对cPlin1基因启动子活性的影响，最后通过启动子截短和突变分析以及凝胶阻滞技术确定cPlin1基因启动子中PPARγ2的具体调控位点。基因表达分析结果表明，PPARγ的特异性激动剂—曲格列酮可以显著增强（P<0.05）PPARγ的靶基因LPL、A-FABP、FAS基因和Plin1基因的mRNA表达水平，提示cPlin1基因的表达可能受PPARγ的调控；进一步的报告基因和基因表达分析结果表明，PPARγ2能够显著促进（P<0.01）cPlin1基因的启动子活性及mRNA表达水平，但PPARγ1却无此作用；免疫共沉淀和报告基因结果表明，PPARγ与RXRα之间存在蛋白质相互作用；与单独过表达RXRα相比，共表达PPARγ2和RXRα显著增强（P<0.01）cPlin1基因的启动子活性，但共表达PPARγ1和RXRα则没有表现出类似的现象；启动子的截短及突变分析以及凝胶阻滞结果表明，PPARγ2可以与cPlin1基因启动子上的-1126/-1116位点结合促进（P<0.01）cPlin1基因的表达。与哺乳动物相似，（i）鸡PPARγ对Plin1基因的转录具有正调控作用，其中PPARγ2是发挥此调控作用的主要蛋白亚型；（ii）PPARγ2是通过与cPlin1基因启动子区域的-1126/-1116位点结合来实现促进cPlin1基因表达作用的。本研究的创新性是明确了鸡PPARγ对Plin1基因表达的调控作用，并揭示了PPARγ2调控鸡Plin1基因转录的分子机制。

我们利用宏基因组技术研究了玉米种植模式、土壤性质和地理位置对中国4个玉米主产区土壤原核生物群落的影响。在本研究所有土壤样品中，α-变形菌纲、γ-变形菌纲、β-变形菌纲、芽单胞菌纲、酸杆菌纲和放线菌纲是共同优势原核生物类群。非度量多维尺度法分析发现，原核生物群落划分4个组，且与4个玉米种植区相吻合。冗余分析表明，土壤性质(尤其是pH)、地理位置和种植模式共同影响土壤原核生物群落多样性，而地理位置（纬度）、pH和种植模式影响土壤原核生物功能基因。4个玉米生产区土壤原核生物某些代谢途径中的功能基因丰度差异显著，如微生物-微生物相互作用、芳香化合物降解、原核生物固碳途径和微生物在不同环境中代谢等。总之，土壤pH、种植制度和地理位置三者共同影响了我国4个玉米主产区土壤原核生物群落和功能基因。研究结果有助于深入了解大尺度农业生态系统中土壤原核生物群落的组成和基因功能。

本研究以东北农业大学鸡F₂资源群体（NEAURP）为材料，利用 Illumina HiSeq PE150平台进行全基因组测序（26个F₀个体进行10×重测序，519个F₂个体进行3×重测序）。使用SAMtools进行SNP calling，BEAGLE 4.0在默认参数设置下进行基因型填充。经过质量控制和基因型填充后，共有7,890,258个SNPs用于分析。根据GRCg6a参考基因组，使用ANNOVAR软件进行SNP注释。基于混合线性模型（MLM），使用GEMMA软件进行全基因组关联分析。使用F_ST和π两种选择信号方法评估F₂群体的遗传分化和遗传多样性。 GWAS与选择信号的整合分析表明，控制鸡骨骼肌产肉性状的遗传因子主要位于第1染色体（168.95Mb-172.43Mb）和第4染色体（74.37Mb-75.23Mb）上，共鉴定出17个可能影响目标性状的位置候选基因（ LRCH1、CDADC1、CAB39L、LOC112531568、LOC112531569、FAM124A、FOXO1、NBEA、GPALPP1、RUBCNL、ARL11、KPNA3、LHFP、GBA3、LOC112532426、KCNIP4、SLIT2），其中KPNA3和FOXO1是与鸡产肉性状相关的强烈候选基因。本研究的主要创新点是结合GWAS和选择信号分析方法解析鸡骨骼肌产肉性状的遗传结构，发现了一些新的影响鸡产肉性状的基因组区域和候选基因。

本研究以东北农业大学肉鸡高、低腹脂双向选择品系1-7周龄鸡只和永生化鸡前脂肪细胞（ICP2细胞）为材料，利用RT-qPCR和Western blot方法分析HBP1在脂肪组织和前脂肪细胞分化过程中的表达模式；以稳定过表达HBP1的ICP2细胞、敲除HBP1的ICP2细胞以及各自的对照细胞为材料，利用油红O染色、RT-qPCR和Western blot检测过表达/敲除HBP1对鸡前脂肪细胞分化的影响；利用信号通路分析试剂盒筛选HBP1调控鸡前脂肪细胞分化的潜在信号通路；在稳定过表达HBP1的ICP2细胞中添加信号转导和转录激活因子3（STAT3）的化学抑制剂或转染siRNA进行功能拯救实验。结果：基因表达分析结果表明，HBP1的表达与鸡腹部脂肪沉积和前脂肪细胞分化有关。过表达HBP1抑制鸡前脂肪细胞分化（P<0.05），敲除HBP1促进鸡前脂肪细胞分化（P<0.05）。进一步研究发现，HBP1靶向激活Janus激酶2（JAK2）基因的转录来激活STAT3信号通路。功能拯救实验结果表明，STAT3信号介导了HBP1对鸡前脂肪细胞分化的调控作用。以上结果表明，HBP1通过直接上调JAK2的表达来激活STAT3信号通路，从而抑制鸡前脂肪细胞的分化。本研究阐明了HBP1在鸡前脂肪细胞分化中的基本功能，并揭示了其部分分子机制。这些发现为进一步解析鸡脂肪组织生长发育的分子遗传基础提供了新的见解。

禾谷孢囊线虫H. avenae是一种重要的植物病原线虫，严重影响禾谷类作物的产量。目前已在我国河南、河北、江苏、青海、西藏等16个省(市)发生危害。本研究通过人工接种试验和田间试验，利用抽穗期根系中的线虫数量指标评价了青海栽培二棱大麦 (QH2R)、青海栽培六棱大麦 (QH6R) 和西藏栽培二棱大麦 (TB2R) 对禾谷孢囊线虫的抗病性，并通过接种试验和显微观察，评价了两个高抗品种中线虫的侵染和发育情况。为更好地评价不同品种对H. avenae的抗感性，首先比较了两种常用的抗性评价方法——繁育系数法 (PPR) 和单株雌虫/孢囊数量法 (NFP) 的准确性。对田间自然条件下186个品种受害情况的调查结果表明，利用NFP法鉴定出的感病品种数量显著高于PPR法鉴定的感病品种数量，表明NFP法更利于鉴定大麦品种的抗病性。通过2015年至2017年的田间试验及2018年的人工接种试验，发现QH2R系列品种中形成的雌虫/孢囊数量最少，显著低于QH6R和TB2R系列品种。综合接种试验与田间试验的结果，从QH2R系列品种中鉴定出8个高抗品种 (Sunong7617, Sunong7635, Dongyuan87-14, Rudong14-46, Rudong87-57, Rudong87-8-45, Rudong88-14-2, Rudong88-67-1)，平均单株孢囊数量低于4.2个。对线虫发育进程的显微观察表明，高抗品种 (Sunong7635和Dongyuan87-14) 中H. avenae幼虫的侵入数量显著低于感病品种中幼虫的侵入数量，并且幼虫发育成雌虫的数量也显著减少。本研究中鉴定的高抗品种对于育种工作者培育禾谷孢囊线虫抗性品种、更加经济有效地控制禾谷孢囊线虫的危害等具有重要意义。

自2018年8月非洲猪瘟在中国爆发以来，在信息快速传播的时代受到全社会的广泛关注。非洲猪瘟的发生发展导致猪肉等主要肉类市场供需失衡，肉类价格大幅剧烈波动。为了分析非洲猪瘟对猪肉等肉类价格的影响，本文采用网络爬虫方法构建了基于互联网非洲猪瘟关注度指数作为非洲猪瘟疫情的代理变量，运用时变参数向量自回归模型 (TVP-VAR) 分析了非洲猪瘟与肉类价格的动态关系。研究发现，非洲猪瘟对猪肉、鸡肉、牛羊肉价格的影响程度、方向和时滞上存在差异，且影响效应有显著的时变特征；同时，非洲猪瘟对肉类价格的影响程度与非洲猪瘟的发展趋势和程度并不一致，脉冲强度与非洲猪瘟的强度和持续时间强相关且脉冲强度在早期普遍较弱，中后期显著增强。未来应加强对非猪瘟的宏观调控，强化市场监测预警，规范生产流通和舆论监测引导，以期而稳定肉类市场预期，促进畜禽市场平稳运行。

斑点叶（spl）突变体属于一种植物类病斑突变体。我们通过甲基磺酸乙酯（EMS）诱变小麦栽培品种国麦301，获得了一些类病斑突变体，其中一种因其叶片上有白色条纹而被命名为白色条纹叶（wsl）突变体。本文报告这个新的小麦突变体wsl的遗传和基因定位。在整个生育期，突变体wsl的叶片上均有白色条纹出现。随着植株的生长，白色条纹加重，坏死斑面积增大。突变体wsl在拔节前长势较弱，拔节过后长势逐渐恢复。突变体wsl旗叶的长和宽、单株有效穗数和千粒重均显著低于其野生型亲本国麦301。遗传分析表明，wsl的白色条纹性状受１对隐性核基因控制，命名为wsl。利用两个F2群体（wsl×中国春和wsl×济麦22），通过SSR分子标记连锁分析，将wsl基因定位在小麦6BS染色体臂上。在wsl×中国春杂交分离群体中，筛选到4个与wsl基因连锁的标记，Xgpw1079-Xwmc104-Xgwm508-wsl-Xgpw7651，遗传距离分别为7.1, 5.2, 8.7和4.4 cM。在wsl×济麦22杂交分离群体中，筛选到3个与wsl基因连锁的标记，Xgwm508-Xwmc494-Xgwm518-wsl，遗传距离分别为3.5, 1.6和8.2 cM。参考中国春基因组序列，wsl位于6BS染色体88 Mb （Xgwm518）~ 179 Mb （Xgpw7651）之间的91 Mb物理区间内。突变体wsl是研究小麦叶片发育分子机制的重要新种质。

草地贪夜蛾于2018年入侵亚洲后，迅速扩散，成为影响玉米生产安全的重大害虫。农药的使用减缓了草地贪夜蛾的为害，但由于长期使用的局限性，可替代或辅助农药的生物防治技术目前依然是国内外关注的焦点。大灰食蚜蝇（双翅目：食蚜蝇科）是玉米等多种作物田内的优势天敌昆虫，可取食草地贪夜蛾幼虫。本研究在室内模拟田间环境，研究了大灰食蚜蝇Eupeodes corollae幼虫对草地贪夜蛾卵和不同龄期幼虫的捕食能力。结果表明，2龄、3龄大灰食蚜蝇幼虫对1龄和2龄草地贪夜蛾的幼虫具有捕食作用，理论日最大捕食量分别为43.48头和83.33头。当草地贪夜蛾幼虫发育至3龄后，显现出对低龄大灰食蚜蝇幼虫的捕食行为，5龄和6龄草地贪夜蛾幼虫对1龄、2龄、3龄大灰食蚜蝇的理论日最大捕食量分别为16.39-19.23头、6.02-19.61头和6.76-8.26头，捕食作用符合功能反应Ⅲ。表明草地贪夜蛾幼虫与大灰食蚜蝇存在捕食互作关系，其入侵后将影响大灰食蚜蝇等天敌昆虫的种群动态。综上，本试验为鳞翅目害虫与天敌昆虫的互作关系研究提供了新的思路，对综合评价草地贪夜蛾与天敌昆虫的物种关系和发展生物防治技术具有重要意义。

根际微生物群及其中的解磷细菌在维持集约化农业系统的可持续性和生产力方面具有重要潜力。施肥制度能够影响土壤微生物群落，然而目前仍不清楚土壤中哪些群落的变化会影响有益菌群在根际的富集。本研究基于曲周实验站的一个长期定位实验，该实验始于1993年，含有堆肥、生物堆肥、化肥或不施肥的四个不同处理。利用选择性培养法、16S rRNA基因的Illumina测序，比较了不同处理下玉米根际总细菌和解磷细菌的多样性和群落结构的动态。研究结果显示：玉米的发育期是影响根际细菌和解磷细菌种群结构的主要因子，分别能够解释29%和13%的变异，作用高于不同的施肥。施用堆肥或生物堆肥的土壤中副球菌属的相对丰度显著高于施用化肥或不施肥处理。在根际富集的属中，海洋芽胞杆菌属、芽孢杆菌属、无色杆菌属、剑菌属、 副球菌属、Ramlibacter和藤黄单胞菌属的相对丰度与其在土壤中的相对丰度呈正相关。解磷细菌中剑菌属、芽孢杆菌属和链霉菌属的相对丰度也表现出上述规律。综上所述，尽管玉米发育期是影响根际微生物群的主要因素，但施肥制度或也能够影响根际有益微生物群，如芽孢杆菌属和剑菌属。

瘦素受体（LEPR）是瘦素的高亲和力受体，在人类和动物肥胖中起着至关重要的作用。本研究的目的是以东北农业大学肉鸡双向选择品系（NEAUHLF）为研究材料，通过关联分析和电子计算分析相结合的方法，研究LEPR外显子功能变异对鸡脂肪沉积的影响。使用5种在线生物信息学工具预测编码区单核苷酸多态性（SNPs）的功能。进一步，通过基于氨基酸残基的保守性和稳定性分析、蛋白质配体结合位点的预测、蛋白质二级结构分析、蛋白质三级结构的建模等生物信息学分析，确定了高置信度SNPs的可能结构与功能。同时，对鸡LEPR基因外显子20个非同义单核苷酸多态性（nsSNPs）与腹脂性状进行了关联分析。5种在线生物信息学工具显示，rs731962924(N867I)和rs13684622（C1002R）是最可能影响鸡腹部脂肪性状的功能性nsSNPs。氨基酸残基稳定性和保守型分析显示，大部分nsSNPs可引起蛋白质稳定性下降，rs731962924（N867I）和rs13684622（C1002R）在进化过程中相对保守。蛋白质结构分析显示rs731962924（N867I）和rs13684622（C1002R）均在可引起LEPR蛋白质结构和功能的显著变化。关联分析显示rs13684622（C1002R）与鸡腹脂重和腹脂率显著相关（P=0.0413，P=0.0260）。因此，我们认为rs13684622（C1002R）可能是一个影响鸡腹脂沉积的重要功能性SNP，有望应用于分子标记辅助选择（MAS）中培育低脂肉鸡品系。本研究的主要创新点是结合了多种生物信息学方法和nsSNPs与腹脂性状之间的关联分析进行LEPR基因功能性SNPs的筛选，为后续进行深入的功能分析提供优先研究SNP（priorization SNP）。此外，本研究用到的关联分析与计算机电子计算分析相结合的方法为鉴定农业动物重要经济性状的功能性分子标记提供了一条新的途径。

Maximizing seed yield is the ultimate breeding goal in important cereal crop species.  Seed set is a key developmental stage in the process of seed formation, which determines grain number, seed mass, and realized yield potential, and can be severely affected by abiotic and biotic stresses.  However, seed set can also be substantially reduced by genetic factors even under optimal fertilization conditions.  The underlying molecular genetic mechanisms are still obscure.  In this review, we elucidate the process of seed set of cereal crop species in detail, including development of floral structures, formation of viable gametes, double fertilization, seed development, and abortion.  We discuss how genetic and non-genetic factors affect seed set in different development stages.  Finally, we will propose novel strategies to study genetic mechanisms controlling seed set and exploit genetic resources to improve seed set in cereal crop species.

Soil moisture is the most critical limiting factor impacting yields of dryland winter wheat (Triticum aestivum L.) and it is strongly affected by tillage practice and sowing methods.  This study was to assess the link between sowing method and tillage practice during summer fallow and their subsequent effect on soil moisture and grain yield.  Furthermore, we sought to identify a more appropriate farming management practice for winter wheat production in Loess Plateau region of China.  The experiment was conducted from 2011 to 2013, using a two-factor split plot design, including subsoiling (SS) or no tillage (NT) during summer fallow for main plots, and conventional drill sowing (DS) or plastic film drill sowing (FM) for sub-plots.  Results showed that the maximum soil water storage (SWS) was under SS×FM treatment with values of 649.1 mm (2011–2012) and 499.4 mm (2012–2013).  The SWS during the 2011–2012 growing season were 149.7 mm higher than that in the 2012–2013 growing season.  And adoption of SS×FM significantly increased precipitation use efficiency (PUE) and water use efficiency (WUE) compared to other treatments for both seasons.  Moreover, adoption of SS×FM significantly increased yield by 13.1, 14.4, 47.3% and 25.9, 39.1, 35.7% than other three treatments during the two growing seasons, respectively.  In summary, combining subsoiling during summer fallow with plastic film drill sowing (SS×FM) increased SWS at sowing and effectively improved WUE, thus representing a feasible technology to improve grain yield of dryland winter wheat in the Loess Plateau of China.

Heat stress seriously affects wheat production in many regions of the world.  At present, heat tolerance research remains one of the least understood fields in wheat genetics and breeding and there is a lack of effective methods to quantify heat stress and heat tolerance in different wheat cultivars.  The objective of this study was to use various wheat cultivars to evaluate stress intensity (δ) and a new method for quantification of heat tolerance and compare this technique with three other currently utilized methods.  This new parameter for heat tolerance quantification is referred to as the heat tolerance index (HTI) and is an indicator of both yield potential and yield stability.  Heat treatments were applied in a controlled setting when anthesis had been reached for 80% of the wheat.  The stress intensity evaluation indicated heat shock was the main factor associated with kernel weight reduction while grain yield reduction was mainly associated with chronic high temperature.  The methods evaluation showed that a temperature difference of 5°C from natural temperatures was a suitable heat treatment to compare to the untreated controls.  HTI was positively correlated with yield under heat stress (r=0.8657, δ₂₀₁₀=0.15, in 2009–2010; r=0.8418, δ₂₀₁₁=0.20, in 2010–2011; P<0.01), and negatively correlated with yield reduction rate (r=–0.8344, in 2009–2010; r=–0.7158, in 2010–2011; P<0.01).  The results of this study validated the use of HTI and temperature difference control for quantifying wheat heat tolerance that included the yield potential and the stability of different wheat cultivars under heat stress.  Additionally, 10 wheat cultivars showed high HTI and should be further tested for their heat confirming characteristics for use in wheat heat tolerance breeding.

Founder parents have contributed significantly to the improvement of wheat breeding and production.  In order to investigate the genetic characteristics of founder parents and widely planted cultivars, Mazhamai (M), Biyumai (B) and six sibling lines (BM1–6) derived from the cross M×B were phenotyped for eight yield-related traits over multiple years and locations and genotyped using the the wheat 90K single nucleotide polymorphism (SNP) assay.  BM4 has been used as a founder parent, and BM1 has been widely planted, whereas BM2, 3, 5, and 6 have not been used extensively for breeding or planting in China.  Phenotypic comparisons revealed that BM4 and BM1 displayed a better overall performance than the other sibling lines.  BM1 showed higher thousand-grain weight than BM4, whereas BM4 exhibited lower coefficient of variation for most of the yield-related traits across different years and locations, indicating that BM4 was widely adaptable and more stable in different environments.  SNP analysis revealed that BM4 and BM1 inherited similar proportions of the M genome but are dissimilar to BM2, 3, 5, and 6.  Both BM1 and BM4 have specific alleles that differ from the other BM lines, and most of these alleles are concentrated in specific chromosomal regions that are found to associate with favorable QTLs, these SNPs and their surrounding regions may carry the genetic determinants important for the superior performance of the two lines.  But BM4 has more genetic diversity than BM1 with more specific alleles and pleiotropic regions, indicating that the genome of BM4 may be more complex than the other sibling lines and has more favorable gene resources.  Our results provide valuable information that can be used to select elite parents for wheat and self-pollinating crop breeding.

Simple sequence repeat (SSR) markers have been shown to be a powerful tool for varieties identification in plants.  However, SSR fingerprinting of sweetpotato varieties has been a little reported.  In this study, a total of 1 294 SSR primer pairs, including 1 215 genomic-SSR and 79 expressed sequence tag (EST)-SSR primer pairs, were screened with sweetpotato varieties Zhengshu 20 and Luoxushu 8 and their 2 F₁ individuals randomly sampled, and 273 and 38 of them generated polymorphic bands, respectively.  Four genomic-SSR and 3 EST-SSR primer pairs, which showed good polymorphism, were selected to amplify 203 sweetpotato varieties and gave a total of 172 bands, 85 (49.42%) of which were polymorphic.  All of the 203 sweetpotato varieties showed unique fingerprint patterns, indicating the utility of SSR markers in variety identification of this crop.  Polymorphism information content (PIC) ranged from 0.5824 to 0.9322 with an average of 0.8176.  SSR-based genetic distances varied from 0.0118 to 0.6353 with an average of 0.3100 among these varieties.  Thus, these sweetpotato varieties exhibited high levels of genetic similarity and had distinct fingerprint profiles.  The SSR fingerprints of the 203 sweetpotato varieties have been successfully constructed.  The highly polymorphic SSR primer pairs developed in this study have the potential to be used as core primer pairs for variety identification, genetic diversity assessment and linkage map construction in sweetpotato and other plants.

The combined use of chemical and organic fertilizers is considered a good method to sustain high crop yield and enhance soil organic carbon (SOC), but it is still unclear when and to what extent chemical fertilizers could be replaced by organic fertilizers.  We selected a long-term soil fertility experiment in Gongzhuling, Northeast China Plain to examine the temporal dynamics of crop yield and SOC in response to chemical nitrogen, phosphorus, and potassium (NPK) fertilizers and manure, applied both individually and in combination, over the course of three decades (1980–2010).  We aimed to test 1) which fertilizer application is the best for increasing both maize yield and SOC in this region, and 2) whether chemical fertilizers can be replaced by manure to maintain high maize yield and enhance SOC, and if so, when this replacement should be implemented.  We observed that NPK fertilizers induced a considerable increase in maize yield in the first 12 years after the initiation of the experiment, but manure addition did not.  In the following years, the addition of both NPK fertilizers and manure led to an increase in maize yield.  SOC increased considerably in treatments with manure but remained the same or even declined with NPK treatments.  The increase in maize yield induced by NPK fertilizers alone declined greatly with increasing SOC, whereas the combination of NPK and manure resulted in high maize yield and a remarkable improvement in SOC stock.  Based on these results we suggested that NPK fertilizers could be at least partially replaced by manure to sustain high maize yield after SOC stock has reached 41.96 Mg C ha^–1 in the Northeast China Plain and highly recommend the combined application of chemical fertilizers and manure (i.e., 60 Mg ha^–1).

Little is known about the muscle developmental patterns during embryonic to neonatal development in ducks. We investigated the developmental patterns in the lateral gastrocnemius muscles of Gaoyou and Jinding ducks differing in their muscle growth rates during the final stages of egg incubation and the first week after hatching. Expression of the MyoD gene was quantified by quantitative real-time PCR (qRT-PCR). The average cross-sectional area and diameter of the fibers increased from embryonic day 21 (E21), peaking at E27, and then declining slightly 7 d after hatching. The density of the fibers decreased initially but increased after hatching in both breeds and sexes. The within-breed variation in muscle fiber-type composition was greater than the average variation between the breeds. Overall, the percentage of type I fibers increased and that of type IIb fibers decreased consistently. However, the percentage of type IIa fibers was almost constant as development proceeded in both duck breeds. The profiles of MyoD mRNA expression were similar in both breeds, and a significantly positive relationship was observed between the expression of MyoD and the percentage of type IIb fibers. This study firstly revealed the characteristics of duck muscle development and differences between the two breeds differing in growth rates. Moreover, type IIb fibers might convert to type I fibers in the lateral gastrocnemius, while MyoD may potentially function in controlling the muscle fiber phenotype during the secondary myogenesis of muscle development.

   Searching alternative feed antibiotics is always a study hotspot in the field of animal production. In this study, the anti-pathogenic activities and probiotics stimulatory effects of 30 kinds of herbs were screened through Oxford cup method and Hungate roll method. 15 herbs showed significantly antibacterial activities (P<0.05) against Escherichia coli, Salmonella enteritidis, Salmonella typhimurium and Staphylococcus aureus. Seven herbs showed greatly stimulatory promoting effects on Lactobacillus acidophilus and Bifidobacterium longum. Finally, five herbs were combined for the developed formulation with selective antibacterial properties and they were Mume Fructus (35%), Isatidis Folium (25%), Moslae Herba (20%), Chrysanthemi Indici Flos (13%) and Bupleuri Radix (7%). The herbal formulation showed significantly antibacterial abilities against four pathogens and stimulatory promoting abilities on two probiotics in vitro and the equivalent activities in broiler chickens in vivo against E. coli and L. acidophilus. The toxicity study showed it had no toxicity, which indicated that it would be a kind of preferred candidate for an alternative antibiotic in future animal production.

  Calcineurin (Cn or CaN) is implicated in the control of skeletal muscle fiber phenotype and hypertrophy. However, little information is available concerning the expression of Cn in chickens. In the present study, the expression of two Cn subunit genes (CnAα and CnB1) was quantified by qPCR in the lateral gastrocnemius (LG, mainly composing of red fast-twitch myofibers), the soleus (mainly composing of red slow-twitch myofibers) and the extensor digitorum longus (EDL, mainly composing of white fast-twitch myofibers) from Qingyuan partridge chickens (QY, slow-growing chicken breed) and Recessive White chickens (RW, fast-growing chicken breed) on different days (1, 8, 22, 36, 50 and 64 days post-hatching). Although CnAα and CnB1 gene expressions were variable with different trends in different skeletal muscles in the two chicken breeds during postnatal growth, it is highly muscle phenotype and breed specific. In general, the levels of CnAα and CnB1 gene expressions of the soleus were lower than those of EDL and LG in both chicken breeds at the same stages. Compared between the two chicken breeds, the levels of CnAα gene expression of the three skeletal muscles in QY chickens were higher than those in RW chickens on days 1 and 22. However, on day 64, the levels of both CnAα and CnB1 gene expressions of the three skeletal muscles were lower in QY chickens than those in RW chickens. Correlation analysis of the levels of CnAα and CnB1 gene expressions of the same skeletal muscle showed that there were positive correlations for all three skeletal muscle tissues in two chicken breeds. These results provide some valuable clues to understand the role of Cn in the development of chicken skeletal muscles, with a function that may be related to meat quality.

The aim of this study was to investigate the feasibility of stimulating ovarian follicle development in order to improve fertility in water buffalo cows by immunization against inhibin. The experiment was carried out in early summer (May) and included 24 multi-parity crossbred Murrah-Swamp buffaloes that were divided into immunized (n=11) and control (n=13) groups. Each immunized cow was administered with a 2-mL immunogen of mineral oil adjuvant containing 2 mg of recombinant inhibin α-subunit fusion protein. The controls were treated with the adjuvant only. All animals received Ovsynch protocol treatment, starting on the day of the antigen administration, and they were artificially inseminated upon behavioral estrus. As a result, all of the immunized buffaloes generated antibodies against inhibin during the experimental period and had higher plasma concentrations of follicle-stimulating hormone (FSH), activin, and estradiol (E2) related to estrous expression. A higher proportion of immunized animals expressed estrus behavior than did the controls (72% vs. 30%, P<0.05). On average, inhibin-immunized buffaloes had significantly more large follicles (≥9 mm in diameter) than the controls (mean±SEM; 1.2±0.1 vs. 0.84±0.1, respectively; P<0.05) and a slightly higher mean total number of follicles (≥2 mm; 11.4±0.7 vs. 9.0±1.1, respectively; P=0.09) and small (2–4 mm) follicles (8.81±0.6 vs. 6.84±1.0, respectively; P=0.12). A higher percentage of cows ovulated in the immunized group than in the control group (91% (10/11) vs. 54% (7/13), respectively; P<0.05). Moreover, inhibin-immunized cows had slightly larger corpus luteum (CL) than the controls 9 days after ovulation and significantly higher (P<0.01) post-ovulation peak plasma progesterone (P4) concentrations. Immunization against inhibin also marginally increased the conception rate 42 days after insemination (45.8% vs. 15.4%; P>0.05). These results demonstrate that immunization against inhibin, coupled with the treatment with the Ovsynch protocol, can constitute a new technique to increase fertility in water buffalo cows.

SOM encodes a nucleus-localized CCCH-type zinc finger protein and negatively regulates seed germination in Arabidopsis thaliana. We have previously demonstrated that ectopic expression of SlABI3, an important transcription factor in abscisic acid (ABA) signaling pathway, resulted in alteration of SlSOM expression patterns in both leaf and seed of tomato. In this study, we aimed to elucidate the function of tomato SlSOM in regarding to seed germination and seedling development. Here, we constructed SlSOM over-expression vector pBI121-SOM driven by CaMV 35S promoter, and the recombinant plasmid was incorporated into wild-type tomato by the method of Agrobacterium tumefaciens-mediated transformation. The result showed that over-expression of SlSOM conferred enhanced responses to exogenous ABA application during seed germination and seedling development. In addition, ectopic expression of SlSOM resulted in the alteration of expression level of ABA/GA (gibberellins) metabolic genes, such as SlABA1, SlCYP707A1, SlGA3ox2, and SlGA2ox4, in both leaf and seed. The ABA anabolic gene SlABA1 and the GA catabolic gene SlGA2ox4 were up-regulated while the ABA catabolic gene SlCYP707A1 and the GA anabolic gene SlGA3ox2 were down-regulated. Compared to wild type, the expression level of SlABI5 was increased by about 40–50% in transgenic seeds while adding exogenous ABA treatment. These results support the notion that SlSOM inhibits seed germination by regulating ABA/GA metabolic genes and SlABI5 expression in Solanum lycopersicum.

Exotic plant invasion presents a serious threat to native ecosystem structure and function. Little is known about the role of soil microbial communities in facilitating or resisting the spread of invasive plants into native communities. The purpose of this research is to understand how the invasive annual plant Ambrosia artemisiifolia L. facilitates its competition capacity through changing the structure and function of soil microbial communities. The soil characteristics of different areas invaded by A. artemisiifolia were examined. Greenhouse experiments were designed to assess the effect of A. artemisiifolia invasion-induced changes of soil biota on co-occurring plant growth, and on the interactions between A. artemisiifolia and three co-occurring plant species. The results showed that the soil organic C content was the highest in heavily invaded sites, the lowest in native plant sites, and intermediate in newly invaded sites. Soil available N, P and K concentrations in heavily invaded site were 2.4, 1.9 and 1.7 times higher than those in native plant soil, respectively. Soil pH decreased as A. artemisiifolia invasion intensity increased, and was lower in invaded sites (heavily invaded and newly invaded) than in native plant sites. The soil microbial community structure was clearly separated in the three types of sites, and A. artemisiifolia invasion increased anaerobe, sulfate-reducing bacteria and actinomycete abundance. Soil biota of invaded sites inhibits growth of co-occurring plants (Galinsoga parviflora Cav., Medicago sativa L. and Setaria plicata (Lam.) T. Cooke.) compared to soil biota from un-invaded sites, but facilitates A. artemisiifolia growth and competition with co-occurring plants. A. artemisiifolia biomass was 50-130% greater when competing with three co-occurring plants, compared to single-species competition only (invasion by A. artemisiifolia alone), in heavily invaded soil. Results of the present study indicated that A. artemisiifolia invasion alters the soil microbial community in a way that favors itself while inhibiting native plant species, with measurable effects on performance of co-occurring plants.

Using homology cloning method, a heat shock transcription factor (Hsf) like gene, ZmHsf-like, was cloned from maize (Zea mays) leaves. Sequence analyses showed that the open reading frame (ORF) of the gene ZmHsf-like is 1404 bp long, encoding 467 amino acids. The sequence of amino acids encoded by ZmHsf-like contains the most conserved and typical DNA-binding domain of Hsf family. By bombardment into onion epidermis, we firstly found that the ZmHsf-like was subcellular-located in nucleus. NucPred analysis revealed there is a classic NLS of KKRR peptide in protein. Real-time PCR showed that ZmHsf-like gene expressed in leaves, stems and roots of maize seedlings under normal growth conditions, and the highest expression level was in roots, lower in leaves and the lowest in stems. The ZmHsf-like gene expression could be up-regulated by heat shock, PEG, ABA, and H2O2 in different degrees, among which the heat shock and ABA worked more efficiently. Obvious differences of the peak value and its corresponding time point of ZmHsf-like gene expression were observed among treatments. Experiments with inhibitor further suggested that the up-regulation ZmHsf-like gene expression of heat shock was H2O2-dependent while the induction of ZmHsf-like with PEG did not depend on the existence of H2O2. These results pointed out that ZmHsf-like gene probably regulates responsive reactions to abiotic stresses especially heat shock and drought through different signal transduction pathways.

Sweetpotato (Ipomoea batatas (L.) Lam.) breeding is challenging due to its genetic complexity. In the present study, interval mapping (IM) and multiple quantitative trait locus (QTL) model (MQM) analysis were used to identify QTLs for starch content with a mapping population consisting of 202 F1 individuals of a cross between Xushu 18, a cultivar susceptible to stem nematodes, with high yield and moderate starch, and Xu 781, which is resistant to stem nematodes, has low yield and high starch content. Six QTLs for starch content were mapped on six linkage groups of the Xu 781 map, explaining 9.1-38.8% of the variation. Especially, one of them, DMFN_4, accounted for 38.8% of starch content variation, which is the QTL that explains the highest phenotypic variation detected to date in sweetpotato. All of the six QTLs had a positive effect on the variation of the starch content, which indicated the inheritance derived from the parent Xu 781. Two QTLs for starch content were detected on two linkage groups of the Xushu 18 map, explaining 14.3 and 16.1% of the variation, respectively. They had a negative effect on the variation, indicating the inheritance derived from Xu 781. Seven of eight QTLs were co-localized with a single marker. This is the first report on the development of QTLs co-localized with a single marker in sweetpotato. These QTLs and their co-localized markers may be used in marker-assisted breeding for the starch content of sweetpotato.