世界范围内有各种品种、类型的鸡，它们的品种特征各不相同，是宝贵的遗传资源。目前，对影响这些鸡品种的特异性表型的遗传决定因素的研究还有待进一步加深。深入了解品种特异性表型变异的潜在遗传机制可以帮助育种者培育和改良鸡品种。本研究对7个来自山东省的本地品种共140只鸡和20只引进的隐性白羽鸡的全基因组进行了重测序。基于常染色体单核苷酸多态性(SNPs)的群体基因组比较结果揭示了鸡群基于地理距离的聚类模式。通过全基因组范围内的选择性清除分析，本研究确定了甲状腺刺激激素受体(TSHR，繁殖性状，生理节律)，红细胞膜蛋白带4.1 样 1 (EPB41L1，体型大小)和烷基甘油单加氧酶(AGMO，攻击行为)是主要候选的鸡品种特异性决定基因。此外，本研究利用机器学习分类模型，基于与品种特征显著相关的SNPs对鸡的品种进行判别，预测准确率为92%，可有效实现莱芜黑鸡的品种鉴定。本研究首次提供了山东地方鸡种的完整基因组数据，相关的分析揭示了山东地方鸡种的地理模式和鸡的品种特异性性状相关的潜在的候选基因。此外，本研究开发了一个基于机器学习的预测模型，使用SNPs数据进行品种判别，该部分内容为利用机器学习方法开发品种分子身份证提供了参考。本研究揭示的地方鸡品种遗传基础有助于更好地理解鸡资源特性的内在机制。

 

猪繁殖与呼吸综合征（Porcine reproductive and respiratory syndrome, PRRS）是猪传染性最强和致死性最高的病毒性疾病之一。尽管分化抗原簇163 (Cluster of differentiation 163, CD163) 蛋白被确定为介导PRRS病毒（Porcine reproductive and respiratory syndrome virus, PRRSV）感染的必需受体，但CD163参与感染的重要氨基酸残基仍不清楚。鉴定这些关键残基对于研究PRRSV的感染机制和制备抗PRRSV的基因编辑猪具有重要意义。对CD163结构的分析表明，CD163 SRCR5结构域内的配体结合口袋(ligand-binding pocket, LBP)(位于CD163的第487位到499位氨基酸)和loop 5–6（位于CD163的第544位到570位氨基酸）可能参与了PRRSV的感染。CD163 LBP位点特异性编辑猪可以完全抵抗PRRSV感染，但loop 5-6的破坏或缺失是否能抑制PRRSV的感染尚未报道。R561（第561位的精氨酸（R））位于loop 5-6内，R561A突变的PK-15细胞可以显著增强对PRRSV的抗感染能力，但定点编辑CD163 R561的猪肺泡巨噬细胞（porcine alveolar macrophages, PAMs）（PRRSV感染的靶细胞）或CD163 R561编辑猪能否抑制PRRSV的感染仍不清楚。这项研究中，我们首先利用CRISPR/Cas9介导的片段删除技术制备了CD163缺失40个氨基酸残基的永生化猪肺泡巨噬细胞（immortalized porcine alveolar macrophage, IPAM）细胞系，这40个残基位于CD163的第523位到562位氨基酸，这其中包含了R561和部分loop 5–6结构，该细胞系被命名为IPAM-CD163^△523-562。病毒感染实验表明，IPAM-CD163^△523-562可以完全抵抗 PRRSV的感染。同时，我们利用CRISPR/Cas9介导同源重组技术制备了携带CD163-R561A（CD163的561位精氨酸（R）被替换为丙氨酸（A））的基因编辑克隆猪，并分离得到原代CD163-R561A PAMs。PRRSV攻毒实验结果表明，与野生型的CD163-R561 PAMs相比，CD163-R561A PAMs 对PRRSV的易感性显著降低。以上研究结果表明，CD163的第523位到562位氨基酸中含有介导PRRSV感染的必需氨基酸残基，CD163 R561参与了PRRSV的感染过程，但它不是感染所必需的。这些位点可以作为了解PRRSV感染机制的新靶点，CD163-R561A猪也可作为培育抗PRRSV猪群体的育种材料。

苹果茎沟病毒 (apple stem grooving virus, ASGV) 是一种重要的潜隐类果树病毒，对柑橘、梨和苹果等多种果树的生产构成了严重的威胁。2018年，在中国南方广泛种植的黄金蜜柚 (Citrus grandis cv. Huangjinmiyou) 上观察到了严重的黄化、斑驳和花叶症状，推测其可能由病毒引起。取5株表现相关症状果树的叶片样品构建混库并送高通量测序分析，从其中鉴定到了3个ASGV变异体，通过RT-PCR和RACE技术验证了其基因组序列。序列分析显示，这3个变异体的基因组核苷酸序列一致性为81.03%–82.34%，其基因组结构与过往报道的侵染其它果树的变异体类似。基于病毒全基因组核苷酸序列和外壳蛋白氨基酸序列的系统发育分析显示，3个黄金蜜柚ASGV变异体分别与来自不同寄主和地区的ASGV变异体聚在一枝。重组分析显示，3个ASGV变异体可能来自于ASGV不同株系间的重组。在全国11个主要柑橘种植省份采集了507份黄金蜜柚样品进行RT-PCR检测发现，在每个省份表现上述相关症状的样品中，ASGV的检出率均在92.7%以上，而在40份没有症状的样品中，均未检测到ASGV。将其中6个省份的感病样品嫁接到ASGV的指示植物——Rusk枳橙上，新生的系统叶表现出典型的碎叶症状，进一步验证了黄金蜜柚中ASGV的侵染。进一步探究了病毒和症状与温度的关系，发现嫁接的感病黄金蜜柚样品在30°C–35°C条件下症状消失，同时RT-PCR也检测不到ASGV的存在。而后，再将其置于20°C–24°C的条件下一段时间后，黄金蜜柚症状恢复，且ASGV可以由RT-PCR检测到。本文揭示了黄金蜜柚黄化斑驳花叶病与ASGV侵染的相关性，并提示了该病害大面积流行的风险，为进一步的病害防控提供了相应参考。

2009年在中国首次发现了柑橘褪绿矮缩病毒（CCDaV），该病毒在云南瑞丽造成柠檬大量发病、减产，损失严重。目前，CCDaV在中国其它柑橘种植省份的发生分布和流行趋势尚不清楚。为了系统掌握CCDaV在中国的发生分布及其分子特性，本研究于2017-2019年，从中国11个柑橘主要生产省份采集了1,772份柑橘样品，通过PCR检测发现，采自广西省、云南省和广东省的134份柑橘样品感染了CCDaV。其中感病品种分别为红宝石蜜柚（50.8%）、泰国青柚（24.0%）、尤力克柠檬（20.8%）、墨西哥莱檬（20.0%）、塔希提莱檬（18.2%）和三红蜜柚（3.2%）。在采集的甜橙、宽皮柑橘、杂柑、枳、葡萄柚和金柑等柑橘类型样品中均没有检测出CCDaV。与前期的研究结果相比，CCDaV在中国的发生区域正在逐步扩大，且感病品种的种类也在增加。此外，CCDaV在红宝石蜜柚、泰国青柚和三红蜜柚新梢上产生的症状较其在尤力克柠檬上更为严重，除产生典型的“V”型叶，叶片扭曲、畸形，黄化外，CCDaV在上述3种柚类品种上还能产生严重的脉明症状。本研究选取了17个CCDaV毒株与GenBank数据库中已知的15个CCDaV毒株进行全系列分析，结果显示CCDaV的序列保守性高，所有 32个CCDaV毒株的核苷酸相似性大约为99%-100%。系统发育树分析表明，CCDaV毒株间的亲缘关系与其采样地和寄主存在相关性。根据地理来源和寄主种类的差异，CCDaV毒株被划分成了4个不同的类群，其中中国和土耳其的CCDaV毒株属于不同的类群。此外，还首次证明中国的CCDaV毒株可能存在多个起源中心，且部分毒株可能来自泰国。本研究结果为明确CCDaV在中国的发生分布、流行规律，以及遗传演化提供了重要的理论依据。

由于劳动力投入少、经济效益高，水稻直播已成为中国南方地区主要的种植方式。旱直播方式在单季水稻栽培技术方面运用广泛。然而，对早籼稻机械旱直播试验的研究还少有报导。通过两年大田间试验，以2个籼稻品种（中嘉早17和株两优819）为材料，研究旱直播、淹水直播和湿直播模式下的水稻倒伏特性和产量形成。结果表明，在旱直播方式下，株两优819和中嘉早17的年均产量分别比湿直播和淹水直播高14.42-26.34%和6.64-24.58%，这主要是由于穗数的提高。旱直播方式显著提高了早籼稻品种的出苗率，增加总干重和作物生长速率。同时，与淹水直播和湿直播相比，旱直播基部节间较短，茎粗和茎壁较厚，倒伏指数较低。尤其是旱直播提高了茎秆的抗倒伏能力。本研究结果表明，适宜的直播方式有利于提高早籼稻的产量和抗倒伏能力。

草地贪夜蛾于2018年12月入侵中国，2019和2020年分别在中国26和27个省（自治区、直辖市）发生112.5万公顷和127.8万公顷。玉米是受害最严重的作物，同时麦类等20余种其它农作物也受到危害。在研究明确草地贪夜蛾生物学习性、发生规律和危害特性的基础上，中国政府将草地贪夜蛾发生区域划分为西南华南周年繁殖区、江南江淮迁飞过渡区和黄淮海及北方重点防范区，实施分区治理策略；全国农技推广中心构建的全国草地贪夜蛾监测预警技术平台，可实时掌握县域水平的害虫发生信息；根据测报信息，基层政府组织植保队伍和农民采取化学防治、理化诱控和生物生态控制等措施及时开展防治工作。通过联防联控的组织模式，草地贪夜蛾的发生危害得到了有效控制，2019-2020年全国草地贪夜蛾发生区的总体产量损失低于5%，保障了玉米等作物的安全生产。本文也讨论了现阶段存在的问题及未来发展方向。

The effects of exogenous GSH (reduced glutathione) on photosynthetic characteristics, photosystem II efficiency, absorbed light energy allocation and the H₂O₂-scavenging system in chloroplasts of salt-stressed tomato (Solanum lycopersicum L.) seedlings were studied using hydroponic experiments in a greenhouse.  Application of exogenous GSH ameliorated saline-induced growth inhibition, the disturbed balance of Na⁺ and Cl⁻ ions and Na⁺/K⁺ ratios, and the reduction of the net photosynthetic rate (P_n).  GSH also increased the maximal photochemical efficiency of PSII (F_v/F_m), the electron transport rate (ETR), the photochemical quenching coefficient (q_P), and the non-photochemical quenching coefficient (NPQ).  In addition, GSH application increased the photochemical quantum yield (Y(II)) and relative deviation from full balance between the photosystems (β/α–1) and decreased the PSII excitation pressure (1–q_P) and quantum yield of non-regulated energy dissipation (Y(NO)) in leaves of salt-stressed tomatoes without BSO (L-buthionine-sulfoximine, an inhibitor of key GSH synthesis enzyme γ-glutamylcysteine synthetase) or with BSO.  Further, the addition of GSH depressed the accumulation of H₂O₂ and malondialdehyde (MDA), induced the redistribution of absorbed light energy in PSII reaction centers, and improved the endogenous GSH content, GSH/GSSH ratio and activities of H₂O₂-scavenging enzymes (including superoxidase dismutase (SOD), catalase (CAT), peroxidase (POD) and key enzymes in the AsA-GSH cycle and Grx system) in the chloroplasts of salt-stressed plants with or without BSO.  Therefore, GSH application alleviates inhibition of salt-induced growth and photosynthesis mainly by overcoming stomatal limitations, improving the PSII efficiency, and balancing the uneven distribution of light energy to reduce the risk of ROS generation and to mediate chloroplast redox homeostasis and the antioxidant defense system to protect the chloroplasts from oxidative damage.  Thus, GSH may be used as a potential tool for alleviating salt stress in tomato plants.

    A process-oriented methodology to conduct precise evaluation temporally and spatially on temperature suitability for potato growth was applied in China. Arable lands in China were gridded with 1 km×1 km geographic units, and potential potato phenology in each unit was automatically identified in terms of the potato planting initial temperature and effective accumulated temperature. A temperature thermal response coefficient model was used to compute a temperature suitability value for each day of potato phenology in each geographic unit. In addition, five temperature suitability ranking methods were applied to define suitable areas: (1) upper fourth quantile, (2) median, (3) expected value+1/4 standard deviation, (4) expected value+1/2 standard deviation, (5) expected value+1 standard deviation. A validation indicator was innovated to test the effectiveness of the five ranking methods. The results showed that from a strict degree point of view, the five methods sequence was as follows: 1=3>4>2>5, with a and c determined as the two best ranking methods. For methods 1 and 3, the suitable potato growing area was 1 of 57.76×10⁴ km². In addition, the suitable areas were spatially coincident with the main potato producing counties. The study output technically supports the proposal from China’s government that there is a large potential area to grow winter-ploughed potato in South China because the potential suitable area for growing potato is approximately 2×10⁷ ha. In southeast Heilongjiang and east Jilin, where it is hilly and mountainous, there are still some potentially suitable areas for potato growing accounting for nearly 2.32×10⁶ ha. The authors suggest to optimize the agricultural regionalization and layout in China and to adjust the cropping pattern structure.

The incorporation of straw in cultivated fields can potentially improve soil quality and crop yield. However, the presence of recalcitrant carbon compounds in straw slow its decomposition rate. The objective of this study was to determine the effects of different nitrogen sources, with and without the application of zinc, on straw decomposition and soil quality. Soils were treated with three different nitrogen sources, with and without zinc: urea (CO(NH2)2), ammonium sulfate ((NH4)2SO4), and ammonium chloride (NH4Cl). The combined treatments were as follows: maize (M) and wheat (W) straw incorporated into urea-, ammonium sulfate-, or ammonium chloride-treated soil (U, S, and C, respectively) with and without zinc (Z) (MU, MUZ, WU, WUZ; MS, MSZ, WS, WSZ; MC, MCZ, WC, WCZ, respectively); straw with zinc only (MZ, WZ); straw with untreated soil (MS, WS); and soil-only or control conditions (NT). The experiment consisted of 17 treatments with four replications. Each pot contained 150 g soil and 1.125 g straw, had a moisture content of 80% of the field capacity, and was incubated for 53 days at 25°C. The rates of CO2-C emission, cumulative CO2-C evolution, total CO2 production in the soils of different treatments were measured to infer decomposition rates. The total organic carbon (TOC), labile organic carbon (LOC), and soil microbial biomass in the soils of different treatments were measured to infer soil quality. All results were significantly different (P<0.05) with the exception of the labile organic carbon (LOC). The maize and wheat straw showed different patterns in CO2 evolution rates. For both straw types, Zn had a synergic effect with U, but an antagonistic effect with the other N sources as determined by the total CO2 produced. The MUZ treatment showed the highest decomposition rate and cumulative CO2 concentration (1 120.29 mg/pot), whereas the WACZ treatment had the lowest cumulative CO2 concentration (1 040.57 mg/pot). The addition of NH4Cl resulted in the highest total organic carbon (TOC) concentration (11.59 mg kg-1). The incorporation of wheat straw resulted in higher microbial biomass accumulation in soils relative to that of the maize straw application. The results demonstrate that mineral N sources can affect the ability of microorganisms to decompose straw, as well as the soil carbon concentrations.

Citrus tristeza virus (CTV) is one of the most important causal agents of citrus diseases and exists as numerous strains.CTV is replicated in phloem cells of plants within the family Rutaceae and is transmitted by a few of aphid species. CTVepidemics have caused death of millions of citrus trees in many regions all over the world, where the sour orange (Citrusaurantium) was used as rootstock. Also the production of grapefruit (C. paradisi) and sweet orange (C. sinensis) hasbeen affected by CTV strains. CTV gives uplift to three prominent syndromes, namely quick-decline (tristeza), stempittingand seedling-yellows. The disease is graft-transmissible in nature but not seed-transmitted. However, the tristezadisease in most citrus groves was a man-made problem created by the desire of horticulturists to introduce cultivars fromother citrus growing areas. The utmost importance of the disease called for review articles in numbers of plant protection,epidemiology books, citriculture and proceedings. This review collects the information with respects to disease history,distribution host range, virus isolates association, identification and detection, transmission and management; especiallyon the current status of CTV prevailing and controlling in Pakistan. It provides valuable information for CTV disease andits controlling approaches.

Since May 2006, a highly pathogenic porcine reproductive and respiratory syndrome virus (HP-PRRSV) variant characterizedby 30 amino acids deletion within its NSP2-coding region emerged and caused extensive economic losses to China’s pigindustry. To investigate the in vivo pathogenicity and immune responses of the newly emerging PRRSV, 3 groups of 60-d-old conventional piglets were inoculated intranasally with a representative strain of the HP-PRRSV variant HuN4 with3 different infection doses (3×103-3×105 TCID50). The results revealed that the virus variant caused severe disease inpiglets and the significant clinical characteristics consisted of persistently high fever (41.0-41.9ºC) and high morbidity andmortality (60-100%), the marked clinical signs of PRRS and severe histopathogenic damages in multiple organs. It inducedrapid and intense humoral immune responses and seroconversion was detected in most infected pigs at 7 d post-infection(DPI). The virus vigorously replicated in vivo and the highest virus average titer was 9.7 log copies mL-1 serum at 7 DPI.Elevated levels of IFN-γ and IL-10 cytokine production in serum in this study were also observed. Taken together, ourresults demonstrated that the HP-PRRSV variant HuN4 strain is highly pathogenic for piglets and suitable to be a referencestrain of highly virulent PRRSV for evaluating the efficacy of the new vaccines.