Ca²⁺离子在维持细胞壁以及细胞膜的完整性中具有重要作用，是植物生长和发育中必不可少的矿质营养元素之一。解析Ca²⁺离子在糖代谢和脂代谢中的作用能够为理解棉花纤维快速伸长阶段细胞膜和细胞壁的动态变化提供有意义的参考。本研究利用胚珠培养系统发现缺Ca²⁺会促进纤维和胚珠细胞的膨大，但同时也会诱导组织的褐化。RNA-seq差异表达基因分析发现缺Ca²⁺使细胞处于一个较高的氧化态，并且激活与糖代谢和脂代谢相关的基因的表达。尤其以糖酵解途径变化最为显著，其代谢途径中的9个酶相关的基因上调表达，缺Ca²⁺处理细胞中的葡萄糖含量显著下降，改变了糖酵解途径的流动。低K⁺能够恢复缺Ca²⁺诱导糖酵解途径相关基因的表达以及葡萄糖的含量。采用电喷雾电离串联质谱技术检测了不同Ca²⁺、K⁺离子处理条件下细胞中脂质组成分的动态变化。缺Ca²⁺处理细胞中自由脂肪酸（FA）、二酰甘油（DAG）和糖脂含量降低，三酰甘油（DAG）磷脂酰乙醇胺（PE）、磷脂酰甘油（PG）、磷脂酰胆碱（PC）含量增加。低K⁺与缺Ca²⁺的互作信号能够恢复FA、磷脂、糖脂含量至正常水平，有效缓解缺Ca²⁺效应。本研究通过在转录和代谢水平的比较分析，揭示了Ca²⁺和K⁺信号互作在维持纤维快速伸长过程中糖酵解和脂代谢中发挥着重要作用。

施肥是提升土壤肥力促进作物增产的有效措施，长期不同施肥对土壤培肥的效果差别很大，依托中国农科院红壤实验站双季稻田连续38年不同施肥定位试验，研究了7种不同施肥处理CK（不施肥）；NPK（化学氮、磷、钾肥料）；M（腐熟牛粪）；NPKM（化学氮、磷、钾和牛粪）；NPM（化学氮、磷和牛粪）；NKM（化学氮、钾和牛粪）；PKM（化学磷、钾和牛粪）对水稻产量、稻田土壤肥力与养分表观平衡的影响。结果表明，各处理水稻年均产量由高到低为NPKM、NPM、NKM、PKM、M、NPK、CK，范围在6214-11562 kg hm²。长期有机无机配施处理（NPKM、NPM、NKM、PKM）较NPK的增产率分别为：22.58%、15.35%、10.53%、4.41%。长期有机无机配施处理（NPKM、NPM、NKM、PKM）的土壤有机碳、全氮、有效氮、速效钾含量均显著高于CK和NPK，其中有机肥配施氮磷肥处理的NPKM、NPM、PKM土壤全磷和有效磷含量显著高于CK、NPK；NPKM处理的水稻年均产量（11562 kg hm²）、有机碳（20.88 g kg^-1）、土壤全氮（2.30 g kg^-1）、全磷（0.95 g kg^-1）、全钾（22.5 g kg^-1）、有效磷含量（38.94 mg kg^-1）均为各处理中最高，NKM处理土壤碱解氮含量（152.4mg kg^-1）和速效钾含量（151.00 mg kg^-1）为各处理最高。氮、磷施用量的增加导致土壤中氮、磷养分出现盈余，但NPKM处理相比其他处理能够有效降低盈余量；各处理土壤中钾素均表现为亏缺。相关性分析表明土壤SOC、TN、AN、TP、AP含量均与水稻产量显著相关（P<0.05），相关系数分别为0.428、0.496、0.518、0.501和0.438。本研究表明，相比单施化肥，长期有机肥配施化肥通过提升土壤肥力，促进土壤养分平衡，显著增加水稻产量，其中有机肥配施氮磷钾肥(NPKM)对于土壤肥力和水稻产量的提升效果最好。

非洲猪瘟（ASF）的持续流行严重威胁全球养猪业的健康发展。该病目前缺乏可应用于临床的疫苗和药物，因此，早期的精准检测对于ASF的有效防控至关重要。p30蛋白在病毒感染早期表达，免疫原性较好且诱导产生抗体水平较高，这些特性使其成为较为理想的非洲猪瘟病毒（ASFV）检测靶点之一。本研究以原核表达的p30蛋白为免疫原，制备了两株可稳定分泌针对ASFV p30蛋白的单克隆抗体（mAb）细胞株，分别命名为4F2和7F3。利用Western blotting和间接免疫荧光实验鉴定两株单克隆抗体均能识别病毒感染。亚型鉴定结果显示，4F2和7F3的重链分别为IgG1和IgG2b，轻链均为κ链。随后，通过原核表达一系列截短p30蛋白鉴定4F2和7F3识别的抗原表位。经5轮截短和Western blotting实验鉴定，最终确定4F2和7F3识别的最短抗原表位分别为¹¹⁸SFETL¹²²和⁷⁶EHQAQEEWNMILHV⁸⁹。在此基础上，进一步分析两个抗原表位在不同毒株p30蛋白序列中的保守性。序列比对结果表明，GenBank数据库中所有p30蛋白序列均包含¹¹⁸SFETL¹²² ，而另一抗原表位⁷⁶EHQAQEEWNMILHV⁸⁹则在非洲以外地区分离的毒株中保守。本研究制备的两株单克隆抗体及鉴定的抗原表位可为检测方法的开发提供材料和基础，同时也可为病毒致病机理和免疫机制等基础研究提供工具。

研究播期和生态点对半冬小麦产量的影响对小麦产量提高具有重要意义。本研究旨在探讨稻-麦轮作条件下播期和生态点对小麦产量以及相关气候资源的影响。试验以两个半冬性小麦品种为材料，分别在东海县和建湖县开展，共设置6个播期。第一播期(S1)基本苗300×10⁴ ha^-1，每推迟一个播期(S2-S6)基本苗分别增加10%。结果表明，播种期的推迟，导致整个生育期天数缩短、有效积温和累计太阳辐射降低。S2~S6产量较S1分别降低了0.22～0.31t ha^-1、0.5～0.78t ha^-1、0.86～0.98t ha^-1、1.14～1.38t ha^-1和1.36～1.59t ha^-1。同一播期，随着生态点北移，生育天数增加，日均温和有效积温降低，累积辐射增加。结果表明，相同播期，东海县的产量比建湖县低0.01 ~ 0.39 t hm ^{- 2}。有效积温、累积辐射与产量呈显著正相关。日均温与产量呈显著负相关。籽粒产量下降的主要原因由于日均温的升高和有效积温的降低导致穗粒数和千粒重下降引起的。

谷类/豆类间作已在世界范围内被广泛采用，以提高可持续农业系统中的作物生产力。在不同的间作组合中，谷子/花生间作可以适应大部分缺水地区。然而，关于谷子/花生间作与单作在不同施氮水平下的产量性状和氮素利用效率差异的研究较少。本研究旨在确定谷子/花生间作的产量优势、经济效益以及适宜的氮肥用量。采用三种种植模式（单作谷子、单作花生和谷子/花生间作）和四种施氮量（0、75、150和225 kg ha^-1）进行了为期两年的大田试验。结果表明，间作系统的土地当量比（LER）和净效应（NE）在施氮量为150 kg ha^-1时达到两年来的最高值（LER两年平均为1.04，NE分别为0.347 Mg ha^-1）。谷子是间作系统中的优势作物（谷子与花生的种间相对竞争能力（Amp）>0，竞争比率（CRmp）>1），单作在施氮量为225 kg ha^-1，间作为150 kg ha^-1时谷子产量最高。不同种植模式的氮利用效率（NUE）两年均在施氮量为150 kg ha^-1时达到最高。间作结合施氮150 kg ha^-1时净收益最高，两年平均为2791 $ ha^-1，效益成本比为1.56。因此，从经济和农业可持续发展的角度来看，150 kg N ha^-1施氮量的谷子/花生间作似乎是替代谷子或花生单作的一个有推广价值的选择。

水稻是中国主要粮食作物之一，世界性三大稻田恶性杂草之一的杂草稻对中国水稻生产的危害时有报道。然而，由于缺乏系统的调查研究，中国杂草稻的总体发生情况和形态类型的分布模式仍不清晰。为了揭示中国杂草稻的发生与危害情况，自2009年至2016年采用七级目测法对中国六个稻作区的999个稻田样点进行了田间调查。结果表明在387个样点中有杂草稻发生，杂草稻整体发生率约为39%。杂草稻综合草害指数在50%以上的样点主要从江苏、黑龙江、宁夏和广东辐射到华东、东北、西北和华南稻作区。通过2017年和2019年的同质园试验对调查过程中采集的287个杂草稻种群的45个形态特征进行了多元分析。结果表明，中国杂草稻存在丰富的形态学变异度和多样性，其形态学特征与原生境的经度、纬度、海拔、气温日较差、气温年较差、生育期的最低温、最高温、降雨量等地理气候因子具有显著的相关性。基于45个形态学性状的聚类分析将287个中国杂草稻种群分为三组：第一组为多分蘖强生长势型杂草稻，籼型，主要分布于江苏；第二组为大叶片型杂草稻，以籼型为主，生长势强，粒型优势弱于第三类杂草稻但强于第一组杂草稻，主要分布在我国的华东、华南、西南地区以及华中南部地区；第三组为大籽粒弱生长势型杂草稻，以粳型为主，主要分布在我国东北、华北、西北等北方地区。三组杂草稻多数无芒且具有黄色颖壳和红色果皮，多个叶型、株型等相关的营养性状以及产量、籽粒形态、穗型相关的生殖性状均存在着显著差异。综上，部分中国稻田已被杂草稻严重侵染，中国杂草稻具有地理、气候和栽培稻类型依赖的形态生物型分化。这暗示了我们需要重视杂草稻对水稻生产的危害，需采取综合防治策略来防控杂草稻。

猪的呼吸道是多种病原微生物的定殖场所，包括常见的四种猪源支原体，分别是猪肺炎支原体（Mhp），猪鼻支原体（Mhr），猪絮状支原体（MF）和猪滑液支原体（MHS）。猪源支原体主要寄居于猪气管黏膜表面，最具代表性的Mhp是引起猪气喘病的主要病原，并易与其他猪呼吸道病原混合或继发感染，引发猪呼吸道疾病综合征，使得感染猪产生慢性持续性呼吸系统疾病，给养猪业带来巨大的经济损失。沿着猪呼吸道上皮细胞的纤毛的黏附是猪源支原体成功感染的前提。猪原代气管上皮细胞（PTEC）是研究包括猪源支原体的各种猪呼吸道病原发病机制的合适模型，但原代PTEC细胞短暂的寿命极大地限制了其应用前景。因此，构建永生化的猪气管上皮细胞，对包括Mhp在内的所有猪源支原体等猪呼吸道病原，具有较高的应用价值。

我们首先提供了详细的分离和培养原代PTEC的方法步骤。随后通过用含有人端粒酶逆转录酶（hTERT）的重组构建的质粒pEGFP-hTERT转染原代PTECs，通过两轮G418的抗性筛选，建立永生化的猪气管上皮细胞系（hTERT-PTECs），并可传代至60代以上。通过比较原代与永生化细胞的上皮细胞表面标志物角蛋白18的表达，细胞周期，细胞生长曲线，端粒酶活性，染色体核型分析，端粒酶基因的蛋白质印记检测，软琼脂和裸鼠成瘤试验，增殖能力等相关基因的定量PCR检测，不仅证实了永生化细胞具备了原代细胞的形态及功能特性，与原代PTECs相比，hTERT-PTEC也具有更长的寿命，更高的端粒酶活性和增殖活性。裸鼠体内未表现出恶性表型，表明该细胞系不具有致瘤性。将不同的猪源支原体菌株感染hTERT-PTECs，通过颜色变化单位CCU₅₀黏附率的定量计算，hTERT-PTECs对所有猪源支原体易感，且原代和永生化细胞之间的黏附能力无显著差异。而对于代表性的Mhp，DNA拷贝定量实时PCR测定，间接免疫荧光测定和蛋白质印迹分析表明hTERT-PTECs能够粘附不同毒力的Mhp菌株。总之，与原代PTECs类似，hTERT-PTECs可以广泛用作猪源支原体的粘附细胞模型，并可用于多种猪呼吸道病原体的感染研究。

地下水资源紧缺是华北平原冬小麦生产面临的一个严峻的挑战，急需先进的节水技术在冬小麦生产上的应用。为了探讨微喷灌技术在冬小麦生产上的节水潜力，我们设置了五个处理，传统畦灌TF1（拔节期和开花期分别灌溉75 mm灌水量）；微喷灌MSI1（拔节期、开花期和灌浆中期分别微喷30 mm灌水量）; 微喷灌MSI2（起身期、拔节期、开花期和灌浆中期分别微喷30 mm灌水量）；微喷灌MSI3（起身期、拔节期、孕穗期、开花期和灌浆中期分别微喷30 mm灌水量）；微喷灌MSI4（返青期、起身期、拔节期、孕穗期、开花期和灌浆中期分别微喷30 mm灌水量），于2012-2015三个生长季通过大田试验进行了研究。研究结果表明，与TFI相比，MSI1和MSI2的水分利用效率分别增加了22.5和16.2%，同时分别降低耗水量17.6和10.8%。在不考虑降雨年型的情况下，与常规畦灌TFI相比，MSI1或MSI能够在降低20-40%灌溉水的前提下保证冬小麦稳产或显著增产。与TFI相比，MSI3的产量和水分利用效率也分别提高了4.6%和11.7%。微喷灌可以实现少量多次的灌溉，降低了土壤的紧实度并有利于小麦根系的下扎，进而有利于关键生育期光合同化物的生产。总之，与TF1相比，MSI1和MSI2能够在降低灌溉用水20-40%的前提下实现稳产或增产，这将为华北平原冬小麦节水高效生产提供一定的技术支撑。

Available irrigation resources are becoming increasingly scarce in the North China Plain (NCP), and nitrogen-use efficiency of crop production is also relatively low. Thus, it is imperative to improve the water-use efficiency (WUE) and nitrogen fertilizer productivity on the NCP. Here, we conducted a two-year field experiment to explore the effects of different irrigation amounts (S60, 60 mm; S90, 90 mm; S120, 120 mm; S150, 150 mm) and nitrogen application rates (150, 195 and 240 kg ha^–1; denoted as N1, N2 and N3, respectively) under micro-sprinkling with water and nitrogen combined on the grain yield (GY), yield components, leaf area index (LAI), flag leaf chlorophyll content, dry matter accumulation (DM), WUE, and nitrogen partial factor productivity (NPFP). The results indicated that the GY and NPFP increased significantly with increasing irrigation amount, but there was no significant difference between S120 and S150; WUE significantly increased first but then decreased with increasing irrigation and S120 achieved the highest WUE. The increase in nitrogen was beneficial to improving the GY and WUE in S60 and S90, while the excessive nitrogen application (N3) significantly reduced the GY and WUE in S120 and S150 compared with those in the N2 treatment. The NPFP significantly decreased with increasing nitrogen rate under the same irrigation treatments. The synchronous increase in spike number (SN) and 1 000-grain weight (TWG) was the main reason for the large increase in GY by micro-sprinkling with increasing irrigation, and the differences in SN and TGW between S120 and S150 were small. Under S60 and S90, the TGW increased with increasing nitrogen application, which enhanced the GY, while N2 achieved the highest TWG in S120 and S150. At the filling stage, the LAI increased with increasing irrigation, and greater amounts of irrigation significantly increased the chlorophyll content in the flag leaf, which was instrumental in increasing DM after anthesis and increasing the TGW. Micro-sprinkling with increased amounts of irrigation or excessive nitrogen application decreased the WUE mainly due to the increase in total water consumption (ET) and the small increase or decrease in GY. Moreover, the increase in irrigation increased the total nitrogen accumulation or contents (TNC) of plants at maturity and reduced the residual nitrate-nitrogen in the soil (SNC), which was conducive to the increase in NPFP, but there was no significant difference in TNC between S120 and S150. Under the same irrigation treatments, an increase in nitrogen application significantly increased the residual SNC and decreased the NPFP. Overall, micro-sprinkling with 120 mm of irrigation and a total nitrogen application of 195 kg ha–1 can lead to increases in GY, WUE and NPFP on the NCP.

Tillage represents an important practice that is used to dynamically regulate soil properties, and affects the grain production process and resource use efficiency of crops. The objectives of this 3-year field study carried out in the Huang-Huai-Hai (HHH) Plain of China were to compare the effects of a new deep vertical rotary tillage (DVRT) with the conventional shallow rotary tillage (CT) on soil properties, winter wheat (Triticum aestivum L.) grain yield and water and nitrogen use efficiency at different productivity levels, and to identify a comprehensive management that optimizes both grain yield and resource use efficiency in the HHH Plain. A split-plot design was adopted in field experiments in the winter wheat growing seasons of 2016–2017 (S1), 2017–2018 (S2) and 2018–2019 (S3), with DVRT (conducted once in June 2016) and CT performed in the main plots. Subplots were treated with one of four targeted productivity level treatments (SH, the super high productivity level; HH, the high productivity and high efficiency productivity level; FP, the farmer productivity level; ISP, the inherent soil productivity level). The results showed that the soil bulk density was reduced and the soil water content at the anthesis stage was increased in all three years, which were due to the significant effects of DVRT. Compared with CT, grain yields, partial factor productivity of nitrogen (PFP_N), and water use efficiency (WUE) under DVRT were increased by 22.0, 14.5 and 19.0%. Path analysis and direct correlation decomposition uncovered that grain yield variation of winter wheat was mostly contributed by the spike numbers per area under different tillage modes. General line model analysis revealed that tillage mode played a significant role on grain yield, PFP_N and WUE not only as a single factor, but also along with other factors (year and productivity level) in interaction manners. In addition, PFP_N and WUE were the highest in HH under DVRT in all three growth seasons. These results provided a theoretical basis and technical support for coordinating the high yield with high resource use efficiency of winter wheat in the resource-restricted region in the HHH Plain of China.

Northeast China (NEC) is one of the major maize production areas in China. Agro-climatic resources have obviously changed, which will seriously affect crop growth and development in this region. It is important to investigate the contribution of climate change adaptation measures to the yield and resource use efficiency to improve our understanding of how we can effectively ensure high yield and high efficiency in the future. In this study, we divided the study area into five accumulated temperature zones (ATZs) based on growing degree days (GDD). Based on the meteorological data, maize data (from agro-meteorological stations) and the validated APSIM-Maize Model, we first investigated the spatial distributions and temporal trends of maize potential yield of actual planted cultivars, and revealed the radiation use efficiency (RUE) and heat resource use efficiency (HUE) from 1981 to 2017. Then according to the potential growing seasons and actual growing seasons, we identified the utilization percentages of radiation (P_R) resource and heat resource (P_H) for each ATZ under potential production from 1981 to 2017. Finally, we quantified the contributions of cultivar changings to yield, P_R and P_H of maize. The results showed that during the past 37 years, the estimated mean potential yield of actual planted cultivars was 13 649 kg ha^–1, ranged from 11 205 to 15 257 kg ha^–1, and increased by 140 kg ha^–1 per decade. For potential production, the mean values of RUE and HUE for the actual planted maize cultivars were 1.22 g MJ^–1 and 8.58 kg (°C d)^–1 ha^–1. RUE showed an increasing tendency, while HUE showed a decreasing tendency. The lengths of the potential growing season and actual growing season were 158 and 123 d, and increased by 2 and 1 d per decade. P_R and P_H under potential production were 82 and 86%, respectively and showed a decreasing tendency during the past 37 years. This indicates that actual planted cultivars failed to make full use of climate resources. However, results from the adaptation assessments indicate that, adoption of cultivars with growing season increased by 2–11 d among ATZs caused increase in yield, P_R and P_H of 0.6–1.7%, 1.1–7.6% and 1.5–8.9%, respectively. Therefore, introduction of cultivars with longer growing season can effectively increase the radiation and heat utilization percentages and potential yield.

Received  19 April, 2017    Accepted  9 May, 2017

© 2018, CAAS. All rights reserved. Published by Elsevier Ltd.
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A total of 50 endophytic bacterial isolates were obtained from Kobreasia capillifolia at alpine grasslands in the Eastern Qilian Mountains on the Tibetan Plateau in China.  Based on the sequencing and phylogenetic analysis of 16S rDNA genes, all isolates phylogenetically related closely to Bacillus, Acinetobacter, Stenotrophomonas, Brevundimonas, Arthrobacter, Curtobacterium, Paenibacillus, Plantibacter, Promicromonospora, Serratia, and Microbacterium, among which Bacillus was the predominant genus (47.8% of the total number of endophytic isolates).  These isolates possessed different biological functions.  In 50 endophytic bacteria, 42 isolates produced indole acetic acid (IAA) on King medium.  There were seven isolates showing potency of mineral phosphate solubilization in Pikovaskaia’s (PKO) liquid medium.  Seven isolates exhibited antagonistic effect against Fusarium avenaceum, Colletotrichum coccodes and Phoma foveata.  This was the first report on diversity and plant growth promotion of endophytic bacteria from K. capillifolia on alpine grassland in the Eastern Qilian Mountains, Chain.  It is essential for revealing the relationship among plant, microorganism, and the special environment because the potential function of endophytic bacteria made a contribution to the interactions of plants and endophytic bacteria.

    Pepper (Capsicum spp.) is an important vegetable crop in the world. Now the pepper in China contributes one-third of the world’s peppers production. Genetic diversity of the pepper germplasm of China is expected interesting to know. To explore the structure of genetic diversity in Chinese pepper germplasm resources and possible relationship with cultivar types or geographic origin, we sampled and compared 372 GenBank pepper accessions (local cultivars and landraces) from 31 provinces, autonomous regions and municipalities of China and 31 additional accessions from other countries. These accessions were genotyped using 28 simple sequence repeat (SSR) markers spanning the entire pepper genome. We then investigated the genetic structure of the sampled collection using model-based analysis in STRUCTURE v2.3.4 and examined genetic relationships by the unweighted pair-group method of mathematical averages (UPGMA) in MEGA. In addition to geographic origin, we evaluated eight plant and fruit traits. In total, 363 alleles were amplified using the 28 SSR primers. Gene diversity, polymorphism information content and heterozygosity of the 28 SSR loci were estimated as 0.09–0.92, 0.08–0.92 and 0.01–0.34, respectively. The UPGMA cluster analysis clearly distinguished Capsicum annuum L. from other cultivated pepper species. Population structure analysis of the 368 C. annuum accessions uncovered three genetic groups which also corresponded to distinct cultivar types with respect to the plant and fruit descriptors. The genetic structure was also related to the geographic origin of the landraces. Overall results indicate that genetic diversity of Chinese pepper landraces were structured by migration of genotypes followed by human selection for cultivar types in agreement with consumption modes and adaptation to the highly diversified agro-climatic conditions.

Fruit set and development are affected by many phytohormones, including gibberellin.  Little is known regarding molecular mechanism underlying gibberellin mediated fruit set and development especially in Capsicum.  Three gibberellin receptors, CaGID1b.1, CaGID1b.2 and CaGID1c, and a DELLA protein, CaGAI, have been identified in Capsicum annuum L.  During the fruit development, the expression level of CaGID1c was low, and the expression fold change is mild.  However, CaGID1b.1 and CaGID1b.2 were relatively higher and more acute, which indicates that CaGID1b.1 and CaGID1b.2 may play an important role in fruit pericarp, placenta and seed.  Ectopic expressions of CaGID1b.1, CaGID1b.2 and CaGID1c in Arabidopsis double mutant gid1a gid1c increased plant height, among which CaGID1b.2 had the most significant effect; CaGAI reduced plant height in double mutant rga-24/gai-t6, having a similar function to AtGID1 and AtGAI in stem elongation.  Yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BiFC) assays indicated that CaGID1b.1 and CaGID1b.2 interact with CaGAI in a GA-dependent manner, while CaGID1c interacts with CaGAI in a GA-independent manner.  Our study reveals the key elements during gibberellin signaling in Capsicum and supports the critical importance of gibberellin for Capsicum fruit set and development.

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.

Low light stress is one of the most important factors affecting photosynthesis and growth in winter production of cucumber (Cucumis sativus L.) in solar greenhouses in northern China. Here, two genotypes of cucumber (Deltastar and Jinyan 2) are used to determine the effect of low light stress on Rubisco expression and photosynthesis of leaves from emergence to senescence. During leaf development, the net photosynthetic rate (PN), stomatal conductance (gs), Rubisco initial activity and activation state, transcript levels of rbcL and rbcS, and the abundance of rbcL and rbcS DNA in these two genotypes increase rapidly to reach maximum in 10-20 d, and then decrease gradually. Meanwhile, the actual photosystem II efficiency (ФPSII) of cucumber leaves slowly increased in the early leaf developing stages, but it declined quickly in leaf senescent stages, accompanied by an increased non-photochemical quenching (NPQ). Moreover, PN, gs, initial Rubisco activity, and abundance of protein, mRNA and DNA of Rubisco subunits of leaves grown under 100 μmol m-2 s-1 are lower, and require more time to reach their maxima than those grown under 600 μmol m-2 s-1 during leaf development. All these results suggest that lower photosynthetic capacity of cucumber leaves from emergence to senescence under low light stress is probably due to down-regulated Rubisco gene expression in transcript and protein levels, and decreased initial and total activity as well as activation state of Rubisco. Deltastar performs better than Jinyan 2 under low light stress.

It is of great importance to solve the threats induced by cadmium pollution on crops. This paper examined the effect of biochar on cadmium accumulation in japonica rice and revealed the mechanism underlying the response of protective enzyme system to cadmium stress. Biochar derived from rice straw was applied at two application rates under three cadmium concentrations. Shennong 265, super japonica rice variety, was selected as the test crop. The results indicated that cadmium content in above-ground biomass of rice increased with increasing soil cadmium concentrations, but the biochar application could suppress the accumulation of cadmium to some extent. Under high concentrations of cadmium, content of free proline and MDA (malondialdehyde) were high, so did the SOD (superoxide dismutase), POD (peroxidase) and CAT (catalase) activity in the flag leaf of rice. However, the protective enzyme activities remained at low level when biochar was added.

Based on the sequence of a novel expressed sequence tag (EST), the full-length cDNA of 1 017 nucleotides was cloned from Brassica napus cv. Xiangyou 15 through rapid amplification of cDNA ends (RACE). The gene was designated as Bnhol34 (HQ585980), encoding a protein of 338 amino acids. BLAST analysis showed no high degree of sequence identity to any known gene. The calculated molecular weight of the Bnhol34 protein was 36.23 kDa, and the theoretical isoelectric point was 8.74. The Bnhol34 was also cloned from a high oleic acid mutant 854-1 through homologous cloning. There was no difference between the two Bnhol34 genes. Bnhol34 was localized in a tissue-specific manner in B. napus, and its expression level was about eight-fold greater in Xiangyou 15 seeds than in 854-1. The promoter region sequences of Bnhol34 were then isolated from Xiangyou 15 and 854-1, and a 93-bp deletion was found to occur in the Bnhol34 promoter region of 854-1. Three abscisic acid-responsive cis-elements (ABRE) were identified in the promoter region of Xiangyou 15. Real-time PCR analyses revealed that exogenous abscisic acid increased Bnhol34 expression by about four-fold in Xiangyou 15 seeds, yet did not change Bnhol34 expression in 854-1. It appeared that Bnhol34 might be abscisic acid insensitive in 854-1.

Low temperature and high salinity are the major abiotic stresses that restrict cucumber growth and production, breeding materials with multiple abiotic resistance are in greatly need. Here we investigated the effect of introducing the LOS5 gene, a key regulator of ABA biosynthesis in Arabidopsis thaliana, under the stress-responsive RD29A promoter into cucumber (Cucumis sativus L. cv. S516). We found that T1 RD29A-LOS5 transgenic lines have enhanced tolerance to cold and salt stresses. Specifically, transgenic lines exhibited dwarf phenotypes with reduced leaf number, shorter internode, decreased length of the biggest leaf, fewer female flowers, shorter fruit neck and lower vitamin C (Vc). The increased cold tolerance can be reflected from the significantly decreased cold index, the reduced electrolyte leakage index and the MDA content upon cold treatment as compared to those in the control. This may result from the accumulation of internal ABA, soluble sugars and proline, and the enhanced activities of protective enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT) in the transgenic lines. Under salt treatment, the transgenic lines exhibited increased germination index, vigor index, more lateral roots and increased root fresh weight. Moreover, RD29A-LOS5 transgenic plants displayed quicker responses in salt stress than that in low-temperature stress.

Low light stress is one of the main limiting factors which influence the production of sweet pepper under protected cultivation in China. In this experiment, two genotypes of sweet pepper, ShY (low light-tolerant genotype) and 20078 (low light-sensitive genotype), were used to study the effects of low light (photosynthetic photon flux density, PPFD was 75- 100 μmol m-2 s-1, control 450-500 μmol m-2 s-1) on photosynthesis during leaf development. The result indicated that under low light chlorophyll content, net photosynthetic rate (PN), photosynthetic apparent quantum efficiency ( i) and carboxylation efficiency (CE) of sweet pepper leaves increased gradually and decreased after reaching the maximum levels. The time to reach the peak values for all the above parameters was delayed, whereas the light compensation point (LCP) decreased gradually along with leaf expansion. The decrease in maximum quantum yield of PS II (Fv/Fm) was not observed at any stages of the leaf development under low light condition, but the actual PS II efficiency under irradiance ( PS II) was lower accompanied by an increased non-photochemical quenching (NPQ) in young and/or old leaves compared with mature leaves. The antenna thermal dissipation (D) was a main way of heat dissipation when young leaves received excessive light energy, while the decline in photosynthetic function in senescence leaf was mostly owing to the decrease in carbon assimilation capacity, followed by a significantly increased allocation of excessive energy (Ex). Compared with 20078, ShY could maintain higher PN, PS II and lower QA reduction state for a longer time during leaf development. Thus, in ShY photosynthetic efficiency and the activity of electron transport of PS II were not significantly affected due to low light stress.

CatSper is a unique Ca2+ channel-like protein family exclusively expressed in the testis and sperm, and plays important roles in sperm motility, capacitation, acrosome reaction and sperm-egg interactions. Here we studied the mechanism of regulation of CatSper2-dependent Ca2+ influx, extracellular and intracellular Ca2+ on sperm hyperactivated motility. The siRNA duplexes were transfected into the sperm cells by electroporation (EP) to silence the expression of CatSper2. The results for targeted disruption of CatSper2 showed the highest silence efficiency 77.7% (P<0.05), the hyperactivated sperm rate calculated by computer-assisted semen analysis (CASA) analysis of interferenced sperm was significantly lower 11.1% than the control 99.2%. Flow cytometry (FCM) detection of the intracellular Ca2+ concentration of interferenced sperm was 50 nmol L-1 higher than the normal. It was remarkably lower than hyperactivated sperm with 200-1 000 nmol L-1 (P<0.05). It was not sufficient to evoke hyperactivation. To trigger hyperactivation, the sperm were incubated in 50 μmol L-1 thimerosal or 5 mmol L-1 procaine, it sharply increased the intracellular Ca2+ via two different channels. CASA and FCM detection indicated that intracellular Ca2+ is required for initiating hyperactivation while extracellular Ca2+ is essential to maintain the process. We concluded that to mediate sperm hyperactivation, it is essential to inhibit Ca2+ peak present with targeted disruption of CatSper2 expression. This provides important prospective for further exploration of signal channel of sperm hyperactivated motility, potential factors for male infertility and provide further reference to the exploration of male contraceptive drug targets of male reproduction.