阐明作物耐受低氮胁迫的生理和分子机制，促进氮素从衰老叶片向新叶的转移对提高芸薹属的氮素利用效率至关重要。谷氨酰胺合成酶（GS）参与植物叶片蛋白降解过程中释放的铵的重新同化过程，是我们研究的重要基因。在本研究中，我们通过水培试验发现了2个对低氮胁迫响应有差异的基因型芥菜：氮高效基因型芥菜（H141）和氮低效基因型芥菜（L65）。各项生理指标表明H141号芥菜氮素利用效率高的生理原因是它的地上部拥有较低的硝酸盐含量，较高的铵盐、游离氨基酸含量以及NR和GS活性。全基因组重测序数据表明在H65和L141之间有5,880个与NUE相关的基因存在多态性。这些基因参与了氨基酸代谢、碳水化合物代谢和能量代谢。单倍型分析结果表明在芥菜群体中BjuB05.GS1.4存在两种单倍型，Hap1和Hap2在5’非翻译区（UTR）和3’UTR的调控区以及内含子中具有多个单核苷酸多态性或插入/缺失，并且Hap1芥菜群体的地上部NUE显著低于Hap2。这两种单倍型导致芥菜不同遗传群体的地上部NUE存在差异，并与当地土壤氮含量有关，这表明它可能有助于芥菜适应不同的地理环境。因此，我们的研究结果揭示了不同芥菜NUE基因型的生理和分子机制，并证明了在芥菜中进行NUE育种的巨大潜力。

全球变暖引起气候变化，严重影响植物生长发育，并对粮食安全构成威胁。植物本身具有对适宜温度的响应能力(如热形态发生)，并能承受一定范围的高温胁迫。在分子水平上，许多小分子在维持生长和防御机制之间的平衡发挥着关键作用，通过微调对外部刺激的响应来确保作物的最佳产量。因此，了解植物响应热应激的分子机制，解析植物适应热胁迫的的生物过程变得至关重要。在本综述中，我们概述了植物热响应基因网络，论述了植物如何感知高温并启动细胞和代谢反应，最终使其能够适应不利的生长条件。最后，我们还对植物生长及对热应激响应之间的权衡作出讨论，提出调控植物响应热应激的调节网络，这也将为全面挖掘耐热候选基因并应用于农业生产提供帮助。

为了研究沙门菌三种主要毒力岛SPIs（SPI-1、2和3）对其生理学、致病性和免疫原性的影响，本研究通过构建改进的λ-Red同源重组系统，以肠炎沙门菌SM6野毒株为亲本制备了三种主要SPIs（SPI-1、2和3）的单缺失（SM6ΔSPI1, SM6ΔSPI2, SM6ΔSPI3）和三缺失突变体（SM6ΔSPI1&2&3）；对突变体的生长和稳定性进行检测；采用扫描电镜观察菌体形态；利用Biolog微生物鉴定系统检测碳源代谢情况；检测突变体对Caco-2细胞的粘附和侵袭能力；以1×10⁷ CFU剂量腹腔注射7日龄来航鸡于注射后第2、4、8天(dpi)检测突变体在肝脏和脾脏内的定殖情况；另外，按1×10⁷ CFU剂量将各突变体分别于7、21和35日龄腹腔免疫后在首免2、3、4、5、6周（wpi）收集血清检测特异性IgG水平，并于42日龄腹腔注射1×10⁹ CFU剂量的SM6野毒株，于攻毒后第7和14天检测血液中细胞因子水平，同时收集脾细胞检测CD3⁺CD4⁺和CD3⁺CD8⁺比率，对免疫和攻毒后鸡只的临床表现和组织病理损伤进行打分，对各突变体的免疫效力进行评价。结果表明，单缺失突变体的表面表现出更粗糙的质地，并似乎被一层透明的胶体包裹，而与亲本菌株相比，三缺失突变体的形态保持不变。SPI突变体的碳代谢谱发生了深刻的变化，在95个碳源中的30个碳源（主要是碳水化合物）中观察到了显著且具有统计学意义的变化（30个碳来源中的17个）。此外，与亲本菌株相比，四种突变体对Caco-2细胞的粘附能力显著降低。此外，突变体SM6ΔSPI1和SM6ΔSPI1&2&3的入侵能力显著降低，而SM6ΔSPI3和SM6△SPI2的入侵能力不同程度地增强。重要的是，四个突变体中没有一个在雏鸡中引起任何临床症状。然而，它们确实在脾脏和肝脏短暂定植。值得注意的是，SM6ΔSPI1&2&3突变体在感染后8天内从脾脏和肝脏中迅速清除，并且在器官中没有观察到显著的病理变化。此外，当受到攻击时，突变体免疫组的抗体水平显著增加，CD3⁺CD4⁺和CD3+CD8⁺亚群发生变化，SM6ΔSPI1&2&3免疫鸡血清中的IL-4和IFN-γ细胞因子水平超过其他组。总之，四个SPI突变体的成功构建为进一步探索SPI的致病（包括代谢）机制和开发安全有效的减毒沙门氏菌活疫苗或载体奠定了基础。

高谷物日粮诱导的亚急性瘤胃酸中毒（SARA）会损害反刍动物的瘤胃上皮屏障功能，但SARA是否会持续性损害瘤胃上皮屏障的形态结构和功能还尚不清楚。本研究旨在以泌乳山羊为动物模型，研究SARA是否对瘤胃上皮的形态结构、通透性及参与上皮屏障功能的关键基因表达具有持续性影响。选取12只安装有永久性瘤胃瘘管的泌乳中期奶山羊，随机分为对照组（Ctrl，n=4）和SARA组（n=8），对照组试验动物饲喂NFC/NDF比为1.40的基础饲粮，SARA组依次饲喂NFC/NDF比为1.40、1.79、2.31和3.23四种饲粮诱导试验动物发生SARA。SARA诱导成功后从SARA组中随机选取4只患病动物让其自由采食混合粗饲料4周使其恢复，即post-SARA组。采用pH值监测系统连续监测瘤胃pH值以判定SARA的严重程度。采集瘤胃腹囊上皮组织，利用透射电镜、尤斯灌流室、PCR和Western blot等先进技术检测瘤胃上皮的形态结构和功能。结果表明：与对照组相比，（1）SARA组瘤胃上皮乳头长度、宽度、表面积和角质层厚度显著增加(P<0.05)，棘基层厚度和上皮总厚度则显著降低(P<0.05)。post-SARA组这些参数则趋向于恢复到对照组水平(P>0.05)。同时透射电镜结果显示，SARA减少了瘤胃上皮紧密连接数量，加宽了上皮细胞之间的间隙。（2）SARA组和post-SARA组瘤胃上皮短路电流（Isc）、组织导电性（Gt）以及辣根过物氧化酶（HRP）通过瘤胃上皮的流速均显著增加(P<0.05)，这表明SARA可引起瘤胃上皮通透性持续升高，进而导致其屏障功能长期受损。（3）SARA组和post-SARA组瘤胃上皮紧密连接蛋白CLDN1, OCLN and ZO-1的mRNA和蛋白表达量均极显著下调(P<0.01)。由此可见，SARA可导致瘤胃上皮屏障结构和功能持续受损，这与瘤胃上皮紧密连接蛋白表达下调密切相关，而且瘤胃上皮屏障功能的恢复滞后于形态结构的恢复。

中国板栗是世界上重要的坚果树种。我国板栗种质资源十分丰富，但在其资源利用与保护方面仍受到很大的限制。本研究利用18个荧光SSR标记对146份板栗资源进行了指纹图谱的构建，并解析了板栗品种群间的亲缘关系和筛选了板栗资源的核心种质。结果表明，每个基因座的平均等位基因数(Na)和多态性信息含量(PIC)分别为8.100和0.622，18个SSR标记表现出高的多态性。利用这些高效的标记，本试验成功构建了146份板栗资源的有唯一匹配的指纹图谱，并从中筛选出了7个SSR标记作为核心标记，实现了板栗资源的快速鉴定。对5个板栗品种群遗传关系进行研究，可知，中国板栗品种群被划分为3个类群，分别是类群I(华北品种群和西北品种群)、类群II(长江中下游品种群)和类群III(西南品种和东南品种群)。最后，我们选取了具有代表性的45个中国板栗资源作为核心种质。本研究为板栗资源的鉴定和品种群的亲缘关系提供了重要信息，为今后板栗的高效育种奠定基础。

Bulk-SSR method was used to analyze the genetic diversity of 44 open-pollinated varieties collected from Henan, Shandong, Shanxi, and Jilin provinces and Guangxi Zhuang Autonomous Region, China using 70 pairs of SSR primers. The purposes of this study were to (1) compare the genetic diversity among 44 Chinese maize open-pollinated varieties; (2) estimate the minimum number of alleles for construction of a stable dendrogram; and (3) trace the genetic relationships among local germplasm from different regions of China. In total, these 70 SSR primers yielded 292 alleles in 176 samples (4×44) analyzed. The number of alleles per locus was 4.17 on average and ranged from 2 to 8. The highest number of alleles per open-pollinated variety (55.25) was detected in Shanxi germplasm, which indicated that open-pollinated varieties from Shanxi possessed the largest genetic diversity among those from the five locations. The correlation coefficients between different genetic similarity matrices suggested that 200 alleles were sufficient for analysis of the genetic diversity of these 44 open-pollinated varieties. The cluster analysis showed that 44 open-pollinated varieties collected from three growing regions in China were accurately classified into three groups that were highly consistent with their geographic origins, and there is no correlation between GS and geographic distance in this study.

The problem of associating the agricultural market names on web sites with their locations is essential for geographical analysis of the agricultural products. In this paper, an algorithm which employs the administrative ontology and the statistics from the search results were proposed. The experiments with 100 market names collected from web sites were conducted. The experimental results demonstrate that the algorithm proposed obtains satisfactory performance in resolving the problem above, thus the effectiveness of the method is verified.

Classical swine fever caused by Classical swine fever virus (CSFV) is a serious problem for swine industries in developing countries, which successful control of the disease have been relying on vaccination. However, classical swine fever still occurs in some immunized swine herds for various reasons. In this study, we conducted animal experiments to examine the influence of single or mixed infection with Porcine parvo virus (PPV), Pseudorabies virus (PRV) and Porcine reproductive and respiratory syndrome virus (PRRSV) on the protective immunity induced by the Lapinized hog cholera virus (HCLV) vaccine and the pathogenicity of CSFV. In experiment 1, pigs were first inoculated with PPV, PRV or PRRSV, then immunized with HCLV, and finally challenged with a highly virulent CSFV Shimen strain. All of the pigs immunized with HCLV survived after the challenge, while all of the pigs in the non-immunized control group died after the challenge. The pigs in the group immunized with HCLV did not show any clinical symptoms of classical swine fever and were negative with CSFV after the challenge. The pigs infected with the non-CSFV before HCLV immunization did not display any clinical symptoms after the challenge with CSFV Shiman strain, but 11 of the 12 pigs were positive with CSFV. In experiment 2, pre-infections with PPV, PRV, and PRRSV were followed by inoculation with a low-virulence CSFV strain (CSFV 39), and then the pigs were challenged with the CSFV Shimen strain. Infections by either PPV, PRV or PRRSV did not enhance the virulence of CSFV-39, but pigs infected by a mixture of the 3 viruses developed clinical symptoms after inoculation with CSFV-39. The mixed infection also increased mortality caused by the challenge with the CSFV Shimen strain. Together, these results showed PPV, PRV and PRRSV infections in pigs can reduce the efficacy of the HCLV vaccine and enhance the pathogenicity of CSFV, which may partly explain the immunization failure against CSFV in some swine herds.