在高等植物中，茎尖分生组织以规则的间隔（叶序）和时间（叶间期）生成侧生器官。对叶序和叶间期相关突变体分析将加深对植物茎尖结构发育机制的理解。本研究中，扬农啤5号EMS诱变获得一个出叶速率变快、节间数目增多和矮化突变体，命名为mnd8^ynp5。利用图位克隆的方法，mnd8基因定位于5H染色体长臂6.7kb的基因组区间。序列分析表明，HORVU5Hr1G118820在第一个外显子953位发生了C到T单核苷酸突变，导致编码蛋白第318位氨基酸由丙氨酸（Ala）变为缬氨酸（Val）。HORVU5Hr1G118820作为MND8基因的候选基因，编码514个氨基酸，包含两个多药和有毒化合物挤压结构域（MATE），与玉米Bige1高度同源，具有通过控制叶片起始速率来调控植物发育的保守功能。现代大麦品种单倍型分析表明，Hap-1是被全世界大麦育种中应用的主要单倍型。总之，mnd8^ynp5作为HORVU5Hr1G118820基因的新等位基因，调控了大麦叶间期和矮秆多节表型。

剪接因子Prp6是剪接三聚体U4/U6.U5中的关键蛋白，在人类细胞和裂殖酵母中，它也是调控前体mRNA剪接的激酶Prp4的底物。前期研究发现引起小麦赤霉病的禾谷镰孢菌FgPrp6蛋白序列的自发突变（角突变）可以部分恢复Fgprp4突变体的表型。禾谷镰孢菌FgPrp4激酶调控剪接效率，其敲除突变体生长缓慢且丧失产孢、有性生殖和致病能力。为了进一步探索FgPrp6与激酶FgPrp4的关系，本研究通过对随机收集的240株Fgprp4角突变子的FgPRP6基因进行PCR产物测序，鉴定了20个角变子中的12个突变。其中3个突变位点在FgPrp6蛋白的N端结构域和HAT重复结构域的连接处，7个突变位点位于前两个HAT重复区域。对角变子的转录组数据分析结果表明FgPrp6上不同位置的角突变对Fgprp4突变体前体mRNA剪接缺陷的恢复程度不同。通过在野生型菌株中转入FgPrp6^E308K-GFP载体或在内源FgPrp6上原位引入R230H突变，同时敲除FgPRP4的方法证实FgPrp6上的E308K或R230H都可以抑制Fgprp4。本研究利用co-IP和BiFc的方法证明禾谷镰孢菌的FgPrp6和激酶FgPrp4可以在体内互作，并进一步利用磷酸化抗体检测体内FgPrp6磷酸化水平的方法实验证明FgPrp6为FgPrp4的底物。通过将FgPrp6上保守的Prp4磷酸化位点和预测的磷酸化位点突变为A的方法验证这些位点的功能，结果表明T261，T219&T221和T199&T200对FgPrp6在菌落生长和有性生殖中的功能无关紧要，但是对其在侵染植物阶段的功能至关重要。扫描电镜和共聚焦显微镜观察发现它们主要在禾谷镰孢菌侵染生长，如侵染垫的形成和在植物细胞间的扩展中发挥作用。通过对野生型禾谷镰孢菌、Fgprp6/FgPRP6^Δ199-221-GFP或Fgprp6/FgPRP6^Δ250-262-GFP侵染三天的小麦麸片的转录组数据分析禾谷镰孢菌的前体mRNA剪接缺陷发现Fgprp6/FgPRP6^Δ199-221-GFP和Fgprp6/FgPRP6^Δ250-262-GFP菌株中各有28%和35%的内含子剪接具有缺陷，推测这种剪接缺陷是突变体侵染生长缺陷的原因。该研究为将来进一步解析禾谷镰孢菌前体mRNA剪接调控及剪接与致病性的关系奠定了基础。

水稻干尖线虫可侵染水稻、大豆、棉花等多种作物，给农业生产造成严重损失。丝氨酸羧肽酶（SerineCarboxypeptidases，SCP）是植物寄生线虫致病的一个关键因子，但丝氨酸羧肽酶在水稻干尖线虫中的致病机制并不清楚。本研究以水稻干尖线虫为对象，利用原位杂交、qRT-PCR、瞬时表达、真核表达以及基因沉默等方法对水稻干尖线虫丝氨酸羧肽酶（AbSCP1）的功能进行研究。研究得出，AbSCP1基因全长1425 bp，编码氨基酸长度为474aa。AbSCP1编码蛋白具有信号肽、无跨膜结构域，与香蕉穿孔线虫SCP蛋白的序列相似性为67%。不同龄期水稻干尖线虫AbSCP1的qPCR分析得出，该基因在幼虫中的表达量最高，其次是雌虫、雄虫和卵。通过原位杂交证实，AbSCP1在水稻干尖线虫的食道腺中表达。使用昆虫细胞表达系统获得了AbSCP1蛋白，通过与特异性底物反应证实了该蛋白的羧肽酶活性，并得出了酶促反应最适的pH为4.5。使用烟草瞬时表达系统表达AbSCP1，在烟草细胞核中出现强烈的特异荧光信号，说明AbSCP1被定位在植物细胞核中。使用RNAi研究AbSCP1对水稻干尖线虫致病力、繁殖力的影响。结果得出，水稻干尖线虫取食AbSCP1特异的dsRNA 24 h后，AbSCP1的表达量显著下降。使用基因沉默后的线虫分别接种水稻和灰葡萄孢，分别统计水稻的发病等级和线虫数。结果表明，AbSCP1被沉默后，水稻干尖线虫的致病力、繁殖率均显著下降。本研究首次在水稻干尖线虫中明确了SCP是一类可被分泌到寄主细胞核中发挥作用的蛋白酶类效应子，在线虫寄生寄主过程中起到重要作用。本研究的成果将为以AbSCP1为靶标开发高效、安全的水稻干尖线虫防治措施奠定基础。

Ten populations of Radopholus similis from different ornamental hosts were tested for their parasitism and pathogenicity to water spinach (Ipomoea aquatic), malabar spinach (Basella rubra), and squash (Cucurbita moschata) in pots. The results showed all three plants were new hosts of R. similis. Growth parameters of plants inoculated with nematodes were significantly lower than those of healthy control plants. All R. similis populations were pathogenic to the three plants, but pathogenicity differed among populations from different hosts. The same R. similis populations also showed different pathogenic effects in the three different plants. RadN5 population from Anthurium andraeanum had the highest pathogenicity to the three studied plants. RadN1 from A. andraeanum had the lowest pathogenicity to squash and RadN7 from Chrysalidocarpus lutesens had the lowest pathogenicity to water spinach and malabar spinach. R. similis is usually associated with root tissues, but here we report that it could be found to move and feed in the stem bases of all three studied plants. Sequence and phylogenetic analyses of DNA markers of the 18S rRNA, 28S rRNA, ITS rRNA, and mitochondrial DNA gene sequences of ten R. similis populations revealed significant genetic diversity. RadN5 and RadN6 populations from anthurium showed a close genetic relationship and could be distinguished from other populations by PCR-RFLP. At the same time, RadN5 and RadN6 populations were the most pathogenic to three studied plants. These results confirm the existence of large biological variability and molecular diversity among R. similis populations from the same or different hosts, and these characteristics are related to pathogenic variability.

In order to establish double antibody sandwich enzyme-linked immunosorbent assay (DAS-ELISA) for detection of duck or goose flavivirus, polyclonal antibody against the flavivirus strain JS804 in geese and monoclonal antibody against the E protein of flavivirus strain JS804 in geese were used as the capture antibody and detection antibody, respectively. The optimal dilution of the capture antibody and detecting antibody capable of detecting the flavivirus strain JS804 in geese were 1:3 200 and 1:160 in the check-board titration, respectively. The reaction time of sample was 1 h, and the optimal working dilution of HRP-labeled goat-anti-mouse IgG was 1:10 000. The positive standard value was 0.247 (OD450 nm). The geese flavivirus could be detected at a minimal concentration of 1.875 μg mL-1. The ELISA had no cross-reaction with Newcastle disease virus (NDV), Avian influenza virus (AIV), Infectious bronchitis virus (IBV), Infectious bursal disease virus (IBDV), Duck hepatitis virus (DHV), and Gosling plague virus (GPV). Twenty clinical samples were detected by the DAS-ELISA and RT-PCR respectively, with the agreement rate of 75%. The results revealed that the DAS-ELISA possessed favorable specificity and higher sensitivity, indicating a suitable method for rapid detection of the duck or goose flavivirus.

Insecticidal activities of the petroleum ether-, chloroform-, ethyl acetate-, and water-soluble fractions of the methanolicextract of Ficus sarmentosa var. henryi were assayed against Musca domestica adults. The chloroform- and ethyl acetatesolublefractions were the most active with 92.6 and 88.9% mortalities (24 h after treatment) respectively. Therefore, thetwo fractions were combined and four compounds, isolated from the fractions by activity-guided fractionation, wereelucidated as 7-hydroxycoumarin, apigenin, eriodictyol, and quercetin by spectroscopic method and displayed excellentinsecticidal activities against adults of M. domestica and 4th instar larva of Aedes albopictus. Among those, 7-hydroxycoumarin showed the strongest insecticidal activities with lethal concentrations (LC50) values of 72.13 μg g-1sugar and 4.87 μg mL-1 (48 h after treatment) against the test insects respectively. The cytoxicities of these compounds onBTI-Tn-5B1-4 cell were also investigated for the insecticidal mechanism and found that quercetin represented superiorinhibitory activity with MTT assay and reactive oxygen species (ROS) against BTI-Tn-5B1-4 cell, but slightly weaker thanthat of the positive control (azadirachtin) and significantly greater than the negative control (DMSO only). Meanwhile,eriodictyol demonstrated the strongest effect on the mitochondrial membrane potentials (MMP). In conclusion, based ontheir comparative toxicities to commercial insecticides and their cytotoxic effects, some of the compounds from theF. sarmentosa have potential as botanical insecticides.