茶树是中国主要经济作物之一，安徽省茶树栽培历史悠久具有丰富的种质资源和遗传多样性。茶树的高度杂合性导致其种质资源收集、管理及保护等方面工作进展缓慢，并且长期保存管理成本高，因此提高安徽省茶树种质资源的管理质量和效率，构建核心种质迫在眉睫。本研究从安徽省6个主要产茶地区收集了573份有代表性的茶树，基于60对SSR分子标记进行系统发育关系、群体结构和主坐标分析。聚类结果显示，安徽省573份茶树被分为5个类群，这些类群分布地区与收集样品的地理位置相关，聚类结果与PCoA的分群结果也基本一致。最后，我们构建了一个由115份茶树品种组成的核心种质，占原始种质的20%。核心种质中观察到的等位基因数(Na)具有90.9%的保留率，并且核心种质和原始种质的香农信息指数(I)及其他遗传多样性参数之间没有显著性差异。所有代表性茶区均保留了部分代表性品种，其中黄山地区保留了39份茶树，占核心种质的33.9%；金寨县保留了10份茶树，占核心种质的8.9%。PCoA结果表明构建的核心种质均匀的分布在收集的安徽省茶树种质中，说明构建的核心种质能够代表安徽省茶树种质的遗传多样性。本研究对安徽省茶树种质资源的高效保存和利用具有一定的参考价值。

本研究通过室内试管石英砂培养的方法，测试香蕉穿孔线虫对本氏烟草的侵染致病过程和规律，明确了香蕉穿孔线虫侵染本氏烟草根系主要在根系皮层寄生，导致皮层细胞分解、组织腐烂。通过采用不同致病型和不同寄主来源的香蕉穿孔线虫群体对本氏烟草侵染致病的接种条件进行测定，以及对发病植株的症状表现、受害严重度和线虫繁殖率等致病性相关因子的评估，确定了香蕉穿孔线虫与本氏烟草互作研究的最佳测试条件和结果评估标准，从而建立了本氏烟草作为寄主的香蕉穿孔线虫致病性测定方法：（1）在玻璃培养试管中装入约占高度1/3 干燥的石英砂并灭菌两次；（2）将20天苗龄的本氏烟草幼苗移栽到试管中，在25±1℃条件下培养定植10 天；（3）以150条/株的接种虫量将香蕉穿孔线虫的雌虫接种到烟草根际；（4）在接种线虫30天后检测植株发病严重度、生长量和线虫繁殖量。本研究还采用该方法对致病型和寄主来源不同的8个香蕉穿孔线虫种群的致病性强弱进行了测定，证明了该方法的可行性。本研究结果为将本氏烟草作为香蕉穿孔线虫与植物互作研究的模式植物提供了依据和方法，为香蕉穿孔线虫致病性及其与寄主互作分子机制研究提供了新途径，对利用本氏烟草作为模式寄主研究香蕉穿孔线虫的致病机制和防治方法具有重要意义。

Plant structures and chemicals, which are developed from the shoot apical meristem (SAM), form the main barriers to insect feeding.  A plant chimera containing cells of different genetic origins in the SAM will be morphologically and chemically different compared with the parents and thus may result in differential resistance to herbivores.  In this study, we explore if particular elements of plant resistance are localized in one of the layers of SAM; the replacement of one cell layer in a chimera may be linked to change of a single resistance trait to herbivores.  The morphology and glucosinolate profiles of two periclinal chimeras (labeled as TTC and TCC, respectively) and grafted parents tuber mustard (labeled as TTT) and red cabbage (labeled as CCC) were compared and the performance of whitefly (Bemisia tabaci) in host selection, oviposition preference and development were assessed under controlled conditions.  Both chimeras possessed leaf trichomes as parent tuber mustard TTT, however, TTC had significantly more trichomes than TCC and parent TTT.  Leaf wax content of both chimeras was intermediate between the two parents.  Five aliphatic and two indole glucosinolates were detected in both chimeras, whereas three aliphatic glucosinolates (3-methyl-sulfinylpropyl, 4-methyl-sulfinylbutyl and 2-hydroxy-3-butenyl) were not detected in tuber mustard, and one aliphatic glucosinolate (3-butenyl) was not detected in red cabbage.  Unexpectedly for a chimera, the quantities of two aliphatic glucosinolates (3-methyl-sulfinylpropyl and 4-methyl-sulfinylbutyl) in both TTC and TCC were 3- to 5-fold higher than parents.  In olfactory preference assays, B. tabaci showed preference to CCC, followed by TCC, TTC and TTT, and number of eggs laid showed the same pattern: CCC>TCC>TTC>TTT.  Interestingly, more whiteflies landed on TTT plants than the other three types in a free choice experiment and the developmental duration from egg to adult was the shortest on TTT and increased in the order TTT<TTC<TCC<CCC.  Our results indicate plant defenses traits of leaf waxes, trichomes and glucosinolates are not controlled by one cell layer of SAM, but are influenced by interactions amongst cell layers.  The overall findings suggest that periclinal chimera systems can be a valuable approach for the study of plant-insect interactions and may also be useful for future resistance breeding. 

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.