由寄生疫霉（Phytophthora parasitica）引起的柑橘根腐病是柑橘生产上普遍发生、对柑橘危害较为严重的一种病害。本研究的目的是建立一种简易快速的结合侧流层析技术判定结果的重组酶聚合酶扩增（lateral flow strip-based recombinase polymerase amplification, LF-RPA）方法检测寄生疫霉，为诊断和防治寄生疫霉引起的柑橘根腐病提供技术支撑。以Ypt1基因为检测的靶标序列，通过多序列比对分析，设计寄生疫霉的特异性引物和探针，建立并优化LF-RPA检测方法，并与简易核酸提取技术相结合，对该检测方法的特异性、灵敏度和实际应用效果进行评估。对LF-RPA体系中的温度、引物和探针比例、时间进行了优化，使得LF-RPA在40°C孵育温度下反应20分钟后即可肉眼判断检测结果。特异性试验中，LF-RPA能特异性地检测出不同来源的寄生疫霉，而其它亲缘关系相近的卵菌病原菌均未检测出。灵敏度试验结果显示，LF-RPA的最低检测灵敏度为1 pg。为了使LF-RPA检测方法更适宜基层使用，对四种不同的简易核酸提取技术进行了比较评估，发现基于PEG-NaOH的简易核酸提取技术更适合本研究。将LF-RPA与PEG-NaOH核酸提取技术相结合，不需要特定的仪器设备，只需要能维持40°C的保温杯，即可在30分钟内完成从发病植株的核酸提取到结果判定的整个检测过程。利用该方法，成功地从接种寄生疫霉的柑橘叶片、枝条和果实上检测出寄生疫霉；此外也从田间采集的10份柑橘发病样品中检测出其中3份样品含有寄生疫霉本研究成功建立了一种针对寄生疫霉的LF-RPA快速检测方法，该方法与简易核酸提取技术相结合，非常适宜于基层使用，为柑橘根腐病的快速诊断奠定了技术基础。

For the scientific management of farmland, it is significant to understand the spatio-temporal variability of soil organic matter and to study the influences of related factors. Using geostatistical theory, GIS spatial analysis, trend analysis and a Geographically Weighted Regression (GWR) model, this study analyzed the response of soil organic matter to climate and socio-economic factors in central Heilongjiang Province during the past 25 years. Second soil survey data of China for 1979-1985, 2005 field sampling data, climate observations and socio-economic data for 1980-2005 were analyzed. First, soil organic matter in 2005 was spatially interpolated using the Co-Kriging method along with auxiliary data sets of soil type and pH. The spatio-temporal variability was then studied by comparison with the 1980s second soil census data. Next, the temporal trends in climate and socio-economic factors over the past 25 years were investigated. Finally, we examined the variation of the response of soil organic matter to climate and socio-economic factors using the GWR model spatially and temporally. The model showed that 53.82% area of the organic matter content remained constant and 29.39% has decreased during the past 25 years. The impact of precipitation on organic matter content is mainly negative, with increasing absolute values of the regression coefficient. The absolute value of regression coefficient of annual average temperature has decreased, and more areas are now under its negative effects. In addition, the areas of positive regression coefficient of annual sunshine hours have northward shifted, with the increasing absolute value of positive coefficient and decreasing absolute value of negative coefficient. The areas of positive regression coefficient of mechanized farming as a socio-economic factor have westward shifted, with the increasing absolute value of negative coefficient and decreasing absolute value of positive coefficient. The area of regions with the positive regression coefficient of irrigation has expanded. The regions with positive regression coefficient of fertilizer use have shrinked. The positive regression coefficient of mulch film consumption has significantly increased. The regression coefficient of pesticide consumption was mainly positive in the west of the study area, while it was negative to the east. Generally, GWR model is capable to investigate the influence of both climatic and socio-economic factors, avoided the insufficiency of other research based on the single perspective of climatic or socio-economic factors. Therefore, we can conclude that GWR model could provide methodological support for global change research and serve as basic reference for cultivated land quality improvement and agricultural decision making.

The harpin protein Hpa1 produced by the rice bacterial blight pathogen promotes plant growth and induces plant resistance to pathogens and insect pests. The region of 10-42 residues (Hpa110-42) in the Hpa1 sequence is critical as the isolated Hpa110-42 fragment is 1.3-7.5-fold more effective than the full length in inducing plant growth and resistance. Here we report that transgenic expression of Hpa110-42 in wheat induces resistance to English grain aphid, a dominant species of wheat aphids. Hpa110-42-induced resistance is effective to inhibit the aphid behavior in plant preference at the initial colonization stage and repress aphid performances in the reproduction, nymph growth, and instar development on transgenic plants. The resistance characters are correlated with enhanced expression of defense-regulatory genes (EIN2, PP2-A, and GSL10) and consistent with induced expression of defense response genes (Hel, PDF1.2, PR-1b, and PR-2b). As a result, aphid infestations are alleviated in transgenic plants. The level of Hpa110-42-induced resistance in regard to repression of aphid infestations is equivalent to the effect of chemical control provided by an insecticide. These results suggested that the defensive role of Hpa110-42 can be integrated into breeding germplasm of the agriculturally significant crop with a great potential of the agricultural application.