Over-expression of the Arabidopsis <Emphasis Type="BoldItalic">NPR1</Emphasis> gene in citrus increases resistance to citrus canker

Citrus canker, caused by the bacterial pathogen Xanthomonas citri subsp. citri (Xcc), is a serious leaf and fruit spotting disease affecting many important citrus cultivars including grapefruit and certain sweet oranges. Currently, efficacious and economical disease control measures for highly susceptible citrus cultivars are lacking. Development of commercial cultivars with greater field resistance to citrus canker is the optimum strategy for effective disease management. In this study, we generated transgenic ‘Duncan’ grapefruit (DG) and ‘Hamlin’ sweet orange (Ham) expressing the Arabidopsis NPR1 gene (AtNPR1), which is a key positive regulator of the long-lasting broad-spectrum resistance known as systemic acquired resistance (SAR). Our results indicate that over-expression of AtNPR1 in citrus increases resistance to citrus canker and that the resistance is related with the expression levels of AtNPR1 in the transgenic plants. The line (DG 42-2) with the highest expression level of AtNPR1 was also the most resistant, which developed significant fewer lesions accompanied by a ten-fold reduction in Xcc population. The lesions developed on DG 42-2 were smaller and darker than those on the control and lacked callus formation. These lesion phenotypes resemble those on canker resistant kumquats and canker susceptible citrus trees treated with SAR-inducing compounds. Therefore, over-expression of AtNPR1 in citrus is a promising approach for development of more resistant cultivars to citrus canker.     

美国种子市场准入制度评析

美国种子市场准入制度呈现"对内宽松,对外适度从紧"的特点。对内,尽量取消种子生产经营的行政许可准入限制,为私人投资能自由进入种子产业创造宽松的环境。对外,尽管无外资持股比例的限制,但通过反垄断调查和美国外国投资审查委员会(CFIUS)调查,将那些可能危及美国种子市场竞争秩序及美国种业安全的并购案挡在国门之外。这种市场准入制度有其一定的优异性,对促进中国种子产业的健康发展有着相当的借鉴意义。     

辽宁省玉米市场行情回顾及展望

对2010年辽宁省玉米市场情况进行了介绍。主要对辽宁全省玉米生产形势与特点、市场价格走势及进出口情况等进行了客观描述和探讨分析,并对玉米市场的后期运行情况进行展望。     

A high-throughput method for isolation of salicylic acid metabolic mutants

Background  

Salicylic acid (SA) is a key defense signal molecule against biotrophic pathogens in plants. Quantification of SA levels in plants is critical for dissecting the SA-mediated immune response. Although HPLC and GC/MS are routinely used to determine SA concentrations, they are expensive and time-consuming. We recently described a rapid method for a bacterial biosensor Acinetobacter sp. ADPWH_lux-based SA quantification, which enables high-throughput analysis. In this study we describe an improved method for fast sample preparation, and present a high-throughput strategy for isolation of SA metabolic mutants.     

分子标记辅助选择改良水稻光温敏核不育系华201S的白叶枯病抗性

 以华201S为受体亲本,以含Xa21和Xa7基因的抗白叶枯病材料华恢20为供体亲本,进行1次杂交、3次回交和3次以上自交,每个世代用基因内标记PTA248对Xa21进行分子检测,用连锁标记STSP3（与Xa7的遗传距离为0.9 cM）对Xa7进行检测。新选育的4个株系YR7009(Xa21)、YR7014(Xa21)、YR7016(Xa7)和YR7023(Xa7/Xa21)在生育期、主要农艺性状、育性转换特性方面都与华201S基本相似。YR7009(Xa21)和YR7014(Xa21)对PXO61、PXO99、ZHE173和GD1358等4个菌株具有良好的抗性,而对FuJ和YN24不具有抗性。YR7016(Xa7)和YR7023(Xa7/Xa21)对6个菌株都表现良好的抗性,尤其是聚合双基因的YR7023(Xa7/Xa21)对6个菌株都表现高抗。表明已经将广谱白叶枯病抗性基因Xa21和Xa7渗入到华201S中,成功地改良了华201S的白叶枯病抗性。     

基于ADAMS的拨指链式扶蔗装置的虚拟试验

针对整秆式甘蔗收割机收割倒伏严重的甘蔗时出现堵塞,收割不畅的情况,设计了拨指链式扶蔗装置,以便对甘蔗进行有效的扶起,达到顺利收割的目的。应用动力学仿真软件ADAMS建立了甘蔗—拨指链式扶蔗装置虚拟样机模型。通过虚拟正交试验和虚拟双因素试验研究了扶蔗器的结构参数和运动参数对扶蔗效果的影响规律,并在此基础上进行了实验室台架试验以验证虚拟试验的结论。结果表明：在虚拟试验中,甘蔗最终扶起倒伏角随着下链轮转速的增加而增加,随着前进速度的增加而减小,呈线性关系。在台架试验中下链轮转速和机车前进速度对甘蔗最终扶起角度的影响数值结果略有差异,但各因素对扶蔗效果的影响趋势是一致的,证明虚拟试验的结论在给定条件下是可用的。     

江淮地区双低油菜"油蔬两用"高产栽培技术初探

以江淮地区推广的皖油18、中油杂10号、中双8号3个优质油菜品种为材料,设计播期和密度试验,研究了品种、播期、密度及其交互效应对优质油菜菜薹、菜籽产量与经济效益的影响.结果表明(1)播期对菜薹产量影响不显著,品种×密度、播期×密度、品种×播期×密度互作效应不显著,品种、密度对菜薹产量有极显著影响.(2)密度对菜籽产量影响不显著,品种×播期、品种×密度、品种×播期×密度互作效应不显著,品种、播期对菜籽产量有极显著影响.(3)综合评价以中油杂10号、8月28日播种、密度1.2x105株/hm2时产值最高,经济效益最好.     

中国对虾血细胞凝集素的性能研究↑（*）

对中国对虾(Penaeuschinensis)的血细胞凝集素部分性能的研究结果表明,中国对虾的血淋巴中存在可凝集多种脊椎动物血细胞的因子—血细胞凝集素,凝集活力的大小同中国对虾的健康状况有密切关系,发病对虾体内的凝集素活力明显下降。该凝集素具有较强的热稳定性,100℃处理20min仍具活性;并且具有广泛的pH作用范围,可在pH3～11产生凝集作用;适当增加盐度(18～36)可以提高该凝集素的凝集活性;其活性还会被EDTA强烈抑制;但对Ca2 、Mg2 、Mn2 等离子和多种糖类不敏感。在中国对虾血细胞的细胞膜上未发现有凝集鸡红细胞的活性物质。     

日光温室集中式最优化控制通风系统

为实现日光温室、智能温室无人管理下的智能通风控温,设计一种基于物联网的日光温室集中式最优化控制通风系统。用户根据不同季节、不同作物通过上位机或者物联网平台设定不同的上下限温度值,系统也可自动采集图像,依据数据库作物生长模型自动控制日光温室温度。该系统可将日光温室内温差控制在±1℃,劳动力投入减少30%,显著降低植物生理病害。结果表明:该系统对各种日光温室、智能温室适应性强,既缩短人工劳动工作时间,又避免了人工控制时温度的骤升骤降。