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Ingo Hein Paul R. J. Birch Sarah Danan Véronique Lefebvre Damaris Achieng Odeny Christiane Gebhardt Friederike Trognitz Glenn J. Bryan 《Potato Research》2009,52(3):215-227
Cultivated potato is susceptible to many pests and pathogens, none of which is more of a threat to potato agriculture than
the late blight disease, caused by the oomycete Phytophthora infestans (Mont.) de Bary. To date all efforts to thwart this most adaptive of pathogens have failed, and early attempts to deploy
‘R genes’ introgressed from the wild Mexican hexaploid Solanum demissum ended in abject failure. With the advent of facile gene mapping and cloning, allied to knowledge of plant resistance gene
structure, renewed efforts are leading to mapping and isolation of new sources of late blight resistance in potato wild species,
many of which are being performed under the auspices of the BIOEXPLOIT project (Sub-project 2). We document recent advances
in late blight resistance gene mapping and isolation, and postulate how these genes, allied to knowledge of pathogen effectors
and their recognition specificity, may greatly enhance our chances of halting the progress of late blight disease in potato
crops worldwide. 相似文献
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Pea endocarp tissue generates a total nonhost resistance response against inappropriate pathogens such as the bean pathogen, Fusarium solani f. sp. phaseoli (Fsph) within 6 h. An array of plant components induced include: Pisatin (a phytoalexin), defensins, PR genes and hydrolytic enzymes in the non-host resistance response. This nonhost resistance response is similar but swifter than the responses induced by the compatible true pathogen, F. solani f. sp. pisi (Fspi). It was previously noted that a DNase released by both fungi is involved in induction of these resistance responses within pea endocarp tissue. This report demonstrates the cytological damage that occurs within nuclear DNA of both compatible and incompatible fungi when in contact with pea endocarp tissue and in the presence of DNase activity. The severity of damage to the bean pathogen exceeds that of the pea pathogen and requires only 2 h of contact with the pea tissue to develop. This accumulation of DNA damage is proposed to be the ultimate termination factor in this and other non-host resistance reactions. An updated DNase signaling scheme of the nonhost resistance of pea is presented. 相似文献
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利用红原若尔盖地区1980—2010年气象资料,根据牧草发育期各阶段的适应气象条件要求,对若尔盖草原牧草生长气象条件的适应性进行分析,并通过灰度关联法作出牧草生长高度预报方程,得出如下结论:(1)红原若尔盖地区31年中年平均温度为1.4℃,31年中年平均降水量为643.3 mm,年平均日照时数为2479.3 h,年降水量和日照时数呈下降趋势。(2)早熟禾返青时所需要的温度为0℃以上,当到夏季末时,温度下降到10℃以内时,便开始黄枯,牧草开始发育时所需要的降水均为10 mm左右,当降水量达到45 mm左右时,牧草进入枯黄阶段,对于日照时数而言,牧草发育时返青期所需日照为70 h左右,当日照达到80 h左右时,牧草开始黄枯。(3)灰度关联法对早熟禾牧草生长高度的预报效果很好,此方法所做出来的牧草生长高度的预报方程可以通过显著性检验。 相似文献
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Mel频率倒谱系数MFCC在说话人识别中已被广泛使用。本文以MFCC为声音信号的特征参数提取的标准。识别部分采用自组织神经网络的方法进行建模,实验结果表明该方法有较高的识别率。 相似文献
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植物天然免疫性研究进展及其对作物抗病育种的可能影响 总被引:3,自引:0,他引:3
植物定植在充满各种病原菌的环境中却能健康生长,显示其拥有一套免疫系统以应对病原物的侵染。最近,人们发现植物免疫系统至少包括2个层次:第一层为病原相关分子模式(PAMP)激发的免疫性(PTI),即植物通过细胞表面模式识别受体(PRRs)对病原菌的PAMPs进行分子识别,从而启动植物的防卫反应;第二层为病原菌效应子激发的免疫性(ETI),即有些毒性强的病原菌通过产生效应子(effectors)来抑制PTI,从而突破植物的第一道防线,而植物又进化出新的分子受体(例如R基因编码的NBS-LRR蛋白质)以侦察病原菌效应子并启动第二道防卫反应。数亿年来,病原菌的侵染和植物的防卫交替进行,促进了病原菌和植物基因组的共进化。最新的研究还发现,黄单胞杆菌TAL effectors和寄主植物DNA 的相互识别中,利用了精准的分子密码。TAL effector类蛋白识别植物靶基因的启动子序列,识别模式是2个氨基酸识别一个核苷酸。通过这种识别,TAL effector操控植物靶基因的表达,引起寄主植物的感病或抗病反应。上述抗病分子机理研究的突破,将对植物抗病育种产生重要影响。 相似文献