重要农业害虫烟粉虱(Bemisia tabaci)具刺吸式口器,在取食植物韧皮部汁液的同时将唾液分泌到植物中。前期研究发现,烟粉虱通过分泌唾液效应蛋白BtArmet(Bemisia tabaci arginine rich, mutated in early stage of tumors)靶向烟草体内...重要农业害虫烟粉虱(Bemisia tabaci)具刺吸式口器,在取食植物韧皮部汁液的同时将唾液分泌到植物中。前期研究发现,烟粉虱通过分泌唾液效应蛋白BtArmet(Bemisia tabaci arginine rich, mutated in early stage of tumors)靶向烟草体内的半胱氨酸蛋白酶抑制素蛋白,抑制植物的抗虫性。本研究在前期研究的基础上继续筛选与烟粉虱唾液效应蛋白BtArmet互作的烟草蛋白。通过酵母双杂交和双分子荧光互补(bimolecular fluorescence complementation, BiFC)实验发现,普通烟的转录因子WRKY51可以与BtArmet发生互作。烟粉虱的侵染可以显著诱导烟草中NtWRKY51基因表达上调,但病毒诱导的基因沉默(virus-induced gene silencing, VIGS)方法结合烟粉虱生物学测定实验显示,烟粉虱在沉默NtWRKY51基因烟草上的产卵量显著低于阴性对照(沉默空载的烟草),且沉默NtWRKY51基因烟草中水杨酸和茉莉酸介导的激素信号通路均不受影响。上述结果为进一步探究植物对烟粉虱的抗性及其分子机制奠定了基础。展开更多
Resistance of the melon line TGR-1551 to the aphid Aphis gossypii is based on preventing aphids from ingesting phloem sap. In electrical penetration graphs （EPGs）, this resistance has been characterized with A. goss...Resistance of the melon line TGR-1551 to the aphid Aphis gossypii is based on preventing aphids from ingesting phloem sap. In electrical penetration graphs （EPGs）, this resistance has been characterized with A. gossypii showing unusually long phloem salivation periods （waveform El） mostly followed by pathway activities （waveform C） or if followed by phloem ingestion （waveform E2）, ingestion was not sustained for more than 10 min. Stylectomy with aphids on susceptible and resistant plants was performed during EPG recording while the stylet tips were phloem inserted. This was followed by dissection of the penetrated leaf section, plant tissue fixation, resin embedding, and ultrathin sectioning for transmission electron microscopic observation in order to study the resistance mechanism in the TGR. The most obvious aspect appeared to be the coagulation of phloem proteins inside the stylet canals and the punctured sieve elements. Stylets of 5 aphids per genotype were amputated during sieve element （SE） salivation （El） and SE ingestion （E2）. Cross-sections of stylet bundles in susceptible melon plants showed that the contents of the stylet canals were totally clear and also, no coagulated phloem proteins occurred in their punctured sieve elements. In contrast, electron-dense coagulations were found in both locations in the resistant plants. Due to calcium binding, aphid saliva has been hypothesized to play an essential role in preventing/suppressing such coagulations that cause occlusion of sieves plate and in the food canal of the aphid＇s stylets. Doubts about this role of E 1 salivation are discussed on the basis of our results.展开更多
文摘Resistance of the melon line TGR-1551 to the aphid Aphis gossypii is based on preventing aphids from ingesting phloem sap. In electrical penetration graphs （EPGs）, this resistance has been characterized with A. gossypii showing unusually long phloem salivation periods （waveform El） mostly followed by pathway activities （waveform C） or if followed by phloem ingestion （waveform E2）, ingestion was not sustained for more than 10 min. Stylectomy with aphids on susceptible and resistant plants was performed during EPG recording while the stylet tips were phloem inserted. This was followed by dissection of the penetrated leaf section, plant tissue fixation, resin embedding, and ultrathin sectioning for transmission electron microscopic observation in order to study the resistance mechanism in the TGR. The most obvious aspect appeared to be the coagulation of phloem proteins inside the stylet canals and the punctured sieve elements. Stylets of 5 aphids per genotype were amputated during sieve element （SE） salivation （El） and SE ingestion （E2）. Cross-sections of stylet bundles in susceptible melon plants showed that the contents of the stylet canals were totally clear and also, no coagulated phloem proteins occurred in their punctured sieve elements. In contrast, electron-dense coagulations were found in both locations in the resistant plants. Due to calcium binding, aphid saliva has been hypothesized to play an essential role in preventing/suppressing such coagulations that cause occlusion of sieves plate and in the food canal of the aphid＇s stylets. Doubts about this role of E 1 salivation are discussed on the basis of our results.
