The arbuscular mycorrhizal （AM） symbiosis is a widespread mutualistic association between soil fungi （Glomeromycota） and the roots of most plant species. AM fungi are obligate biotrophs whose development is partia...The arbuscular mycorrhizal （AM） symbiosis is a widespread mutualistic association between soil fungi （Glomeromycota） and the roots of most plant species. AM fungi are obligate biotrophs whose development is partially under the control of their plant host. We explored the possibility to combine metabolomic and transcriptomic approaches to find putative mycorrhiza-associated metabolites regulating AM fungal development. Methanol extracts of Medicago truncatula roots colonized or not with the AM fungus Rhizophagus irregularis were analyzed and compared by ultra- high-performance liquid chromatography （UHPLC）, high-resolution mass spectrometry （Q-TOF）, and multivariate statisti- cal discrimination. We detected 71 mycorrhiza-associated analytes exclusively present or at least 10-fold more abundant in mycorrhizal roots. To identify among these analytes those that could regulate AM fungal development, we fraction- ated by preparative and semi-preparative HPLC the mycorrhizal and non-mycorrhizal root extracts and established how the 71 analytes were distributed among the fractions. Then we tested the activity of the fractions on germinating spores of R. irregularis by quantifying the expression of 96 genes known for their diverse in planta expression patterns. These investigations reveal that propionyl- and butyryl-carnitines accumulated in mycorrhizal roots. The results suggest that these two molecules regulate fungal gene expression in planta and represent interesting candidates for further biologi- cal characterization.展开更多
Color image printing technique on ink jetting printer is introduced.Color shading method such as dithering,Amplitude Modulation(AM)screening and Frequency Modulation(FM)screening is presented.Some solutions to the pro...Color image printing technique on ink jetting printer is introduced.Color shading method such as dithering,Amplitude Modulation(AM)screening and Frequency Modulation(FM)screening is presented.Some solutions to the problems with FM screening are given. An application program under Windows is developed.展开更多
从苹果斑点落叶病菌(Alternaria mali Roberts)的Richards培养液中提取的AM—毒素,在254nm处有吸收峰。经叶片法、插枝法、电导率法等生物测试表明,AM—毒素具有寄主专化性。以AM—毒素为选择因子,配制成选择培养基,以感病品种岩富10、...从苹果斑点落叶病菌(Alternaria mali Roberts)的Richards培养液中提取的AM—毒素,在254nm处有吸收峰。经叶片法、插枝法、电导率法等生物测试表明,AM—毒素具有寄主专化性。以AM—毒素为选择因子,配制成选择培养基,以感病品种岩富10、新乔纳金、国光、新红星的愈伤组织为材料,采用多步选择系统筛选抗病突变体。所得到的抗病系离开选择因子2个月后,仍保持获得的抗病性。与未经选择的原始型相比,抗病系的苯丙氨酸解氨酶活性增强,过氧化物酶同工酶带减少1～3条。在AM—毒素作用下,抗病系电导率增加速度显著小于原始型。接种病原菌孢子后,抗病系较原始型抗病。展开更多
文摘The arbuscular mycorrhizal （AM） symbiosis is a widespread mutualistic association between soil fungi （Glomeromycota） and the roots of most plant species. AM fungi are obligate biotrophs whose development is partially under the control of their plant host. We explored the possibility to combine metabolomic and transcriptomic approaches to find putative mycorrhiza-associated metabolites regulating AM fungal development. Methanol extracts of Medicago truncatula roots colonized or not with the AM fungus Rhizophagus irregularis were analyzed and compared by ultra- high-performance liquid chromatography （UHPLC）, high-resolution mass spectrometry （Q-TOF）, and multivariate statisti- cal discrimination. We detected 71 mycorrhiza-associated analytes exclusively present or at least 10-fold more abundant in mycorrhizal roots. To identify among these analytes those that could regulate AM fungal development, we fraction- ated by preparative and semi-preparative HPLC the mycorrhizal and non-mycorrhizal root extracts and established how the 71 analytes were distributed among the fractions. Then we tested the activity of the fractions on germinating spores of R. irregularis by quantifying the expression of 96 genes known for their diverse in planta expression patterns. These investigations reveal that propionyl- and butyryl-carnitines accumulated in mycorrhizal roots. The results suggest that these two molecules regulate fungal gene expression in planta and represent interesting candidates for further biologi- cal characterization.
文摘Color image printing technique on ink jetting printer is introduced.Color shading method such as dithering,Amplitude Modulation(AM)screening and Frequency Modulation(FM)screening is presented.Some solutions to the problems with FM screening are given. An application program under Windows is developed.
文摘从苹果斑点落叶病菌(Alternaria mali Roberts)的Richards培养液中提取的AM—毒素,在254nm处有吸收峰。经叶片法、插枝法、电导率法等生物测试表明,AM—毒素具有寄主专化性。以AM—毒素为选择因子,配制成选择培养基,以感病品种岩富10、新乔纳金、国光、新红星的愈伤组织为材料,采用多步选择系统筛选抗病突变体。所得到的抗病系离开选择因子2个月后,仍保持获得的抗病性。与未经选择的原始型相比,抗病系的苯丙氨酸解氨酶活性增强,过氧化物酶同工酶带减少1～3条。在AM—毒素作用下,抗病系电导率增加速度显著小于原始型。接种病原菌孢子后,抗病系较原始型抗病。
