苹果抗斑点落叶病突变体的细胞筛选

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。

In vitro Screening of Apple Mutant Resistant to Apple Alternaria Blotch (Alternaria mali Roberts)

The present experiement was intended to select apple mutant resistant to Alternaria blotch of apple in vitro from the calli of suscepetible cultivars Yanfu No.10,New Jonagold, Rails and Starkrimson,using host-specific toxin AM-toxin from Alternaria mali Roberts as selective factor. The experiemental results were enumerated as follows:Ⅰ. AM-toxin was obtained from Richards cultivar filtrates of Alternaria mali Roberts. It could induce brown spots on leaves and wilting of shoots accompanied with electrical conductivity severely increasing on susceptible cultivars. But this phenomenon did not appear on the resistant cultivar Fucui.Ⅱ. AM-toxin inhibited severely the growth and survival of calli from susceptible cultivars. But the inhibition became much less severe on Fucui callus compared with susceptible cultivars. All the results showed that AM-toxin was a host-specific toxin and could be used as selective factor.Ⅲ. Multiple step screening system was used,the experiemental results revealed that the screening as effective to increase the resistance to AM-toxin of the susceptible cultivars, but was not to Fucui.Ⅳ. The resistant lines (calli obtained through selecting) could remain resistance to high strength AM-toxin after aparting from selective factor for two months. Comparison of the resistant lines with the original non-selected lines revealed that in the resistant lines the PAL activity was much higher,the POX isoenzyme was 1～3 bands less,and according to cultivar, the POX activity was much higher or lower. Under AM-toxin stress, the electrical conductivity of non-selected lines was much higher.Ⅴ. After inoculating with the spores of the pathogen,the resistant lines were much less susceptible than the original non-selected lines.How to induce and subculture apple callus ,the superiority and implementation of in vitro screening of mutant resistant to disease were discussed in this thesis also.