用共聚焦激光扫描显微镜观测GFP标记的内生固氮菌Klebsiella oxytoca SA2侵染水稻根  

Using Confocal Laser Scanning Microscope to Visualize the Infection of Rice Roots by GFP-labelled Klebsiella oxytoca SA2, an Endophytic Diazotroph

作　　者：安千里[1] 杨学健[1] 董越梅[1] 冯丽洁[1] 匡柏健[1] 李久蒂[1] 

机构地区：[1]中国科学院植物研究所,北京100093

出　　处：《Acta Botanica Sinica》2001年第6期558-564,共7页Acta Botanica Sinica（植物学报：英文版）

基　　金：国家自然科学基金 ( 3 95 70 0 65 ) ;国家高技术发展计划"863"项目 ( 10 1_0 3_0 4_2 )&&

摘　　要：用高效绿色荧光蛋白 (greenfluorescentprotein ,GFP)突变体EGFPmut2的基因标记内生固氮菌———产酸克雷伯氏菌 (Klebsiellaoxytoca (Fl櫣ｇｇｅ)Lautrop)SA2 ,用标记菌接种限菌培养条件下生长的水稻 (OryzasativaL .)幼苗 ,在接种后 1、2、4、8、12、16和 2 1d ,用共聚焦激光扫描显微镜对水稻鲜根进行光学切片 ,显示了标记菌从水稻根成熟区表面向根内入侵的过程。定殖在根表面的标记菌主要从侧根伸出的位置侵入侧根皮层 ,从邻近发生侧根的位置进入内皮层和维管柱。SA2还能从初生根成熟区无侧根伸出的位置侵入皮层向维管柱迁移。SA2入侵水稻根引发了水稻根局部的过敏反应以阻滞细菌进一步入侵 ,表现为侵入根内的细菌周围的根细胞细胞壁变厚 ,在蓝光下发出很强的黄绿荧光。The infection of rice (Oryza sativa L.) roots by a GFP-labelled endophytic nitrogen-fixing bacterium, Klebsiella oxytoca SA2, was visualized in a living state with a confocal. laser scanning microscope. Rice seedlings were gnotobiotically grown in tubes with agar medium and roots were optically sectioned after inoculation of 1, 2, 4, 8, 12, 16 and 21 d. Microscopic observation showed significantly the process that the bacteria infected the roots from the root surface to the vascular tissues in the root maturation zone. After colonization on the root surface, the GFP-labelled bacteria penetrated preferentially into the cortex of the developed lateral roots and colonized inter- and intracellularly in the lateral root. Afterwards, they moved into the vascular cylinder at sites where the endodermis was modified by the outgrowth and the development of the lateral loot. In addition, they also could penetrate into the cortex with less frequency and efficiency of the primary roots at sites where no lateral root was emerged. Cell walls of the root cells close to the invading bacteria were thickened and strong yellow-green fluorescence of them was visualized under blue light. The phenomena may represent a localized hypersensitive reaction of root cells to further restrict bacterial invasion.

关 键 词：内生固氨菌 侵染 绿色荧光蛋白 共聚焦激光扫描显微镜 水稻根 植物 

分 类 号：Q939[生物学—微生物学]