16S rDNA TRFLP profiles of the bacterial endophytic communities inhabiting young Zea plants based on a culture-independent approach. Shown are fluorescently labelled (6FAM) 799f fragments of bacterial DNA from: (A) shoot tissues and (B) root tissues growing in different soils. Each peak is the fluorescence intensity average of six TRFLP amplifications from three pools of five plants, a semi-quantitative indicator of microbial titre. Mixteco plants grown in sand are the average of four TRFLP amplifications from two pools of 5 plants. 16S rDNA amplicons were generated using primers 799f/1492rh and then were restricted using DdeI. Small fragments and those corresponding to 16S chloroplast rDNA or 18S rDNA were removed from the display. Max550 labelled fragments are not shown.