DNA probes in detection of spiroplasmas and mycoplasma-like organisms in plants and insects

Abstract

DNA probes were applied to detect spiroplasmas and uncultivable mycoplasma‐like organisms (MLOs) in infected plants and insects. The probes consisted of pMC5, a plasmid carrying the RNA genes of Mycoplasma capricolum and pRA1, a plasmid recovered from Spiroplasma citri. Southern blot hybridization of pMC5 with digested DNAs of periwinkle plants infected with S. citri, or with various MLOs, yielded 2 heavy and several weaker bands. The heavy hybridization bands were shown to represent rRNA genes of the plant chloroplasts, indicating significant nucleotide sequence homology between the mycoplasmal rRNA genes and those of plant chloroplasts. Some of the weaker hybridization bands, not revealed in DNA of healthy plants, appeared to represent rRNA gene sequences of the infectious agent. Use of the spiroplasma plasmid as a probe enabled the detection of S. citri in infected plant material and in hemolymph of infected leafhoppers at a high sensitivity level.

Chromosomal DNA fingerprinting--a new method of species and strain identification applicable to microbial pathogens

“…gallisepticum from virulent field isolates of the avian pathogen and in detecting the F strain in areas where vaccination with the F strain took place (Yogev et al, 1988a). The pMC5 rRNA gene probe was also tested as a means of detecting mycoplasmas in infected plants and insect material (Nur et al, 1986). However, the probe reacted strongly with the rRNA-gene sequences of the plant chloroplasts and its use in detecting mycoplasmas in plants was hampered.…”

An Analysis of the Genomic Variability of the Phytopathogenic Mollicute Spiroplasma kunkelii

“…Based on the similarity of some of these proteins to highly variable mycoplasma adhesins (10,32,44), we anticipated finding similar variability among membrane-located spiroplasma proteins. However, that proteins spiralin (28), P58 (57) and P89 (59) grafting (21,58), or by culturing (6,41,43,58). In the latter case, viral DNA can become progressively integrated into the spiroplasma chromosome (41), accounting for some of the variability observed.…”

Environmental Application of Nucleic Acid Hybridization

“…The plant associated bacteria, Frankia and Rhizobium, can be detected by a similar crushed root nodule assay (22,108). Obligate viral pathogens of plants, and spiroplasma, are not amenable to isolation onto cultivation media and are generally obtained from insect (79,104) or plant extracts (8, 63,85) and are detected using a dot blot assay (71,86).…”