Abstract

Colloidal gold is a very extensively used label for light and electrón microscopy and its advantages opposite fluorochromes are well known. However. it is difficult to resolve by optical microscopy without silver enhancement procedures. The techniques described herein provide for the detection of immunogold labeled plant viruses using láser scanning confocal microscopy in reflected signal detection mode. Antibody-conjugated colloidal gold partióles observed by reflected laser light signals were localized in either tissue of lettuce infectious yellows (LIYV) and maize stripe viruses-infected plant samples or LIY V-infected protoplasts and coincided with immune labeled areas observed by transmission and scanning electrón microscopy- The technique permits visualization of gold labeling avoiding silver enhancement on semithin sections and resin blocks; however, in some cases, other reflected light signáis can interfere. This technique could be useful as a complement to, or alternate for immune-electron microscopic studies