Sieve element specific labeling with an anti-idiotypic monoclonal antibody mimic of the phytotoxin dothistromin

Abstract

A monoclonal antibody, 12C9, an anti-idiotypic mimic of dothistromin, a toxin produced by Dothistroma pini, was found to label the cell wall of sieve elements in a number of different plant tissues and species. The antibody labeled apple leaf tissue, tobacco leaf mid vein, leaf and meristem, and Coprosma robusta leaf mid vein. Labeling was restricted to cell walls of sieve elements and did not label the companion cells or the lumen of the cells. The antibody labeled over a wide range of dilutions. This antibody could be used to differentiate sieve elements from other types of phloem. It could also be used to co-localize sieve elements and microorganisms such as phytoplasmas stained with DAPI.