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Herbicidal cyanoacrylates with antimicrotubule mechanism of action
Author(s) -
Tresch Stefan,
Plath Peter,
Grossmann Klaus
Publication year - 2005
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.1093
Subject(s) - phragmoplast , microtubule , spindle apparatus , mitosis , microbiology and biotechnology , tubulin , microtubule polymerization , biology , biophysics , cell plate , biochemistry , cytokinesis , cell division , chemistry , cell
Abstract The herbicidal mode of action of the new synthetic cyanoacrylates ethyl (2 Z )‐3‐amino‐2‐cyano‐4‐ethylhex‐2‐enoate (CA1) and its isopropyl ester derivative CA2 was investigated. For initial characterization, a series of bioassays was used indicating a mode of action similar to that of mitotic disrupter herbicides such as the dinitroaniline pendimethalin. Cytochemical fluorescence studies including monoclonal antibodies against polymerized and depolymerized tubulin and a cellulose‐binding domain of a bacterial cellulase conjugated to a fluorescent dye were applied to elucidate effects on cell division processes including mitosis and microtubule and cell wall formation in maize roots. When seedlings were root treated with 10 µ M of CA1 or CA2, cell division activity in meristematic root tip cells decreased within 4 h. The chromosomes proceeded to a condensed state of prometaphase, but were unable to progress further in the mitotic cycle. The compounds caused a complete loss of microtubular structures, including preprophase, spindle, phragmoplast and cortical microtubules. Concomitantly, in the cytoplasm, an increase in labelling of free tubulin was observed. This suggests that the herbicides disrupt polymerization and microtubule stability, whereas tubulin synthesis or degradation appeared not to be affected. In addition, cellulose labelling in cell walls of root tip cells was not influenced. The effects of CA1 and CA2 were comparable with those caused by pendimethalin. In transgenic Arabidopsis plants expressing a green fluorescent protein‐microtubule‐associated protein4 fusion protein, labelled arrays of cortical microtubules in living epidermal cells of hypocotyls collapsed within 160 min after exposure to 10 µ M CA1 or pendimethalin. Moreover, a dinitroaniline‐resistant biotype of goosegrass ( Eleusine indica (L) Gaertn) with a point mutation in α‐tubulin showed cross‐resistance against CA1 and CA2. The results strongly indicate that the cyanoacrylates are a new chemical class of herbicide which possess the same antimicrotubule mechanism of action as dinitroanilines, probably including interaction with the same binding site in α‐tubulin. Copyright © 2005 Society of Chemical Industry