A novel thiazolidinone herbicide
375
10. Appleby, A. P. & Valverde, B. E., Behavior of dinitro-
aniline herbicides in plants. W eed T echnol., 3 (1989) 198È
206.
11. Vistica, D. T., Skehan, P., Scudiero, D., Monks, A.,
Pittman, A. & Boyd, M., Tetrazolium-based assays for cel-
lular viability: a critical examination of selected param-
eters a†ecting formazan production, Cancer Res., 51
(1991) 2515È20.
12. Harwood, J. L. In Herbicides, ed. N. R. Baker and M. P.
Percival. Elsevier Science Publishers BV, 1991, pp. 209È
46.
13. Beautement, K., Clough, J. M., de Fraine, P. J. & Godfrey,
C. R. A., Fungicidal b-methoxyacrylates: from natural
products to novel synthetic agricultural fungicides. Pestic.
Sci., 31 (1991) 499È519.
14. Alberts, A. W., Chen, J., Kuron, G., Hunt, V., Hu†, J.,
Ho†man, C., Rothrock, J., Lopez, M., Joshua, H., Harris,
E., Patchett, A., Monaghan, R., Currie, S., Stapley, E.,
Albers-Schonberg, G., Hensens, O., HirshÐeld, J., Hoog-
steen, K., Leisch, J. & Springer, J., Mevinolin: A highly
potent competitive inhibitor of HMG-CoA reductase and
a cholesterol-lowering agent. Proc. Natl Acad. Sci. (USA),
77 (1980) 3957È61.
15. Schaller, H., Maillot-Vernier, P., Belliard, G. & Benve-
niste, P., Increased sterol biosynthesis in tobacco calli
resistant to a triazole herbicide which inhibits demethyla-
tion of 14a-methyl sterols. Planta, 187 (1992) 315È21.
16. Hughes, J. & Mellows, G., Interaction of pseudomonic
acid A with Escherichia coli B isoleucyl-tRNA synthetase.
Biochem. J., 191 (1980) 209È19.
The isoxaben-resistant Arabidopsis used in this study
had the IxrA mutation and was cross-tolerant to 1.
Thus, isoxaben and 1 probably share at least part of a
binding site. It is interesting to note the parallels with
quinclorac, which also appears to inhibit the biosyn-
thesis of plant cell walls and where, again, selectivity
between species is inferred to be due to di†erences at an
unknown molecular site of action. Quinclorac inhibits
the biosynthesis of both celluloses and hemicelluloses
and apparently acts at a site distinct from isoxaben and
1.28,29
Consistent with the observation that both isoxaben
and 1 never inhibited cellulose biosynthesis by more
than 80È90%, and with the observed tissue- and
species-selective e†ects, there is also molecular evidence
for there being more than one cellulose-synthesising
machinery in plants. There are Arabidopsis mutants
which are unable to synthesis cellulose only in speciÐc
tissues, indicating that there may be di†erent forms of
the enzyme in di†erent parts of the plant and that the
cellulose required for primary and secondary cell walls
may also be di†erentially regulated.30h32 Progress in
the Ðnal identiÐcation of the binding site for 1 will most
probably require
a
combination of molecular
approaches (e.g. map-based cloning of the resistant
mutants) and traditional biochemistry (e.g. identiÐca-
tion of the binding site through synthesis of a suitable
photo-affinity label).
17. Updegra†, D. M., Semimicro determination of cellulose in
biological materials. Analyt. Biochem., 32 (1969) 420È4.
18. Heim, D. R., Skomp, J. R., Tschabold, E. E. & Larrinua,
I. M., Isoxaben inhibits the synthesis of acid-insoluble cell
wall materials in Arabidopsis thaliana. Plant Physiol., 93
(1990) 695È700.
REFERENCES
19. Hogetsu, T., Shibaoka, H.
& Shimokoriyama, M.,
Involvement of cellulose synthesis in actions of gibberellin
and kinetin on cell expression. 2,6-Dichlorobenzonitrile as
a new cellulose-synthesis inhibitor. Plant Cell Physiol., 15
(1974) 389È93.
1. Zeneca patent, Preparation of [(phenyl)heterocyclyl] car-
bamates or thiocarbamates as herbicides, WO 94/13652,
1994.
2. Heim, D. R., Roberts, J. L., Pike, P. D. & Larrinua, I. M.,
Mutation of a locus of Arabidopsis thaliana confers resist-
ance to the herbicide isoxaben. Plant Physiol., 90 (1989)
146È50.
3. LaRossa, R. A. & Schloss, J. V., The sulfonylurea herbi-
cide sulfometuron-methyl is an extremely potent and
selective inhibitor of acetolactate synthase in Salmonella
typhimurium. J. Biol. Chem., 259 (1984) 8753È7.
4. Baillie, A. C., Wright, K., Wright, B. J. & Earnshaw, C. G.,
Inhibitors of pyruvate dehydrogenase as herbicides.
Pestic. Biochem. Physiol., 30 (1988) 103È12.
5. Rossomando, E. F., Maldonado, D. & Crean, E. V., E†ect
of hadacidin on growth and adenylosuccinate synthetase
activity of Dictyostelium discoideum. Antimicrob. Agents
Chemother., 14 (1978) 476È82.
6. Rahier, A. & Benveniste, P., Mass spectral identiÐcation
of phytosterols. In Analysis of Sterols and Other Bio-
logically SigniÐcant Steroids, ed. W. D. Nes and E. J.
Parish. Academic Press, San Diego, 1989, pp. 223È50.
7. Zubay, G., In-vitro synthesis of protein in microbial
systems. Ann. Rev. Genet., 7 (1973) 267È87.
8. Hawkes, T. R., Merrick, M. & Dixon, R., Interaction of
puriÐed NtrC protein with nitrogen regulated promoters
from Klebsiella pneumoniae. Mol. Gen. Genet., 201 (1985)
492È8.
20. Heim, D. R., Bjelk, L. A. & Larrinua, I. M., Isolation and
characterisation of a dichlobenil-resistant mutant of Ara-
bidopsis thaliana. W eed. Sci. Soc. Am., 31 (1991) 76.
21. Delmer, D. P., Cellulose biosynthesis. Annu. Rev. Plant
Physiol., 38 (1987) 259È90.
22. Cutler, S. & Somerville, C., Cellulose synthesis: Cloning in
silico. Curr. Biol., 7 (1997) R108ÈR111.
23. Delmer, D. P. & Amor, Y., Cellulose biosynthesis. Plant
Cell, 7 (1995) 987È1000.
24. Tanaka, Y., Sugoh, M., Ji, W., Iwabuchi, J., Yoshida, H. &
Omura, S., Screening method for cellulose biosynthesis
inhibitors with herbicidal activity. J. Antibiot., 48 (1995)
720È5.
25. Heim, D. R., Roberts, J. L., Pike, P. D. & Larrinua, I. M.,
A second locus, Ixr Arabidopsis thaliana, that confers
resistance to the herbicide isoxaben. Plant Physiol., 92
(1990) 858È61.
26. Heim, D. R., Skomp, J. R., Waldron, C. & Larrinua, I. M.,
Di†erential response to isoxaben of cellulose biosynthesis
by wild-type and resistant strains of Arabidopsis thaliana.
Pestic. Biochem. Physiol., 39 (1991) 93È9.
27. Delmer, D. P., Read, S. M. & Cooper, G., IdentiÐcation of
a receptor protein in cotton Ðbres for the herbicide 2,6-
dichlorobenzonitrile. Plant Physiol., 84 (1987) 415È20.
28. Koo, S. J., Neal, J. C. & DiTomaso, J. M., 3,7-Dichloro-
quinolinecarboxylic acid inhibits cell-wall biosynthesis in
maize roots. Plant Physiol., 112 (1996) 1383È9.
9. Zeneca patent, Assays for aminoacyl tRNA synthetases
and their inhibitors and their use in the identiÐcation of
herbicides, WO 95/09927, 1995.