Common and distinct gene expression patterns induced by the herbicides 2,4‐dichlorophenoxyacetic acid, cinidon‐ethyl and tribenuron‐methyl in wheat

Abstract

In wheat, herbicides are used to control weeds. Little is known about the changes induced in the metabolism of tolerant plants after herbicide treatment. The impact of three herbicides [2,4-dichlorophenoxyacetic acid (2,4-D), cinidon-ethyl and tribenuron-methyl] on the wheat transcriptome was studied using cDNA microarrays. Gene expression of plants grown in a controlled environment or in the field was studied between 24 h and 2 weeks after treatment. Under controlled conditions, 2,4-D induced genes of the phenylpropanoid pathway soon after treatment. Cinidon-ethyl triggered peroxidase and defence-related gene expression under controlled conditions, probably because reactive oxygen species are released by photo-oxidation of protoporphyrin-IX. The same genes were upregulated in the field as under controlled conditions, albeit at a weaker level. These results show that cinidon-ethyl specifically induces genes involved in plant defence. Under controlled conditions, tribenuron-methyl did not change the expression profile immediately after treatment, but defence-related genes were upregulated after 1 week. Sulfonylurea compounds such as tribenuron-methyl specifically inhibit acetolactate synthase and are rapidly detoxified, but the activity of some of the resulting metabolites could explain later changes in gene expression. Finally, overexpression of the isopropylmalate synthase gene, involved in branched-chain amino acid synthesis, and of defence-related genes was observed in the field after sulfonylurea treatment.

Expression Patterns of Genes Involved in the Defense and Stress Response of Spiroplasma citri Infected Madagascar Periwinkle Catharanthus roseus

“…Otherwise, expression of certain genes would be affected by biotic and abiotic stresses, and other environmental factors. Lower expression in naturally infected, compared to experimentally infected, plants support the result of other related research that showed the same genes in herbicide treated wheat, as under controlled conditions, were up-regulated in the field at a weaker level [59]. …”

Overexpression of a specific soybean GmGSTU4 isoenzyme improves diphenyl ether and chloroacetanilide herbicide tolerance of transgenic tobacco plants

“…However, indirect tolerance by the effective scavenging of the byproducts of oxidative stress caused by the inhibitory activity of the herbicides is also important, as demonstrated by the increased tolerance to oxyfluorfen, which is not detoxified by glutathione conjugation. As shown by microarray analysis in wheat treated with cinidon-ethyl, a herbicide that also inhibits protoporphyrinogen oxidase, the primary response of wheat was the upregulation of genes coding for antioxidant enzymes, thus indicating the importance of counteracting oxidative stress caused by these peroxidizing herbicides (Pasquer et al, 2006). The dual GST/GPOX function of many GSTs might contribute to peroxidizing herbicides tolerance in soybean (Skipsey et al, 1997) and in weed species , and is of great importance in alleviating abiotic stresses mediated oxidative stress (Kilili et al, 2004;Roxas et al, 1997).…”

Detoxification without Intoxication: Herbicide Safeners Activate Plant Defense Gene Expression

“…Additionally, temporal patterns of gene expression (as reported with different herbicides by Pasquer et al, 2006) in response to safeners or RES oxylipins would be extremely informative from the standpoint of understanding the time course of plant responses to a potent inducer of xenobiotic detoxification, in comparison with endogenous RES oxylipin signaling molecules. From a molecular standpoint, it would be of great interest to determine if regulation of OPR gene expression in response to various stresses occurs at the transcriptional, posttranscriptional, or posttranslational level.…”