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QUIK STATS (last updated Dec 29, 2013 )
CONTRIBUTING WEED SCIENTISTS
Goal. Investigate the possibility to use 1,8-naphthalic anhydride metabolism inductor to control acetolactate synthase (ALS) inhibitor-resistant biotype of common graminicides of aryloxyphenoxypropionic acid class in rice. Methodology. The interaction of 1,8-naphthalic anhydride and fenoxaprop-p-ethyl on variety Vikont rice plants was studied under laboratory aseptic conditions. The data were statistically processed. Results. In Ukraine we have identified the biotype of resistant to herbicide - ALS inhibitors Echinochloa crus-galli, which is cross-resistant to widely used herbicides - ALS inhibitors of the following chemical classes: imidazolinones (imazamox, imazapyr), sulfonylurea (nicosulfuron), triazolopyrimidines (penoxsulam). The possibilities of chemical control of weeds in rice, corn, sunflower, etc. crops are significantly limited. Multi-resistance of this weed biotype to herbicides - inhibitors of photosynthesis, mitotic cycle, 5-enolpyruvylshikimate-3-phosphate synthase, acetyl-CoA-carboxylase, protein synthesis - has not been detected. Therefore, the use of graminicides of aryloxyphenoxypropionate class is promising for the control of this ALS-resistant biotype of Echinochloa crus-galli. To increase the selectivity of fenoxaprop-P-ethyl application to rice plants, we propose to treat the seeds of the crop with the inductor of xenobiotics metabolism in plants - 1.8-naphthalic anhydride before sowing. When using 1.8-naphthalic anhydride in concentrations of 10-5 M, phytotoxicity of fenoxaprop-P-ethyl in concentrations of 10-6 and 10-5 M to rice plants is effectively reduced. Conclusions. The use of 1.8-naphthalic anhydride is promising for increasing the selectivity of fenoxaprop-P-ethyl for rice plants and allows the development of technologies using graminicides of aryloxyphenoxypropionate class to control ALS-resistant biotype of Echinochloa crus-galli in crops. Also, it is necessary to pay attention to the problem of ALS-resistant weed biotype proliferation control in agrophytocenoses in regions of Ukraine.
Barnyardgrass (Echinochloa crus-galli) is one of the top 15 herbicide-resistant weeds around the world that interferes with rice growth, resulting in major losses of rice yield. Thus, multi-herbicide resistance in barnyardgrass presents a major threat, with the underlying mechanisms that contribute to resistance requiring elucidation. In an attempt to characterize this multi-herbicide resistance at the proteomic level, comparative analysis of resistant and susceptible barnyardgrasses was performed using iTRAQ, both with and without quinclorac, bispyribac-sodium and penoxsulam herbicidal treatment. A total of 1342 protein species were identified from 2248 unique peptides by searching the UniProt database and conducting data analysis. Approximately 904 protein species with 4774 Gene Ontology (GO) terms were grouped into the categories of biological process, cellular component and molecular function. Among these, 688 protein species were annotated into 1583 KEGG pathways, with 980 protein species relating to metabolism and 93 relating to environmental information processing. A total of 292 protein species showed more than a 1.2-fold change in abundance in the resistant biotype relative to the susceptible biotype. Furthermore, herbicide treatment resulted in 157 protein species that showed more than a 1.2-fold change in the resistant biotype. Moreover, physiological analyses demonstrated an ecological fitness cost in the resistant biotype.
Significance: While some studies have shown a fitness cost to be associated with an altered ecological interaction, our understanding of the fitness costs associated with herbicide resistance are limited. Herein, physiological and proteomic analysis demonstrates herbicide resistance associated ecological fitness cost and potential mechanisms of herbicide-resistance in resistant biotypes of E. crus-galli. The results presented herein have revealed differences in ecological adaptation between resistant and susceptible biotypes in E. crus-galli and provide a fundamental basis enabling the development of new strategies for weed control. Lastly, this is the first large scale proteomics study to examine herbicide stress responses in different barnyardgrass biotypes.