Whole-Plant and Seed Bioassays for Resistance Confirmation

Burgos, Nilda R.

doi:10.1614/ws-d-14-00019.1

Cited by 67 publications

(75 citation statements)

References 50 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…A dose-response experiment not only determines the discriminating dose for large-scale resistance testing as mentioned in the previous section, but also evaluates the highest dose that a population can tolerate and to obtain clues for the potential resistance mechanism(s). High resistance level may not only indicate targeted genetic point mutation, but also could be indicative of nontarget site resistance mechanism (Burgos et al, 2015). The R/S ratios of LD xx or GR xx values are used to compare the magnitude of resistance of different populations (Burgos et al, 2013).…”

Section: Discussionmentioning

confidence: 99%

First evidence of multiple resistance of Sumatran Fleabane (Conyza sumatrensis (Retz.) E.Walker) to five- mode-of-action herbicides

et al. 2019

View full text Add to dashboard Cite

Herbicide resistance is the evolutionary response of weeds to the selection pressure caused by repeated application of the same active ingredient. It can result from two different mechanisms, known as target site resistance (TSR) and non-target site resistance (NTSR). In addition to single-herbicide resistance, multiple resistance can occur due to herbicides selection or accumulation of resistance genes by cross-pollination. The aim of this research was to investigate the suspect of multiple herbicide resistance of Sumatran Fleabane (Conyza sumatrensis (Retz.) E.Walker) to herbicides frequently used as a burndown application. Dose-responses in a whole-plant assay were carried out to investigate multiple-resistance of Sumatran fleabane to paraquat, saflufenacil, diuron, 2,4-D and glyphosate. Results indicated that the resistance index (ratio R/S) based on herbicide rate to cause 50% mortality (LD 50 ) were 25.51, 1.39, 7.29, 1.84 and 7.55 for paraquat, saflufenacil, diuron, 2,4-D and glyphosate, respectively. Based on herbicide rate required to cause a 50% reduction in plant growth (GR 50 ), the resistant index were 51.83, 14.10, 5.05, 3.96 and 32.90 for the same herbicides, respectively. Our results confirmed multiple resistance of Conyza sumatrensis from Paraná-Brazil to herbicides from five-mode of-action. This was the first report of Conyza sumatrensis resistant to 2,4-D and the first case of Conyza sumatrensis presenting multiple resistant to herbicides from fivemode of-action in the world.

show abstract

Section: Discussionmentioning

confidence: 99%

First evidence of multiple resistance of Sumatran Fleabane (Conyza sumatrensis (Retz.) E.Walker) to five- mode-of-action herbicides

et al. 2019

View full text Add to dashboard Cite

show abstract

“…This is the reason for the application recommendation of OnDuty™ WG herbicide in commercial IMI-rice fields, where it must be applied as pre-emergence or early post-emergence to the plants (preferably 0-5-day after sowing, and not exceed 7-day after sowing or 1-2-leaf stage). Seed bioassay was conducted to evaluate the pre-emergence activity of the IMI-herbicides premix to weedy rice populations and rice varieties, while whole-plant dose response experiment allowed us to confirm resistance of the populations with post-emergence activity [33]. Hence, both experiments aimed to evaluate the occurrence and level of resistance of weedy rice populations and rice varieties to imazapic and imazapyr that best applied as pre- and early post-emergence herbicides, respectively.…”

Section: Discussionmentioning

confidence: 99%

Ser-653-Asn substitution in the acetohydroxyacid synthase gene confers resistance in weedy rice to imidazolinone herbicides imazapic and imazapyr in Malaysia

Ruzmi

Ahmad-Hamdani

Mazlan

2019

Preprint

View full text Add to dashboard Cite

The IMI-herbicides rice package has been recognized by all means among the most efficient chemical approaches for weedy rice control nowadays. Inevitably, the continuous and sole dependence, as well as ignorance on the appropriate use of imidazolinone herbicides in the IMI-herbicides rice package by rice growers has caused the development of herbicide resistance in weedy rice populations across many IMI-herbicides rice package adopted countries, inclusive of Malaysia. Hence, a comprehensive study was conducted to elucidate the occurrence, level, and mechanisms endowing resistance to IMI-herbicides on field-reported resistant (R) weedy rice populations collected from IMI-rice fields in Kampung Simpang Sanglang, Perlis (A), Kampung Behor Mentalon, Perlis (B), and Kampung Sungai Kering, Kedah (C). The collected weedy rice populations were compared with a susceptible weedy rice population (S), an imidazolinone-resistant rice cultivar (IMI-rice), and a susceptible local rice cultivar (MR219). Dose-response experiments were carried out using commercial IMI-herbicides (premix of imazapic and imazapyr) available in the IMI-herbicides rice package, in the seed bioassay and whole-plant dose-response. Based on the Resistance Index (RI) quantification in both experiments, the cross-resistance pattern of weedy rice populations and rice varieties to imazapic and imazapyr was determined. Molecular investigation was carried out by comparing acetohydroxyacid synthase (AHAS) gene sequences between resistant (R) weedy rice populations (A, B, and C), S population, IMI-rice, and MR219. Evidently, the AHAS gene sequences of R weedy rice were identical to the IMI-rice, revealing that amino acid substitution of Ser-653-Asn occurs in both R populations and IMI-rice, but neither in MR219 nor S plants. In vitro assays were conducted using analytical grade imidazolinone herbicides of imazapic (99.3%) and imazapyr (99.6%) with seven concentrations. The results demonstrated that the AHAS enzyme extracted from R populations and IMI-rice were less sensitive to IMI-herbicides in comparison to S and MR219, further supporting the IMI-herbicides resistance was conferred by target site mutation. In conclusion, the basis of imidazolinone resistance in selected populations of Malaysia weedy rice was due to a Ser-653-Asn mutation that reduced sensitivity of the target site to IMI-herbicides. The current study presents the first report of resistance mechanism in weedy rice in Malaysian rice fields.

show abstract

“…For each population, the control treatment (without herbicide solution) with 5 mL distilled water was also considered. Then, the Petri dishes were placed in an incubator at 25 • C. After seven days, the shoot lengths of the coleoptiles in all of the seedlings were measured and expressed as the percentage of the shoot length of coleoptile compared to the control [13].…”

Section: Seed Bioassaymentioning

confidence: 99%

“…Each replicate pot contained five plants. Four weeks after sowing, at the three-to-four-leaf stage (as BBCH scale in [13][14], herbicides were applied at different rates using a calibrated sprayer with a flat-fan nozzle (TeeJet 8001) to deliver 250 L ha −1 of spray solution at 200 kPa. One untreated control (without herbicide application) for each population has been used.…”

Section: Whole Plant Dose-response Assaymentioning

confidence: 99%

The First Case of Short-Spiked Canarygrass (Phalaris brachystachys) with Cross-Resistance to ACCase-Inhibiting Herbicides in Iran

et al. 2019

View full text Add to dashboard Cite

The weed Phalaris brachystachys Link. severely affects winter cereal production. Acetyle-CoA Carboxylase (ACCase)-inhibiting herbicides are commonly used to control this weed in wheat fields. Thirty-six populations with suspected resistance to ACCase-inhibiting herbicides were collected from wheat fields in the Golestan Province in Iran. A rapid test performed in Petri dishes and whole-plant dose-response experiments were conducted to confirm and investigate the resistance level of P. brachystachys to ACCase-inhibiting herbicides. The seed bioassay results showed that 0.02 mg ai L −1 clodinafop-propargyl (CP) and 1.36 mg ai L −1 of the diclofop-methyl (DM) solution were the optimal amounts for reliably screening resistant and susceptible P. brachystachys populations. In the whole plant bioassay, all populations were found to be resistant to CP, resistance ratios ranging from 2.7 to 11.6, and all of the CP-resistant populations exhibited resistance to DM. Fourteen populations showed low resistance to cycloxydim, and thirteen of these populations were also 2-fold resistant to pinoxaden. The results showed that DM resistance in some P. brachystachys populations is likely due to their enhanced herbicide metabolism, which involves Cytochrome P450 monooxygenases, as demonstrated by the indirect assay. This is the first report confirming the cross-resistance of ACCase-inhibiting herbicides in P. brachystachys in Iran.

show abstract

Whole-Plant and Seed Bioassays for Resistance Confirmation

Cited by 67 publications

References 50 publications

First evidence of multiple resistance of Sumatran Fleabane (Conyza sumatrensis (Retz.) E.Walker) to five- mode-of-action herbicides

First evidence of multiple resistance of Sumatran Fleabane (Conyza sumatrensis (Retz.) E.Walker) to five- mode-of-action herbicides

Ser-653-Asn substitution in the acetohydroxyacid synthase gene confers resistance in weedy rice to imidazolinone herbicides imazapic and imazapyr in Malaysia

The First Case of Short-Spiked Canarygrass (Phalaris brachystachys) with Cross-Resistance to ACCase-Inhibiting Herbicides in Iran

Contact Info

Product

Resources

About