DSpace Collection:
http://hdl.handle.net/20.500.12207/5410
2024-01-10T19:07:49ZTribenuron-methyl metabolism and the rare Pro197Phe double mutation together with 2,4-D metabolism and reduced absorption can evolve in papaver rhoeas with multiple and cross herbicide resistance to ALS inhibitors and auxin mimics
http://hdl.handle.net/20.500.12207/6073
Title: Tribenuron-methyl metabolism and the rare Pro197Phe double mutation together with 2,4-D metabolism and reduced absorption can evolve in papaver rhoeas with multiple and cross herbicide resistance to ALS inhibitors and auxin mimics
Authors: Palma-Bautista, Candelario; Portugal, João; Vázquez-Garcia, José G.; Osuna, Maria D.; Torra, Joel; Lozano-Juste, Jorge; Gherekhloo, Javid; De Prado, Rafael
Abstract: Multiple resistance mechanisms to ALS inhibitors and auxin mimics in two Papaver rhoeas populations were investigated in wheat fields from Portugal. Dose-response trials, also with malathion (a cytochrome P450 inhibitor), cross-resistance patterns for ALS inhibitors and auxin mimics, alternative herbicides tests, 2,4-D and tribenuron-methyl absorption, translocation and metabolism experiments, together with ALS activity, gene sequencing and enzyme modelling and ligand docking were carried out. Results revealed two different resistant profiles: one population (R1) multiple resistant to tribenuron-methyl and 2,4-D, the second (R2) only resistant to 2,4-D. In R1, several target-site mutations in Pro197 and enhanced metabolism (cytochrome P450-mediated) were responsible of tribenuron-methyl resistance. For 2,4-D, reduced transport was observed in both populations, while cytochrome P450-mediated metabolism was also present in R1 population. Moreover, this is the first P. rhoeas population with enhanced tribenuron-methyl metabolism. This study reports the first case for P. rhoeas of the amino acid substitution Pro197Phe due to a double nucleotide change. This double mutation could cause reduced enzyme sensitivity to most ALS inhibitors according to protein modelling and ligand docking. In addition, this study reports a P. rhoeas population resistant to 2,4-D, apparently, with reduced transport as the sole resistance mechanism.2022-09-11T00:00:00ZThe Asp376Glu mutation and enhanced metabolism controlling the resistance of ALS-inhibiting herbicides in Ixophorus unisetus (J. Presl) Schltdl. from The Bajio, Mexico
http://hdl.handle.net/20.500.12207/6065
Title: The Asp376Glu mutation and enhanced metabolism controlling the resistance of ALS-inhibiting herbicides in Ixophorus unisetus (J. Presl) Schltdl. from The Bajio, Mexico
Authors: Domínguez-Valenzuela, José; Vázquez-García, José; Castro, Patricia; Palma-Bautista, Candelario; Cruz-Hipolito, Hugo; Rey, Maria-Dolores; De Prado, Rafael; Portugal, João
Abstract: A study was carried out to determine the ALS (acetolactate synthase)-inhibitor herbicide
resistance in the Mexican grass Ixophorus unisetus, a troublesome weed in corn crops in Mexico. First,
the resistance was confirmed in field screening assays. Eight populations that survived nicosulfuron
treatment at a field rate of 40 g ai ha−1 were labeled as putative-resistant. Dose–response trials
demonstrated a high resistance in the eight populations (GR50 from 140.33 to 245.46 g ai ha−1
). The
synergism of malathion plus nicosulfuron demonstrated that the non-target-site resistance (NTSR)
mechanism based on cytochrome P450 (Cyt-P450) was involved in five populations of I. unisetus.
Molecular studies revealed that a single-nucleotide change occurs in the amino acid at position 376
(from GAT to GAG), which codifies from Asp-376 to Glu-376. This is the first time that Asp-376-Glu
has been reported in this species. Assays in vitro and in vivo demonstrated I. unisetus cross-resistance
to flucarbazone, penoxsulam, bispyribac-Na, and imazamox. No multiple resistance was found in
two resistant populations exposed to different herbicides. Our results indicate that the lack of good
control over Mexican grass in corn with ALS inhibitors is due to target-site mutation and NTSR
mechanisms (Cyt-P450-mediated metabolism). A strategy should be established in Mexican fields to
continue controlling this weed, including mechanical control practices and a good combination of the
available pre- and post-emergence herbicides.2023-06-22T00:00:00ZConvergent adaptation of multiple herbicide resistance to auxin mimics and ALS- and EPSPS-Inhibitors in Brassica rapa from North and South America
http://hdl.handle.net/20.500.12207/6064
Title: Convergent adaptation of multiple herbicide resistance to auxin mimics and ALS- and EPSPS-Inhibitors in Brassica rapa from North and South America
Authors: Domínguez-Valenzuela, José; Palma-Bautista, Candelario; Vázquez-Garcia, José; Yanniccari, Marcos; Gigón, Ramón; Alcántara-de la Cruz, Ricardo; De Prado, Rafael; Portugal, João
Abstract: Herbicide-resistant weeds have been identified and recorded on every continent where
croplands are available. Despite the diversity of weed communities, it is of interest how selection has
led to the same consequences in distant regions. Brassica rapa is a widespread naturalized weed that
is found throughout temperate North and South America, and it is a frequent weed among winter
cereal crops in Argentina and in Mexico. Broadleaf weed control is based on glyphosate that is used
prior to sowing and sulfonylureas or mimic auxin herbicides that are used once the weeds have
already emerged. This study was aimed at determining whether a convergent phenotypic adaptation
to multiple herbicides had occurred in B. rapa populations from Mexico and Argentina by comparing
the herbicide sensitivity to inhibitors of the acetolactate synthase (ALS), 5-enolpyruvylshikimate-3-
phosphate (EPSPS), and auxin mimics. Five B. rapa populations were analyzed from seeds collected
in wheat fields in Argentina (Ar1 and Ar2) and barley fields in Mexico (Mx1, Mx2 and MxS). Mx1,
Mx2, and Ar1 populations presented multiple resistance to ALS- and EPSPS-inhibitors and to auxin
mimics (2,4-D, MCPA, and fluroxypyr), while the Ar2 population showed resistance only to ALSinhibitors and glyphosate. Resistance factors ranged from 947 to 4069 for tribenuron-methyl, from
1.5 to 9.4 for 2,4-D, and from 2.7 to 42 for glyphosate. These were consistent with ALS activity,
ethylene production, and shikimate accumulation analyses in response to tribenuron-methyl, 2,4-D,
and glyphosate, respectively. These results fully support the evolution of the multiple- and crossherbicide resistance to glyphosate, ALS-inhibitors, and auxinic herbicides in B. rapa populations from
Mexico and Argentina.2023-05-26T00:00:00ZFilago pyramidata tolerant to ALS-Inhibiting herbicides: A new invasive weed in olive groves of Southern Spain
http://hdl.handle.net/20.500.12207/6063
Title: Filago pyramidata tolerant to ALS-Inhibiting herbicides: A new invasive weed in olive groves of Southern Spain
Authors: Palma-Bautista, Candelario; Vásquez-García, José; Domínguez-Valenzuela, José; Alcántara-de la Cruz, Ricardo; De Prado, Rafael; Portugal, João
Abstract: Weeds that usually grow in non-agricultural areas have become increasingly common invading perennial crops. Species of the genus Filago, in addition to invading Spanish olive groves, have developed certain levels of natural tolerance to the acetolactate synthase (ALS) inhibiting herbicide flazasulfuron. The objective of this study was to determine the level and the mechanism involved in the tolerance to flazasulfuron in Filago pyramidata L., which occurs in olive groves of southern Spain, as well as to identify possible cross- or multiple-tolerances by evaluating alternative herbicides for its control. A population resistant (R) to flazasulfuron and a susceptible (S) one of Conyza canadensis were used as references. The accessions of F. pyramidata presented LD50 values (from 72 to 81 g active ingredient (ai) ha−1) higher than the field dose of flazasulfuron (50 g ai ha−1), being 11–12.5 times more tolerant than the S population of C. canadensis, but less than half the R population (170 g ai ha−1). Enzymatically, F. pyramidata was as sensitive to flazasulfuron (I50 = 17.3 μM) as the S population of C. canadensis. Filago pyramidata plants treated with flazasulfuron, combined with 4-chloro-7-nitro-2,1,3-benzoxadiazole, had a growth reduction of up to 85%, revealing the participation of glutathione-S-transferases in herbicide metabolism. Filago pyramidata presented cross-tolerance to the different chemical groups of ALS inhibitors, except triazolinones (florasulam). Synthetic auxins (2,4-D and fluroxypyr) presented good control, but some individuals survived (low multiple resistance). Cellulose synthesis, 5-enolpyruvylshikimate-3-phosphate, 4-hydroxyphenylpyruvate dioxygenase, protoporphyrinogen oxidase, photosystem I, and photosystem II inhibitor herbicides, applied in PRE or POST-emergence, presented excellent levels of control of F. pyramidata. These results confirmed the natural tolerance of F. pyramidata to flazasulfuron and cross-tolerance to most ALS-inhibiting herbicides. The mechanism involved was enhanced metabolism mediated by glutathione-S-transferases, which also conferred low multiple tolerance to synthetic auxins. Even so, herbicides with other mechanisms of action still offer excellent levels of control of F. pyramidata.2023-04-28T00:00:00Z