Evolving Multiple Resistance to EPSPS, GS, ALS, PSI, PPO, and Synthetic Auxin Herbicides in Dominican Republic Parthenium hysterophorus Populations. A Physiological and Biochemical Study

Abstract

Two Parthenium hysterophorus populations resistant (R) and susceptible (S) harvested in banana crop from the Dominican Republic were studied. All S plants died when the herbicides were applied at field dose, except with paraquat. For the R population, the order of plant survival was as follows: glyphosate and paraquat > flazasulfuron > glufosinate > fomesafen > 2,4-D. The resistance factors obtained in the dose–response assays showed a high resistance to glyphosate, flazasulfuron, and fomesafen, medium resistance to glufosinate and 2,4-D, and a natural tolerance to paraquat (resistance factor (RF) = 1.0). The I50 values obtained in the 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS), acetolactate synthase (ALS), and glutamine synthetase (GS) activity studies with glyphosate, flazasulfuron, and glufosinate, respectively, were greater in R than in S. The effect of fomesafen was measured by the Proto IX levels, obtaining five times more Proto IX in the S than in the R population. The resistance to 2,4-D in the R was determined by the lower accumulation of ethylene compared to the S population. The studies with 14C-paraquat conclude that the lower absorption and translocation in both the R and S populations would explain the natural tolerance of P. hysterophorus. This is the first case of multiple resistance to herbicides with different mechanisms of action confirmed in P. hysterophorus.

Resistance to Fomesafen, Imazamox and Glyphosate in Euphorbia heterophylla from Brazil

“…Spraying was carried out in a laboratory chamber equipped with an 8001 flat fan nozzle delivering 200 L ha −1 at a constant pressure of 200 kPa. Twenty-one days after treatment (DAT), plant mortality (LD 50 ) and dry weight (g) per plant (GR 50 ) were evaluated [26]. Data were expressed as percentages relative to the untreated control.…”

“…The extraction and activity of the EPSPS enzyme were carried out following the methodology described by Palma-Bautista et al [26]. Five grams of young leaf tissue from the R and S populations of E. heterophylla were ground with liquid N 2 to a fine powder.…”

“…The first was a population of Amaranthus palmeri detected in 2016 in Arkansas (USA) [33], the second was a population of A. tuberculatus detected in 2017 in Ontario (Canada) [34], and both species were found in glyphosate-resistant cotton and soybeans fields [33]. The third population was Epilobium ciliatum confirmed in 2018 in Lolol (Chile) in an olive orchard [35] and the fourth a Parthenium hystherophorus population confirmed in 2020 in Monte Cristi (Dominican Republic) in a field of banana orchards [26].…”

“…Differences in poor control and resistance factors between S and R populations confirm the high resistance of E. heterophylla to fomesafen (Table 3 and Figure 1). The accumulation of Protoporphyrin IX (Proto IX) due to the application of PPO inhibitor herbicides has been a widely used tool for the determination of resistance in weeds, where susceptible weeds accumulate much more of this metabolite [10,26,42]. Our results show that the accumulation of Proto IX in the S population was 7.18 times greater than in the R population treated with 2000 µM of fomesafen (Table 6 and Figure 4A), which is in agreement with the results obtained by other authors on dicot weeds such as E. ciliatum [42], P. hysterophorus [26] and recently on a population of E. heterophylla [11].…”

“…The accumulation of Protoporphyrin IX (Proto IX) due to the application of PPO inhibitor herbicides has been a widely used tool for the determination of resistance in weeds, where susceptible weeds accumulate much more of this metabolite [10,26,42]. Our results show that the accumulation of Proto IX in the S population was 7.18 times greater than in the R population treated with 2000 µM of fomesafen (Table 6 and Figure 4A), which is in agreement with the results obtained by other authors on dicot weeds such as E. ciliatum [42], P. hysterophorus [26] and recently on a population of E. heterophylla [11]. The use of malathion as an inhibitor of CytP450 would interfere with metabolisation of fomesafen in non-toxic products and therefore increased the accumulation of Proto IX in R plants, helping us to be able to interpret the possible mechanisms involved in resistance to PPO (Table 7 and Figure 4B).…”