Tolerance of Common Bean Plants to Ethoxysulfuron Herbicide and the Mechanism Involved in the Process

Abstract

-The objectives of this study were to determine the effect of herbicide ethoxysulfuron on the development of commom bean (Phaseolus vulgaris), to evaluate the impact of the herbicide on the crop grain yield and to determine the mechanism of tolerance of common bean to ethoxysulfuron. Field experiments were carried out with several doses of ethoxysulfuron to determine its effect on the grain yield of two varieties of common bean ("IPR Andorinha", "IPR Tangará"). The mechanism of plant tolerance was evaluated through several methods, including the analysis of the ALS enzyme sensitivity to herbicide and the use of P450 inhibitors (the insecticides malathion + chlorpyrifos) and the use of antidote (mefenpyr-diethyl). When the rate of ethoxysulfuron was 83.2 g ha -1 , the grain yield loss reached 25% (IPR Tangará) and 35% (IPR Andorinha). The ALS enzyme activity was severely reduced even at low concentrations ethoxysulfuron (1 μM), indicating that the mechanism of tolerance is not the insensitivity of the herbicide target enzyme. The inhibitors of herbicide detoxification increased the sensitivity of the bean plants to ethoxysulfuron, and the antidote (stimulator of herbicide degradation) mitigated the herbicidal effect. These results strongly support the hypothesis that the mechanism of tolerance of common bean plants to ethoxysulfuron is enhanced herbicide detoxification.Keywords: Phaseolus vulgaris, crop grain yield, ALS enzyme, detoxification. RESUMO -Os objetivos deste trabalho foram determinar o efeito do herbicida ethoxysulfuron sobre o desenvolvimento do feijoeiro (Phaseolus vulgaris), avaliar o impacto do herbicida sobre o rendimento de grãos e determinar o mecanismo de tolerância do feijoeiro ao ethoxysulfuron. Em campo, foram realizados dois experimentos com doses crescentes de ethoxysulfuron, a fim de determinar o seu efeito sobre o desenvolvimento e o rendimento de grãos de dois cultivares (cvs.) de feijão (IPR Andorinha e IPR Tangará). O mecanismo de tolerância das plantas foi determinado através da análise de sensibilidade da enzima ALS ao herbicida, do uso de inseticidas inibidores da P450 (malathion + chlorpyrifos) e do uso de antídoto (mefenpyr-diethyl). Quando a dose de ethoxysulfuron foi de 83,2 g ha -1 , as perdas de rendimento de grãos atingiram 25% (IPR Tangará) e 35% (IPR Andorinha

Characterization of Ethoxysulfuron Herbicide Selectivity in Common Bean Cultivars

“…In cultivated plants, the metabolization of the herbicide molecule by specific enzymes, such as P450 mono-oxygenases and Glutathione-S-Transferase (Werck-Reichhart et al, 2000;Powles and Yu, 2010) stands out. Previous studies have shown that the main mechanism involved in bean tolerance to ethoxysulfuron is the metabolization of the herbicide molecule (Pagnoncelli Jr. et al, 2016). Overall data corroborate the hypothesis that bean cultivars have a differential capacity to metabolize ethoxysulfuron.…”

“…In Brazilian literature, there are few studies that demonstrate the different tolerance of bean cultivars to herbicides, especially ALS inhibiting herbicides. Recent studies have demonstrated that ethoxysulfuron is selective to bean crops (Assis et al, 2014;Pagnoncelli Jr. et al, 2016). However, as it happens to other cultivated species, it is believed that there is a different tolerance of bean cultivars to the herbicide.…”

Response of Wheat Plants to Combinations of Herbicides with Insecticides and Fungicides

“…The effect is reported mainly when herbicides inhibiting acetolactate synthase (ALS), some of photosystem II (PSII; bentazon and propanil), and acetyl CoA carboxylase (ACCase) 3 are combined with insecticides from the organophosphorus and carbamate groups (McRae et al, 1964;Matsunaka, 1968;Campbell and Penner, 1982;Biediger et al, 1992;Baerg et al, 1996;Ahrens and Panara, 1997). Studies have indicated that the combination of the herbicide ethoxysulfuron with organophosphorus insecticides (malathion + chlorpyrifos) increased injuries caused by herbicide on the bean crop when compared to the isolated herbicide application (Pagnoncelli Jr et al, 2016). Similar results have been observed in corn with the combination of nicosulfuron and chlorpyrifos (Silva et al, 2005), as well as in wheat with the application of imazamox and malathion (Rojano-Delgado et al, 2015).…”

Ethoxysulfuron no controle de plantas daninhas na cultura do feijoeiro comum

“…Em conjunto, estes dados demonstram que as plantas de feijão possuem alta capacidade de recuperação do efeito do herbicida. Em trabalhos conduzidos avaliando o mecanismo de tolerância das plantas de feijão ao ethoxysulfuron, através do uso de inibidores da metabolização (malathion+chlorpyrifos) e protetor (mefenpyr-diethyl), constatou-se que o principal mecanismo envolvido é a metabolização da molécula do herbicida (Pagnoncelli Jr et al, 2016).…”