Sumatran fleabane (Conyza sumatrensis) resistant to PSI-inhibiting herbicides and physiological responses to paraquat

Abstract

Herbicide-resistant weed management is one of the greatest agricultural challenges in crop production. Thus, the quick identification of resistant-herbicide weeds is extremely important for management. This study aimed to evaluate resistance to PSI-inhibitor herbicides (diquat) of Sumatran Fleabane [(Erigeron sumatrensis (Retz.) E.Walker)] and physiological response to paraquat application. The research was conducted with two E. sumatrensis biotypes, one susceptible and the other with multiple resistance to herbicides from five different modes of action (glyphosate, paraquat, diuron, saflufenacil, and 2,4-D). A dose-response assay was carried out to evaluate herbicide resistance to diquat in paraquat-resistant E. sumatrensis biotype. The enzymatic activities of superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APX), hydrogen peroxide (H2O2) content, and chlorophyll a fluorescence were measured in both biotypes after paraquat (400 g ai ha−1) application. The dose-response assay confirmed resistance of E. sumatrensis to diquat with resistance factor levels of 26-fold and 6-fold for LD50 and GR50 values, respectively, compared with the susceptible biotype. The accumulation of H2O2 occurred faster in the paraquat-susceptible biotype than in the resistant ones. Paraquat treatment caused an increase in SOD and APX activity in the susceptible biotype, but antioxidant enzyme activities were unaffected by paraquat in the resistant one at 5 hours after application (HAA). Chlorophyll a fluorescence increased along the first 4 HAA in both resistant and susceptible biotypes. However, at 24 HAA the resistant biotype showed a decline in fluorescence close to untreated plants while susceptible one died, which can be used to diagnose paraquat resistance at 24 HAA. There is confirmed resistance to diquat in a paraquat-resistant E. sumatrensis biotype. The paraquat-resistant biotype does not induce antioxidative enzymes, as a possible mechanism of resistance to paraquat, but shows a fast recovery of photosynthesis and continuous growth when subjected to paraquat, while the paraquat-susceptible biotype does not survive.

Rapid photosynthetic and physiological response of 2,4-D–resistant Sumatran fleabane (Conyza sumatrensis) to 2,4-D as a survival strategy

“…Seeds of a 2,4-D-susceptible biotype and a 2,4-D-resistant C. sumatrensis with multiple resistance to six herbicides (paraquat, diquat, saflufenacil, diuron, 2,4-D, and glyphosate) (Leal et al 2021;Pinho et al 2019) of C. sumatrensis were originally collected from a site at Assis Chateaubriand-Paraná, Brazil. Two experimental approaches (fixed: simulated natural growth conditions; and variable: temperature and light conditions) were conducted to evaluate the rapid metabolic and physiological responses of these plants to 2,4-D application.…”

“…: Erigeron sumatrensis Retz.] was first reported with multiple resistance to five herbicide (paraquat, saflufenacil, diuron, 2,4-D, and glyphosate) sites of action (Pinho et al 2019) and subsequently to diquat (Leal et al 2021). The resistant biotype shows different responses to each herbicide application, and in this report, we demonstrate a rapid resistance responses to 2,4-D herbicide in this biotype that is not seen when the other five herbicides (or site of action) are applied.…”

“…Photosynthetic traits, such as chlorophyll (Chl) a fluorescence could be used to monitor cases of resistance involving physiological changes in 2,4-D-resistant plants. The use of Chl a fluorescence to monitor resistance has been reported in C. sumatrensis upon paraquat application, with resistant biotypes surviving and showing recovery of the dynamic electron transport chain energy fluxes within a day, while susceptible plants rapidly show great disorder in the photosynthetic apparatus and die within hours after paraquat application (Leal et al 2021). As well, Brunharo and Hanson (2017) reported that in tall windmill grass (Chloris elata Desv.)…”

Comparative Analysis of Tolerance to Salt Stress and Water Deficit in Two Invasive Weeds of the Genus Erigeron (Asteraceae)

“…Besides their negative impacts on crops and natural vegetation due to direct competition, the two species also play a role in transmission of pests and diseases [ 20 ]. In the last two decades several studies have been published on their biology and ecology [ 22 , 25 , 28 , 32 ], genetic variation [ 33 ], allelopathic effects [ 34 ], or resistance to pesticides [ 35 , 36 , 37 , 38 ]. Moreover, their seed germination ecology was analysed [ 22 , 29 , 39 , 40 ] but to our knowledge tolerance to abiotic stresses such as drought and salinity in different growth stages were not previously investigated.…”