Inheritance of Resistance to Protoporphyrinogen Oxidase Inhibitor Herbicides in Wild Poinsettia

Abstract

-Weed resistance to herbicides is a major global problem for agriculture. In recent years, the increased use of herbicides, without proper planning, has led to a large increase in the number of cases of weed biotypes that are resistant to one or more herbicide mechanism of action. Wild poinsettia biotypes (Euphorbia heterophylla), discovered in the State of Paraná, with resistance to herbicides that inhibit protoporphyrinogen oxidase (PROTOX) and acetolactate synthase (ALS), are the first case to exhibit multiple resistance in Brazil. This study analyzed the genetic inheritance of PROTOX inhibiting herbicide resistance in E. heterophylla. Crosses were conducted between biotypes that were susceptible (female parent) and those carrying multiple resistance to ALS and PROTOX inhibitors (male parent) to obtain the F 1 generation. Backcrosses were performed (RC 1 and RC 2 ) and the F 1 generation was advanced to F 2 . F 1 , F 2 , RC 1 , RC 2 generation plants and their parents were subjected to applications of the herbicide fomesafen (250 g i.a. ha -1 ). The observed frequencies in the F 2 generation were not different from the expected frequency of 3:1. All RC 2 individuals were resistant, while the RC 1 population showed a 1:1 segregation, which would be expected when a single gene controls the trait. Thus, it can be inferred that E. heterophylla resistance to PROTOX-inhibiting herbicides is conditioned by a single and dominant nuclear gene.

Arg-128-Leu target-site mutation in PPO2 evolves in wild poinsettia (Euphorbia heterophylla) with cross-resistance to PPO-inhibiting herbicides

“…Mutations in the same amino acid position were previously found in A. artemisiifolia and A. palmeri resistant to PPO inhibitors (Giacomini et al 2017;Sarangi et al 2019). Inheritance studies conducted with other E. heterophylla populations showed a single nuclear and dominant gene involved with PPO-inhibitor resistance (Brusamarello et al 2016). A single and dominant resistance allele supports our results for a target-site mutation as the only mechanism of resistance.…”

Origins and structure of chloroplastic and mitochondrial plant protoporphyrinogen oxidases: implications for the evolution of herbicide resistance

“…As is the case with A. tuberculatus, PPO-inhibitor resistance in E. heterophylla exhibits broad cross-resistance and is conferred by a single, (partially) dominant, nuclear gene. 33,34 Trezzi et al suggested that resistance could be attributable to differential leaf absorption, but this has yet to be confirmed. 35 There are at least a couple of cases in which resistance to PPO inhibitors probably occurred as a result of selection by herbicides with different target sites.…”

“…Additionally, some mechanistic work has been reported for Euphorbia heterophylla , the second weed species identified with resistance to PPO inhibitors (Table ). As is the case with A. tuberculatus , PPO‐inhibitor resistance in E. heterophylla exhibits broad cross‐resistance and is conferred by a single, (partially) dominant, nuclear gene . Trezzi et al .…”

Weed control in melon with preemergence herbicides

“…Fenoxaprop-P-ethyl is a herbicide inhibitor of the enzyme acetyl-coenzyme, a carboxylase (ACCase inhibitor) that acts in the postemergence control of grasses (Takano et al, 2020). Clomazone is a synthase inhibitor (DOXP inhibitor), which is a pivotal component for plastid isoprenoid synthesis (Cabral et al, 2017), whereas carfentrazone-ethyl causes the inhibition of the protoporphyrinogen oxidase enzyme (PPO inhibitor) (Brusamarello, 2016). The commercial premix of clomazone + carfentrazone-ethyl is registered for the pre-and postemergence control of grass and broadleaf weeds in several crops.…”