Functional PPO2 mutations: co-occurrence in one plant or the same ppo2 allele of herbicide-resistant Amaranthus palmeri in the US mid-south.

Background: Protoporphyrinogen IX oxidase 2 (PPO2) inhibitors are important for the management of glyphosate- and acetolactate synthase-resistant Palmer amaranth [Amaranthus palmeri (S.) Wats.].

Two new PPX2 mutations associated with resistance to PPO-inhibiting herbicides in Amaranthus palmeri.

Background: Resistance to herbicides that inhibit protoporphyrinogen oxidase (PPO) is a widespread and growing problem for weed managers across the midwestern and midsouthern United States. In Amaranthus spp., this resistance is known to be conferred by a glycine deletion at the 210 amino acid (ΔG210) in PPO2.