Indaziflam Herbicidal Action: A Potent Cellulose Biosynthesis Inhibitor      

Abstract

Cellulose biosynthesis is a common feature of land plants. Therefore, cellulose biosynthesis inhibitors (CBIs) have a potentially broad-acting herbicidal mode of action and are also useful tools in decoding fundamental aspects of cellulose biosynthesis. Here, we characterize the herbicide indaziflam as a CBI and provide insight into its inhibitory mechanism. Indaziflam-treated seedlings exhibited the CBI-like symptomologies of radial swelling and ectopic lignification. Furthermore, indaziflam inhibited the production of cellulose within ,1 h of treatment and in a dose-dependent manner. Unlike the CBI isoxaben, indaziflam had strong CBI activity in both a monocotylonous plant (Poa annua) and a dicotyledonous plant (Arabidopsis [Arabidopsis thaliana]). Arabidopsis mutants resistant to known CBIs isoxaben or quinoxyphen were not cross resistant to indaziflam, suggesting a different molecular target for indaziflam. To explore this further, we monitored the distribution and mobility of fluorescently labeled CELLULOSE SYNTHASE A (CESA) proteins in living cells of Arabidopsis during indaziflam exposure. Indaziflam caused a reduction in the velocity of YELLOW FLUORESCENT PROTEIN:CESA6 particles at the plasma membrane focal plane compared with controls. Microtubule morphology and motility were not altered after indaziflam treatment. In the hypocotyl expansion zone, indaziflam caused an atypical increase in the density of plasma membrane-localized CESA particles. Interestingly, this was accompanied by a cellulose synthase interacting1-independent reduction in the normal coincidence rate between microtubules and CESA particles. As a CBI, for which there is little evidence of evolved weed resistance, indaziflam represents an important addition to the action mechanisms available for weed management.

Identification of MEDIATOR16 as the Arabidopsis COBRA suppressor MONGOOSE1

“…Uniformly 13 C-labeled primary cell walls were prepared and analyzed by NMR (57,58). Cellulose biosynthesis inhibitor assays (45) and monosaccharide and cellulose analyses were performed as previously described (59). Pectin esterification was measured as previously reported (60).…”

“…However, sfr6 mutants were shown to be hypersensitive to freezing, as well as to osmotic stress (44). To test the response of sfr6-3 to perturbations in cellulose synthesis, we performed cellulose biosynthesis inhibitor assays (Table 2) using inhibitors with different effects on the cellulose synthase complex (45).…”

Influence of soil properties and soil moisture on the efficacy of indaziflam and flumioxazin onKochia scopariaL.

“…Indaziflam [ N ‐[(1 R ,2 S )‐2,3‐dihydro‐2,6‐dimethyl‐1 H ‐inden‐1‐yl]‐6‐[(1 RS )‐1‐fluoroethyl]‐1,3,5‐triazine‐2,4‐diamine] is a selective alkylazine herbicide used for broad‐spectrum PRE control of over 75 grass, broadleaf and annual sedge species . Indaziflam is a cellulose biosynthesis inhibitor, a new site of action for kochia control, and is used in industrial vegetative management, turf and established citrus, grape and tree nut crops . Application rates range between 51 and 102 g AI ha −1 , with a yearly maximum of 146 g AI ha −1 .…”

CESA TRAFFICKING INHIBITOR Inhibits Cellulose Deposition and Interferes with the Trafficking of Cellulose Synthase Complexes and Their Associated Proteins KORRIGAN1 and POM2/CELLULOSE SYNTHASE INTERACTIVE PROTEIN1

“…The first is characterized by the depletion of CESAs from the PM and their accumulation in cytosolic compartments, as observed for the herbicide isoxaben {N-[3-(1-ethyl-1-methylpropyl)-5-isoxazolyl]-2,6-dimethyoxybenzamide}, CGA 325615 [1-cyclohexyl-5-(2,3,4,5,6-pentafluorophe-noxyl)-1l4,2,4,6-thiatriazin-3-amine], thaxtomin A (4-nitroindol-3-yl containing 2,5-dioxopiperazine), AE F150944 [N2-(1-ethyl-3-phenylpropyl)-6-(1-fluoro-1-methylethyl)-1, 3,5-triazine-2,4-di-amine], and quinoxyphen [4-(2-bromo-4,5-dimethoxyphenyl)-3,4-dihydro-1 H-benzo-quinolin-2-one]; (Paredez et al, 2006;Bischoff et al, 2009;Crowell et al, 2009;Gutierrez et al, 2009;Harris et al, 2012). The second displays hyperaccumulation of CESAs at the PM, as seen for the herbicides dichlobenil (2,6-dichlorobenzonitrile) and indaziflam {N- (Herth, 1987;DeBolt et al, 2007b;Brabham et al, 2014). The third exhibits disturbance of both CESAs and MTs and alters CESA trajectories at the PM, as exemplified by morlin (7-ethoxy-4-methylchromen-2-one; DeBolt et al, 2007a).…”