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Flavonoids are polyphenolic secondary metabolites that function as signaling molecules, allopathic compounds, phytoalexins, detoxifying agents and antimicrobial defensive compounds in plants. Blast caused by the fungus Magnaporthe oryzae is a serious disease affecting rice cultivation. In this study, we revealed that a natural flavonoid, tangeretin, substantially delays the formation of M. oryzae appressoria and blocks the development of blast lesions on rice plants. Our data suggest that tangeretin has antioxidant activity that interferes with conidial cell death/ferroptosis, which is critical for M. oryzae pathogenicity. Tangeretin showed a ferroptosis inhibition efficacy comparable to the well‐established liproxstatin‐1. Furthermore, overexpression of the NADPH oxidases NOX1 or NOX2 significantly decreased sensitivity toward tangeretin treatment, suggesting Nox‐mediated lipid peroxidation as a possible target for tangeretin in regulating redox signaling and ferroptosis in M. oryzae. Our nursery and field tests showed that application of tangeretin can effectively mitigate overall disease symptoms and prevent leaf blast. Our study reveals the plant‐derived fungal ferroptosis inhibitor tangeretin as a potential and novel antifungal agrochemical for the sustainable prevention of the devastating blast disease in important cereal crops.

:A new series of high-solids [low-VOC (volatile organic compound)content] mar resistant clearcoats (CL-series) were prepared upon crosslinking of a new-synthesized hydroxyl-terminated isophthalate-based liquid oligoester (L-311) with an hexakis(methoxymethylol)melamine (HMMM) resin, via an acid-catalyzed etherification reaction. The chemical, physical, and mechanical properties of the CL-clearcoats were compared to those of a reference clearcoat (CRO). An attempt was made to investigate the effect that the amounts of catalyst and melamine resin had on the clearcoats' physical, chemical, and mechanical properties, and moreover, to correlate these properties to the films chemical structures. The new-formulated high-solids clearcoats (CL-series) presented enhanced processability and higher NVW values (lower VOC content) than the reference clearcoat CRO, and their properties (pencil hardness, knoop hardness, adhesion, impact resistance, solvent and gasoline resistance, mar resistance, and flexibility) were better or comparable to those of the CRO. More specifically, the mar resistance of the CL-clearcoats series was investigated by applying both the crockmeter test and a novel method that employed a modified scanning probe microscope. In addition, we identified and characterized the different responses of the CRO and certain CL-clearcoats to marring stress. The experimental data regarding the mar resistance of the new-formulated clearcoats fully justified our polymer design strategy, verifying our expectations for the possibility of preparing glossy, high-solids mar-resistant clearcoats that could present enhanced processability and solvent resistance, relatively high pencil hardness, and at the same time very good elastic recovery to marring stress.

N-Acylhomoserine lactone (AHL) and diffusible signal factor (DSF) molecules are two families of widely conserved quorum sensing (QS) signals. Quorum quenching (QQ) via enzymatic inactivation of QS signals is a promising strategy of biocontrol. In the search for biocontrol agent quenching both AHL and DSF signals, it has been recently identified that DSFquenching biocontrol agent Pseudomonas sp. HS-18 contains at least three genes (aigA, aigB, and aigC) encoding AHL-acylases displaying strong AHL-acylase activities on various AHLs. Among them, AigA and AigC presented broad-spectrum enzyme activity against AHLs, while AigB preferred longer AHLs. Interestingly, transcriptional expression of aigC could be significantly induced by AHL signals. Heterologous expression of aigA−C in Burkholderia cenocepacia and Pseudomonas aeruginosa resulted in drastically decreased AHL accumulation, virulence factor production, biofilm formation, motility, and virulence on plants. Significantly, the two types of QQ mechanisms in HS-18 showed a strong and much desired synergistic effect for enhanced biocontrol potency against AHL-and DSF-dependent pathogens.