Fungicidal Effect of Pyraclostrobin against Botrytis cinerea in Relation to Its Crystal Structure

Abstract

Pyraclostrobin (PYR) is a commonly used strobilurin fungicide, which inhibits mitochondrial respiration at the ubiquinol oxidation center site of the cytochrome bc1 complex. Little information is available regarding the crystal structure of PYR on its fungicidal effect. In this study, the crystal structures of eight PYRs (PYR-A to H) from different sources are determined by using high-resolution X-ray powder diffraction (XRPD) and model construction with the Pawley refinement module. The effects of PYRs on mycelium growth, the kinetics of mycelial growth, conidial germination, and tube elongation of conidia of Botrytis cinerea from tomato are compared. The level of organic acids in the mitochondrial tricarboxylic acid cycle of PYR-treated B. cinerea is analyzed. The results show that PYR-A to PYR-H have their own unique character of XRPD patterns, but the crystal morphology of eight PYRs presents in the triclinic crystal system and space group P1̅ . PYR-D with the eclipsed conformation and rational edge angles α (72.599°) and β (98.612°) in the crystal cell shows the highest inhibitory effect against mycelium growth with EC 50 as 3.383 μg mL −1 , the best time-dependent effects on the mycelium growth kinetics, and the strongest inhibition on tube elongation of conidia, whereas PYR-E with anticonformation is the worst. Moreover, a significant accumulation of fumarate, malate, and oxalate in the PYR-D-treated mycelium is observed. These findings reinforce the need for a definite crystal structure of PYR to limit usage and mitigate future selection pressure for gray mold management.

Fungicidal activity of novel quinazolin‐6‐ylcarboxylates and mode of action on Botrytis cinerea

“…The phytopathogenic fungi species were isolated from agricultural locations within Shanghai suburbs in the past and they have been maintained and used for bioassays as needed. Botrytis cinerea was isolated from tomato, Sclerotinia sclerotiorum was isolated from rape, Fusarium graminearum was isolated from wheat, and F. oxysporum was isolated from cucumber 19,20 . Other phytopathogenic fungi Sclerotium rolfsii , Exserohilum rostratum and Botryosphaeria dothidea were obtained from Shanghai Institute of Pesticide Research 21 .…”

“…Botrytis cinerea was isolated from tomato, Sclerotinia sclerotiorum was isolated from rape, Fusarium graminearum was isolated from wheat, and F. oxysporum was isolated from cucumber. 19,20 Other phytopathogenic fungi Sclerotium rolfsii, Exserohilum rostratum and Botryosphaeria dothidea were obtained from Shanghai Institute of Pesticide Research. 21 In addition to storing at −80 °C in RPMI buffer-glycerol mixture, the fungi species are continuously cultured for experimental use.…”

“…The production of oxalic acid in B. cinerea mycelia was determined using the ion chromatography method. 20 The mycelia were incubated in shaking PDB media supplemented with 0 (control), 12.5, 25.0, and 50.0 μg mL −1 of compounds F08, F13, and F17 at 25 °C for 48 h, and then harvested, rinsed thrice with distilled water, and dried with absorbent paper. The dried fresh mycelia at 0.1 g was then grinded with 1.0 mL of 0.5 mol L −1 trifluoroacetic acid.…”

Comprehensive Overview of β-Methoxyacrylate Derivatives as Cytochrome bc1 Inhibitors for Novel Pesticide Discovery

“…The pyrazole ring is a significant scaffold in heterocyclic compounds due to outstanding biological activities such as antifungal, antimicrobial, anticancer, antitubercular, antiviral, and antileishmanial activities . Pyraclostrobin, containing a pyrazole ring as the side chain, has become one of the most heavily and long used agricultural fungicides because of remarkable fungicidal activity and broad-spectrum properties since its introduction to the market in 2003, and the sale of pyraclostrobin has significantly promoted the market development of other β-methoxyacrylate fungicides . So the pyrazole ring could be employed as a promising side chain for discovery of novel β-methoxyacrylate fungicides.…”

Construction and application of a qualitative and quantitative analysis system of three boscalid polymorphs based on solid-state analytical methods and chemometric tools

“…2 In the agrochemical field, many studies have reported that polymorphs of many active compounds exhibit disparate physical and chemical properties, which could affect the follow-up process and the amount of agrochemical use. [3][4][5][6][7][8] For example, de Villiers et al discovered four forms of amitraz and found that different forms would lead to different stability of its suspensions. 3 Yang et al reported form II of 1,1,1-trichloro-2,2-bisIJ4-chlorophenyl)ethane (DDT) and confirmed that form II had better insecticidal activities than form I, which could provide opportunities to reduce DDT usage and protect the environment.…”