AUTHOR=Yao Lin , Zhang Guanghua , Yu Lili , Liu Shaojing , Wang Xiaoku , Fan Tao , Kang Hui , Feng Wenzhi 

TITLE=Development of 1,3,4-Oxadiazole Derived Antifungal Agents and Their Application in Maize Diseases Control

JOURNAL=Frontiers in Plant Science

VOLUME=Volume 13 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/plant-science/articles/10.3389/fpls.2022.912091

DOI=10.3389/fpls.2022.912091

ISSN=1664-462X

ABSTRACT=<p>Maize is an important food crop and its fungal disease has become a limiting factor to improve the yield and quality of maize. In the control of plant pathogens, commercial fungicides have no obvious effect on corn diseases due to the emergence of drug resistance. Therefore, it is of great significance to develop new fungicides with novel structure, high efficiency, and low toxicity to control maize diseases. In this paper, a series of 1,3,4-oxadiazole derivatives were designed and synthesized from benzoyl hydrazine and aromatic aldehydes through condensation and oxidation cyclization reaction. The antifungal activity of oxadiazole derivatives against three maize disease pathogens, such as <italic>Rhizoctonia solani</italic> (<italic>R. solani</italic>), <italic>Gibberella zeae</italic> (<italic>G. zeae</italic>), and <italic>Exserohilum turcicum</italic> (<italic>E. turcicum</italic>), were evaluated by mycelium growth rate method <italic>in vitro</italic>. The results indicated that most of the synthesized derivatives exhibited positive antifungal activities. Especially against <italic>E. turcicum</italic>, several compounds demonstrated significant antifungal activities and their <italic>EC</italic><sub>50</sub> values were lower than positive control carbendazim. The <italic>EC</italic><sub>50</sub> values of compounds 4k, 5e, and 5k were 50.48, 47.56, 32.25 μg/ml, respectively, and the carbendazim was 102.83 μg/ml. The effects of active compounds on <italic>E. turcicum</italic> microstructure were observed by scanning electron microscopy (SEM). The results showed that compounds 4k, 5e, and 5k could induce the hyphae of <italic>E. turcicum</italic> to shrink and collapse obviously. In order to elucidate the preliminary mechanism of oxadiazole derivatives, the target compounds 5e and 5k were docked with the theoretical active site of succinate dehydrogenase (SDH). Compounds 5e and 5k could bind to amino acid residues through hydrophobic contact and hydrogen bonds, which explained the possible mechanism of binding between the inhibitor and target protein. In addition, the compounds with antifungal activities had almost no cytotoxicity to MCF-7. This study showed that 1,3,4-oxadiazole derivatives were worthy for further attention as potential antifungal agents for the control of maize diseases.</p>