New Inspiration of 1,3,4-Oxadiazole Agrochemical Candidates: Manipulation of a Type III Secretion System-Induced Bacterial Starvation Mechanism to Prevent Plant Bacterial Diseases

Abstract

Discovering new anti-virulent agents to control plant bacterial diseases by preventing bacterial pathogenesis/ pathogenicity rather than affecting bacterial growth is a sensible strategy. However, the effects of compound-manipulated bacterial virulence factors on host response are still not clear. In this work, 35 new 1,3,4-oxadiazole derivatives were synthesized and systematically evaluated for their anti-phytopathogenic activities. Bioassay results revealed that compound C 7 possessed outstanding antibacterial activity in vitro (half-maximal effective concentration: 0.80 μg/mL) against Xanthomonas oryzae pv. oryzae (Xoo) and acceptable bioactivity in vivo toward rice bacterial leaf blight. Furthermore, virulence factor-related biochemical assays showed that C 7 was a promising anti-virulent agent. Interestingly, C 7 could indirectly reduce the inducible expression of host SWEET genes and thereby alleviate nutrient supply in the infection process of phytopathogenic bacteria. Our results highlight the potential of 1,3,4oxadiazole-based agrochemicals for manipulating type III secretion system-induced phytopathogenic bacteria starvation mechanisms to prevent plant bacterial diseases.

Design, Synthesis, Antibacterial Activity, and Mechanisms of Novel Benzofuran Derivatives Containing Disulfide Moieties

“…In recent years, 1,3,4-oxadiazole-containing structures have aroused widespread awareness from many researchers because of their broad spectrum and highly effective antibacterial activities against plant pathogens. − In addition, disulfide (S–S) is an extremely promising chemical moiety frequently found in the structure of many naturally occurring small molecules and proteins (Figure b). For instance, ethylicin (ET) is a bionic bactericide inspired by allicin in garlic .…”

An insight into pathogenicity and virulence gene content of Xanthomonas spp. and its biocontrol strategies

“…It may indirectly suppress the inducible activation of host SWEET genes ( Fig. 3 ), thus mitigating sucrose availability during the infection process to the phytopathogenic bacteria, thereby being used as a biocontrol agent in agriculture [ 157 ]. Phenazine-1-carboxylic acid which is a bioactive compound of Pseudomonas is formulated under the trade name of shenqinmycin and is globally used as a biopesticide to control Xanthomonas infection.…”

Discovery of Novel Compounds for Combating Rising Severity of Plant Diseases Caused by Fungi and Viruses

“…The 1,3,4-oxadiazole skeleton, a class of heterocyclic compounds containing two N atoms, is widely utilized as a fundamental building block in natural products and pharmaceutical molecules due to its remarkable biological and pharmacological activities. − Therefore, the development of synthetic methodologies for 1,3,4-oxadiazole frameworks has consistently been a focal point of research in the chemical community. Notable commercially available pesticides containing a 1,3,4-oxadiazole moiety include oxadiazon and metoxadiazone.…”