Plant viral diseases cause the loss
of millions of dollars to agriculture
around the world annually. Therefore, the development of highly efficient,
ultra-low-dosage agrochemicals is desirable for protecting the health
of crops and ensuring food security. Herein, a series of 1,3,4-oxadiazole
derivatives bearing an isopropanol amine moiety was prepared, and
the inhibitory activity against tobacco mosaic virus (TMV) was assessed.
Notably, compound A14
exhibited excellent
anti-TMV protective activity with an EC50 value of 137.7
mg L–1, which was superior to that of ribavirin
(590.0 mg L–1) and ningnanmycin (248.2 mg L–1). Moreover, the anti-TMV activity of some compounds
could be further enhanced (by up to 5–30%) through supplementation
with 0.1% auxiliaries. Biochemical assays suggested that compound A14
could suppress the biosynthesis of TMV and
induce the plant’s defense response. Given these merits, designed
compounds had outstanding bioactivities and unusual action mechanisms
and were promising candidates for controlling plant viral diseases.