Abstract
Rice bacterial leaf blight and leaf streak are two important bacterial diseases of rice, which can result in yield loss. Currently, effective antimicrobials for rice bacterial diseases are still lacking. Thus, to develop highly effective and low-risk bactericides, 31 novel 1,3,4-oxadiazole derivatives containing a cinnamic acid moiety were designed and synthesized. Bioassay results demonstrated that all compounds exhibited good antibacterial activities in vitro. Significantly, compounds 5r and 5t showed excellent antibacterial activities against Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc), with the 50% effective concentration (EC50) values of 0.58 and 0.34, and 0.44 and 0.20 μg/mL, respectively. These compounds were much better than thiodiazole copper (123.10 and 161.52 μg/mL) and bismerthiazol (85.66 and 110.96 μg/mL). Moreover, compound 5t had better protective and curative activities against rice bacterial leaf blight and leaf streak than thiodiazole copper and bismerthiazol in vivo. Simultaneously, the in vivo efficacy of the compounds was demonstrated by real-time quantitative PCR to quantify bacterial titers. In addition, a three-dimensional quantitative structure–activity relationship model was created and presented good predictive ability. This work provides support for 1,3,4-oxadiazole derivatives containing a cinnamic acid moiety as a potential new bactericide for rice bacterial diseases.
Highlights
As the main food crop for more than half of the world’s population, rice is susceptible to a large number of pathogenic microorganisms, which can cause devastating diseases and result in serious loss of production worldwide, threatening global food security [1,2,3]
In rice-growing countries, rice bacterial leaf blight and leaf streak are two important devastating bacterial diseases of rice; they are caused by the pathogens Xanthomonas oryzae pv. oryzae (Xoo) and X. oryzae pv. oryzicola (Xoc), respectively [4,5]
These two kinds of bacterial diseases can occur either individually or collectively, and over the past 30 years, each of them has been shown to result in yield loss of at least 10% of susceptible rice varieties grown on a large scale [4]
Summary
As the main food crop for more than half of the world’s population, rice is susceptible to a large number of pathogenic microorganisms, which can cause devastating diseases and result in serious loss of production worldwide, threatening global food security [1,2,3]. In rice-growing countries, rice bacterial leaf blight and leaf streak are two important devastating bacterial diseases of rice; they are caused by the pathogens Xanthomonas oryzae pv. Oryzicola (Xoc), respectively [4,5] These two kinds of bacterial diseases can occur either individually or collectively, and over the past 30 years, each of them has been shown to result in yield loss of at least 10% of susceptible rice varieties grown on a large scale [4]. The hazards are increasing with the annual expansion of planting areas. Few bactericides, such as bismerthiazol, thiodiazole copper, zinc thiazole, and zhongshengmycin are available for controlling rice bacterial diseases. Rice bacterial leaf blight and leaf streak have not yet been effectively controlled, and the intensive and
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
