Inhibition of the Citrus Canker Pathogen Using a Photosensitizer Assisted by Sunlight Irradiation

Abstract

Citrus canker, induced by bacterial infection, seriously affects the growth and productivity of citrus around the world and has attracted strong research interest. The current treatment for this disease uses copper salts to inactivate the pathogenic bacteria: Xanthomonas citri subsp. citri ( Xcc ) strain. However, copper salts may have a negative impact on the environment or plant. In this work, we identify a chemical compound, 2,6-diiodo-1,3,5,7-tetramethyl-8-(P-benzoic acid)-4,4′-difluoroboradiazaindacene (DIBDP), to inactivate the pathogenic Xcc strain ( 29-1 ). DIBDP is activated by sunlight and generates reactive oxygen species to kill the bacteria. In order to overcome the degradation of DIBDP under sunlight, an adjuvant agent was identified to limit the photodegradation of DIBDP by forming a photosensitizer complex (PSC). This complex demonstrated significant antimicrobial activity to Xcc 29-1 , which was 64-fold more potent than the copper biocides. The antimicrobial efficacy of PSC on citrus leaves infected by Xcc 29-1 also was much stronger than copper agent and, at the same time, the PSC was safe to the host exposed to sunlight. Thus, this PSC is a promising antibacterial agent to control citrus canker disease.

A whole-course-repair system based on ROS/glucose stimuli-responsive EGCG release and tunable mechanical property for efficient treatment of chronic periodontitis in diabetic rats

“…After 24 hours co-culture experiments of hydrogels and bacteria according to the above method, the bacteria were transferred onto silicon wafers and fixed with pre-cooling 2.5% (v/v) glutaraldehyde in PBS overnight at 4 1C. 40,64 Next, the bacteria were dehydrated in a series of ethanol (30,50,70,90, 100%) for about 10-15 minutes at each step. Then, the dehydrated bacteria were dried at 37 1C overnight.…”

A look at photodynamic inactivation as a tool for pests and vector-borne diseases control

“…Jiang et al [67] (Entry 5, table 1) evaluated the efficiency of 2,6-diiodo-1,3,5,7-tetramethyl-8-(P-benzoic acid)-4,4 ′difluoroboradiazaindacene (DIBDP) and its association with adjuvants to forms photosensitizer complex (PSC) preventing degradation with radiation and inactivating Xanthomonas citri subsp. citri strain (Xcc 29-1) which causes citrus canker.…”

Clarification of the infection pattern of Xanthomonas citri subsp. citri on citrus fruit by artificial inoculation

“…Citrus is one of the most important cash crops in the world and occupies the leading position of fruit production globally. However, the global citrus industry faces significant threats, with citrus canker being one of the most serious challenges and a key worldwide quarantine disease [ 1 – 3 ]. The pathogen responsible for citrus canker is a Gram-negative bacterium, Xanthomonas citri subsp.…”