Abstract
Citrus bacterial canker, caused by Xanthomonas citri subsp. citri (Xcc), is a destructive disease. So far used chemicals to control this pathogen are either not effective or have harmful effects on the environment. To improve control of this disease, lime (Citrus aurantifolia) plants inoculated with Xcc were treated with β-Aminobutyric Acid (BABA), ascorbic acid (vitamin C), thiamin (vitamin B1), green tea (Camellia sinensis), copper oxychloride and distilled water. Lesion diameters of inoculated leaves were evaluated twenty days after treatment. The results showed that BABA and green tea had inhibitory effects on disease development. None of the agents used for plant treatment had direct antimicrobial activity on Xcc, except copper oxychloride. This indicated that the inhibitory effects of BABA and green tea resulted from strengthening the defense capacities of the plant. To support this claim, partial coding sequences of Pathogenesis-Related (PR) genes from lime were cloned and sequenced. Analysis of PR gene expression showed increased mRNA levels of β-1,3-glucanase and chitinase, during disease development. Reduction in lesion size and lack of antimicrobial activity indicate that BABA and green tea might be useful treatments against Xcc infection.
Highlights
Asiatic citrus canker, caused by the endophytic bacterium Xanthomonas citri subsp
We inoculated citrus leaves with Xanthomonas citri subsp. citri (Xcc) and after first symptoms became visible attempted to reduce their spread by spray-treatment of the inoculated leaves with BABA 250 ppm, vitamin C 1.5 mM, green tea 0.58% (w/v), copper oxychloride 0.6%, vitamin B1 50 mM, SA 2 mM
Our results showed that spray treatment with green tea and BABA reduced lesion size by about 50% as compared to the water control
Summary
Asiatic citrus canker, caused by the endophytic bacterium Xanthomonas citri subsp. The pathogen causes lesions on leaves, twigs and fruits which later develop into white or yellow spongy pustules. These pustules become darker and thicker and turn into brown corky cankers which are often surrounded by water-soaked margins. Copper Ammonium Carbonate (CAC) with 8% copper content was consistently the most effective agent in controlling Xcc (Mur et al, 1996). CAC is a contact poison and used to achieve adequate control on susceptible citrus hosts such as grapefruit and sweet orange (Graham et al, 2004; Schubert et al, 2001; Leite Jr et al, 1987).
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
