Expression of defence-related genes in sugar beet plants infected with Rhizoctonia solani and treated with benzo-(1,2,3)-thiadiazole-7-carbothioic acid S-methyl ester (BTH)

• Main Author: Maios, Claudia.
• Format: Others
• Language: en
• Published: McGill University 2006
• Subjects: Sugar beet > Disease and pest resistance.; Rhizoctonia solani.
• Online Access: http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=99349

The chemicals inducers SA, BABA, and BTH were tested as seed treatment and soil drench on a partial-resistant cultivar of sugar beet grown in sand infested with the Rhizoctonia solani AG 2-2IIIB. In another series of experiments, BTH was applied as soil drench on sugar beet plants inoculated with R. solani. The chemical inducers were ineffective in reducing pre-emergence damping-off and post-emergence plant mortality. Despite these results, treatment with BTH altered the levels of expression ratios of four defence encoding genes associated with systemic resistance: chitinase, peroxidase, chalcone isomerase, and chalcone synthase. BTH sensitised sugar beet plants without the necessity of R. solani infection to up-regulate substantially the transcript level ratios of chalcS and chit3, while levels of chalcI were down-regulated levels below 1. Of interest, was the significant increase of transcript levels of chit3 in sugar beet plants infected with R. solani and treated with BTH. In conclusion, sugar beet plants were capable of over expressing selected genes in response to a chemical inducer, but contrary to what had been reported, gene activation in sugar beet as a result of BTH treatment does not confer disease resistance against R. solani.