Indução de respostas de defesa cruzada em Solanum tuberosum utilizando indutores de resistência contra patógenos

Abstract

Rhizoctonia solani is a pathogenic ubiquitous fungus in Solanum tuberosum cultures, causing severe losses in production. Plant resistance can be induced by molecules that promote natural plant defense system. In the present study, the efficiency of the inducers Acibenzolar-Smethyl (BION®), Ceratocystis fimbriata extract and Xanthomonas axonopodis extract against the pathogenic fungus Rhizoctonia solani in potato plants was evaluated. Plants treated with the inducer XTH were resistant to the pathogen at 21 dpi. The biotic inducer XTH was more efficient than Bion® and CTS on promoting plant resistance. The highest activity of POX was observed at 9 dpi on the XTH treatment. Inoculation of R. solani caused a progressive increase in the PPO activity in XTH- and control-plants. Both inducers CTS and Bion® caused a reduction on PPO activity over time. Levels of phenolics compounds and flavonoids were similar among all treatments. Plants were more susceptible to R. solani when induced with CTS or Bion®. XTH did not show a negative effect on plant resistance. XTH presented a good potential as inducer, delaying disease progression and promoting plant resistance against R. solani.