Biochemical responses of suspension-cultured sugarcane cells to an elicitor derived from the root pathogen Pachymetra chaunorhiza

The fungus Pachymetra chaunorhiza Croft & Dick causes a root rot in sugarcane (Saccharum interspecific hybrid). Suspension-cultured sugarcane cells prepared from cultivars Q114 (P. chaunorhiza resistant) and Q90 (P. chaunorhiza susceptible) were inoculated with a heat-derived elicitor preparation from P. chaunorhiza and the cellular responses monitored by measuring phenylalanine ammonia-lyase (PAL) and peroxidase (POD) activity and the production of additional phenolic compounds. Introduction of the P. chaunorhiza elicitor induced marked changes in the biochemistry of both sugarcane cell lines. Both cell lines produced additional phenolic compounds not present in untreated cells and different compounds were produced by each cell line. Induced enzyme activities also differed between the cell lines with Q90 (susceptible) showing a large and transitory increase in PAL activity that was far greater than that observed for Q114(resistant). POD activity increased more in Q114 than in Q90, although the differences between the resistant and susceptible cell lines were not as great as for PAL.