Influence of low oxygen on root defense mechanisms
Clones of Eucalyptus marginata, resistant or susceptible to the pathogen Phytophthora cinnamomi, were grown in aeroponics chambers that could be sealed to allow the manipulation of oxygen levels. Roots grown under normal oxygen were compared with those that had been exposed to either 6 days of hypoxia (2 mg 02 L-1) or 6 hrs of anoxta (<0.05 mg 02 L-1 ) prior to infection by zoospores of P. cinnamomi. Roots were harvested for temporal and spatial studies on the induction of the defense enzymes phenylalanme ammonia-lyase (PAL), 4-coumerate: CoA ligase (4-CL), cinnamyl alcohol dehydrogenase (CAD) and chalcone isomerase (CI). The resistant clones had higher constitutive levels of all the enzymes examined and responded to infection more rapidly. This resulted in slower lesion extension. Pre-treatment with anoxia resulted in the death of the apical meristem and a reduction in the plant defense response. However, roots of both susceptible and resistant clones, that had been pre-treated with hypoxia, had a more rapid defense response than control roots.
|Publication Type:||Conference Item|
|Murdoch Affiliation:||School of Biological Sciences and Biotechnology|
|Item Control Page|