Measuring resistance in Eucalyptus marginata to Phytophthora cinnamomi: What factors change disease expression?
Hüberli, D., Tommerup, I.C., Colquhoun, I. and Hardy, G. (2003) Measuring resistance in Eucalyptus marginata to Phytophthora cinnamomi: What factors change disease expression? In: 8th International Congress of Plant Pathology: Solving problems in the real world, (ICPP 2003), 2 - 7 February, Christchurch; New Zealand.
The interaction between Eucalyptus marginata (Jarrah), the dominant and important timber species in jarrah forests, and Phytophthora cinnamomi, is not a co-evolved one. Jarrah appears to have a wide range of variability in resistance to P. cinnamomi in the forest. Jarrah clonal lines resistant (RR) and susceptible (SS) to the pathogen have been produced. Our glasshouse mortality trial showed that the capacity of 73 isolates to cause disease ranged from killing all plants (59 days) to plants being symptomless (182 days). Comparison of branch and root inoculations in situ confirmed that branches are a valid option for testing resistance of young jarrah. No jarrah clonal line (100% =immune) maintained its resistance level in a series of experiments using different inoculation methods, different environmental conditions and when challenged by individuals from a large range of P. cinnamomi isolates. Even the most promising RR line had replicates that became diseased with time in various treatments. To develop robust resistance, further screening work may be required using more isolates varying in their capacity to cause disease and a broader range of environmental conditions that favour the pathogen, particularly at 25-30°C. Jarrah trees are affected by many environmental conditions during their life cycle (500-1000 years). Consequently, clonal lines that survive such rigorous screening may be durably resistant and survive in disease impacted sites.
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|Murdoch Affiliation:||School of Biological Sciences and Biotechnology|
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