Tree host-pathogen interactions as influenced by drought timing: linking physiological performance, biochemical...

Area of Science:

• Plant Pathology
• Forest Ecology
• Plant Physiology

Background:

• Global tree mortality is rising due to climate extremes and pathogen shifts.
• Empirical studies on combined biotic and abiotic stress effects on plants are scarce.

Purpose of the Study:

• To investigate the interactive effects of drought stress and canker pathogen (Quambalaria coyrecup) on Corymbia calophylla (marri).
• To test if drought increases susceptibility to canker and if cankers most harm pre-stressed plants.

Main Methods:

• Marri saplings were subjected to glasshouse experiments with varying drought and pathogen inoculation timings.
• Physiological responses, canker development, and biochemical defenses were measured.

Main Results:

• Canker development was more severe in well-watered saplings, especially those previously exposed to drought.
• Drought reduced photosynthesis and growth, but negative canker impacts on physiology were only seen in well-watered saplings.
• Phenol-based defenses were observed across all water treatments.

Conclusions:

• The timing of drought stress significantly influences host physiology and disease susceptibility.
• Host condition, modulated by drought, affects biochemical defense mechanisms against pathogens.
• Understanding stress interactions is vital for predicting tree mortality in drought-affected areas.