[poster] Interactive effects of drought severity and herbivory on tea (Camellia sinensis) volatile and non-volatile metabolites.


Plants often experience multiple sources of stress simultaneously, yet little is known about interactive effects of multiple stressors on plant metabolic responses. Plants are well known to respond to both drought and insect herbivory through the induced production of secondary metabolites. When challenged with both sources of stress, redundancy in these metabolic responses or hormonal crosstalk may lead to priming of herbivore-induced responses by drought. On the other hand, severe drought stress also reduces photosynthetic activity, reducing the carbon pool available for production of secondary metabolites, which could inhibit herbivore-induced responses under drought conditions. We tested the interactive effects of drought stress and simulated herbivory in tea plants (Camellia sinensis) grown under varying rainfall interception treatments that were subsequently exposed to an exogenous methyl jasmonate (MeJA) treatment. Here, we show that tea plants experiencing severe drought are unable to respond to simulated herbivory (exogenous MeJA) through induced volatile and non-volatile production when they are severely drought stressed, although they respond as expected under moderate drought stress. Specifically, we find that the majority of volatile metabolites induced by MeJA in moderately stressed plants are not induced or reduced in concentration by MeJA application in severely drought stressed plants. However, a minority of volatile metabolites are induced more strongly in severely drought stressed tea plants. In addition to having implications for plant–herbivore interactions in the presence of abiotic stress, these results have important implications for tea quality.

Vancouver, BC, Canada