Herbivore induced plant volatiles (HIPV) have been reported to play an important role in plant defense priming against insect herbivores. In an attempt to identify the actual volatile component that primes plant defense, most studies used synthetic compounds at high concentrations, which lead to controversies for many years. Using transgenic plants impaired in their ability of emitting certain volatile groups will help to dissect the role of specific volatiles in defense priming. In this study, we used N. benthamiana plants with VIGS-silenced Green Leaf Volatile (GLV) biosynthetic pathway (i.e, LOX3 gene) to study the potential of GLV as volatile signal to prime plant defenses in neighboring plants. We used insects’ behavioral and physiological responses to measure the plant defense status, and plants’ growth and reproductive fitness to measure costs/benefits associated with priming. Our data demonstrate that when GLV production is silenced in emitter plants, receiver plants did not get primed for enhanced production of defense metabolites, such as terpenes and JA. However, exposure to realistic concentrations of (Z)-3-hexenol alone primed receiver plants for both JA and terpene production. Together, these results suggest that GLV are necessary and (Z)-3-hexenol alone is sufficient to prime receiver plants for enhanced production of defensive volatiles and JA. We also assessed how this defense priming affects insects’ performance and growth and reproductive fitness of receiver plants. M. sexta larvae consumed less leaf materials and grew poorly on tobacco plants exposed to (Z)-3-hexenol or HIPV. In addition, we observed no cost of defense priming in N. benthaminana. (Z)-3-hexenol-exposed plants were similar to unexposed plants in their growth and development and even better than unexposed plants in their number of seed capsules. Together, our study suggests (Z)-3-hexenol alone is sufficient to prime plants for better defense without compromising their ability to grow and reproduce.

Exposure to (Z)-3-hexenol primes tobacco plants for faster and stronger defense without negatively affecting their ability to grow and reproduce

ACS Fall 2021

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.