Biology subjects

Tumlinson, J. H.

Publications and source records attributed to Tumlinson, J. H..

4 recordsLinked to original sources

bioRxiv2026

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

Plants exposed to volatile signals from herbivore-infested neighbors can activate faster and stronger defenses against subsequent herbivore attack, a phenomenon called defense priming. However, the specific volatile components responsible for activating defense priming remain unclear. Here, we examined the role of green leaf volatiles (GLV) by silencing their biosynthesis using virus-induced gene silencing technique. Exposure to full blend of herbivore-induced plant volatiles (HIPV) primed receiver plants for enhanced production of all 5 groups of HIPV (GLV, monoterpenes, sesquiterpenes, aldoximes, and indole). When GLV production was silenced in emitter plants, receiver plants were no longer primed for terpene production. However, exposure to (Z)-3-hexenol (Z3HOL) alone primed receiver plants for terpene production. These results suggest that GLV are necessary, and Z3HOL alone is sufficient, to prime terpene production in receiver plants. Consistent with enhanced resistance, Manduca sexta larvae feeding on Z3HOL-or HIPV-primed plants consumed less leaf tissue and exhibited reduced growth compared with controls. Importantly, priming did not impose fitness costs, as Z3HOL-exposed plants showed normal growth but produced more seed capsules and seeds than control plants. Together, these findings suggest that Z3HOL alone is sufficient to prime plants for better defense without compromising their ability to grow and reproduce.

ecology↗

bioRxiv2024

Stomata: Gatekeepers of Uptake and Defense Priming by Green Leaf Volatiles in plants

Plants adapt to balance growth-defense tradeoffs in response to both biotic and abiotic stresses. Green leaf volatiles (GLVs) are released after biotic and abiotic stresses and function as damage-associated signals in plants. Although, GLVs enter plants primarily through stomata, the role of stomatal regulation on the kinetics of GLVs uptake remain largely unknown. Here, we illustrate the effect of stomatal closure on the timing and magnitude of GLVs uptake. We closed stomata by either exposing plants to darkness or applying abscisic acid, a phytohormone that closes the stomata in light. Then, we exposed maize seedlings to Z-3-hexen-1-ol and compared the dynamic uptake of Z-3-hexen-1-ol under different stomatal conditions. Additionally, we used E-3-hexen-1-ol, an isomer of Z-3-hexen-1-ol not made by maize, to exclude the role of internal GLVs in our assays. We demonstrate closed stomata effectively prevent GLVs entry into exposed plants, even at high concentrations. Furthermore, our findings indicate that reduced GLV uptake impairs GLVs-driven induction of sesquiterpenes biosynthesis, a group of GLV-inducible secondary metabolites, with or without herbivory. These results elucidate how stomata regulate the perception of GLV signals, thereby dramatically changing the plant responses to herbivory, particularly under water stress or dark conditions. We elucidate the role of stomata, small pores on plants leaf surface, in regulating the entry of green leaf volatiles, damage-associated signals, into plants, and thus influencing their signaling functions.

ecology↗

bioRxiv2024

Insects visit Fusarium xyrophilum pseudoflowers on the host Xyris surinamensis (Xyridaceae) and carry fungal DNA on their bodies

The fungus Fusarium xyrophilum produces flower-like structures (i.e., pseudoflowers) that were recently discovered on yellow-eyed grasses (Xyris spp.) in Guyana. It is unknown whether these pseudoflowers, which are composed entirely of fungal tissue, are true mimics that attract insects as a means of fungal dispersal. We evaluated the potential of F. xyrophilum to affect insect visitation patterns to flowers and pseudoflowers by 1) documenting insect visitation to X. surinamensis in Guyana, 2) measuring the presence of F. xyrophilum DNA on insects, and 3) evaluating fluorescence and volatile production on flowers and pseudoflowers. We report for the first time Vespidae, Formicidae, Salticidae, Acrididae, and Tetrigidae visiting Xyris. Diverse insects, including Conocephalini spp. (meadow katydids; Tettigoniidae), Camponotus spp. (carpenter ants; Formicidae), and a Geometridae sp. (geometer moths) were found to visit flowers and pseudoflowers. Fusarium xyrophilum DNA was detected on 3/12 (25%) of captured insect bodies using conventional and quantitative PCR. Volatiles produced in the field by pseudoflowers and flowers were similar, except for the presence of a sesquiterpene, putatively identified here as -gurjunene, which was detected both in F. xyrophilum pure cultures and field-collected pseudoflower samples, but not from flowers. The production of this sesquiterpene by F. xyrophilum and the fluorescence of X. surinamensis peduncles represent potential signals involved in insect attraction for this system. These observations, along with the overlap in insect visitors of flowers and pseudoflowers and the detection of F. xyrophilum DNA on insect bodies, are consistent with insect visitors being vectors of Xyris pollen and F. xyrophilum propagules between host plants.

ecology↗

bioRxiv2023

The Arabidopsis thaliana carboxylesterase AtCXE12 converts volatile (Z)-3-hexenyl acetate to (Z)-3-hexenol

The green leaf volatiles (Z)-3-hexenal, (Z)-3-hexenol, and (Z)-3-hexenyl acetate are produced by nearly all plants in response to wounding and insect attack, can be transferred between plants, metabolized, and act as defense cues. If and how plant leaves convert exogenous (Z)-3-hexenyl acetate to (Z)-3-hexenol is unknown. We show that Arabidopsis leaves rapidly convert exogenous (Z)-3-hexenyl acetate to (Z)-3-hexenol. Inhibitor and fractionation experiments identified the carboxylesterases AtCXE5 and AtCXE12 as likely contributors to (Z)-3-hexenyl acetate esterase activity in Arabidopsis leaves. Heterologous expression of AtCXE5 and AtCXE12 revealed that both enzymes hydrolyze (Z)-3-hexenyl acetate to (Z)-3-hexenol in vitro, and assays using T-DNA insertion mutant plants showed that AtCXE12 significantly contributes to the conversion of (Z)-3-hexenyl acetate to (Z)-3-hexenol in planta. Lastly, we found that leaves from several other plant species possess (Z)-3-hexenyl acetate esterase activity, as well as homologs of AtCXE5 and AtCXE12 from Arabidopsis. Collectively, our study provides a better understanding of green leaf volatile biosynthesis and conversion dynamics, necessary for unraveling the potential functions of these compounds.

plant biology↗