Natural fumigation as a mechanism for volatile transport between flower organs

TL;DR

This study uncovers a novel natural fumigation process in plants where VOCs are transported between organs, influencing development and defense, with potential implications for plant reproduction and pollination timing.

Contribution

It reveals a new physiological mechanism of inter-organ VOC transport via natural fumigation, expanding understanding of plant chemical communication and defense.

Findings

VOCs are transported from buds to stigma before flower opening.

Terpene synthase activity produces sesquiterpenes inside buds.

VOCs influence stigma defense, development, and seed yield.

Abstract

Plants synthesize volatile organic compounds (VOCs) to attract pollinators and beneficial microorganisms, to defend themselves against herbivores and pathogens and for plant-plant communication. Generally, accumulation and emission of VOCs occur from the tissue of their biosynthesis. However, using biochemical and reverse genetic approaches, we demonstrate a new physiological phenomenon: inter-organ aerial transport of VOCs via natural fumigation. Before petunia flowers open, a tube-specific terpene synthase produces sesquiterpenes, which are released inside the buds and then accumulate in the stigma, potentially defending the developing stigma from pathogens. These VOCs also affect reproductive organ development and seed yield, which is a previously unknown function for terpenoid compounds. could serve as a mechanism to coordinate the timing of pistil development with petal development in order to insure that the stigma is receptive when the flowers are most likely to attract pollinators. Further studies are required to assess whether natural fumigation is conserved in flowering plants, to uncover the mechanisms involved, and to determine its evolutionary advantage in plant reproduction.