THE HIDDEN HALF: THE ROLE OF SEED-BORNE ENDOPHYTES IN VERTICAL TRANSMISSION OF DISEASE RESISTANCE AND PRIMING

Abstract

Seed-borne endophytes are a cryptic but potentially important pool of microorganisms infecting the reproductive structures of plants and vertically transmitted from generation to generation. These vertically transmitted symbionts act as a first inoculant that influences the establishment of seedlings, activates defense processes and may transmit heritable disease resistance phenotypes, as opposed to the more extensively studied rhizosphere and phyllosphere microbiomes. The aim of this review is to integrate the existing knowledge about the diversity, dynamics, and functioning of seed-borne endophytes, especially those that transmit disease resistance and systemically prime defense. The molecular dialogue between host and symbiont that controls the efficiency of transmission, the mechanisms by which seed endophytes induce resistance in the progeny plants, and the possibilities of using this knowledge in sustainable agriculture via seed biopriming strategies are discussed. Although widely recognised as important, seed endophytes have received little attention compared to other plant-associated microbiomes, and the possibility of transgenerational disease management is an unexplored realm in plant-microbe interaction studies.