Plant defense signaling from the underground primes aboveground defenses to confer enhanced resistance in a cost-efficient manner

Abstract

Plants can be induced to develop below- and aboveground enhanced resistance to pathogens and herbivorous insects by root-colonizing beneficial micro-organisms. The resistance induced is broad-spectrum and can be long-lasting. The enhanced resistance is based at least partially on priming of defense responses, leading to a more rapid or more intense mobilization of defense responses upon encounter with harmful organisms. Several molecular players in local and systemic tissues of plants treated with resistance-inducing microbes have been identified and will be reviewed here. We also will discuss the ecological consequences of expression of induced resistance through a primed defense response.