The Role of the Endophytic Microbiome in the Grapevine Response to Environmental Triggers

Abstract

Endophytism within Vitis represents a topic of critical relevance due to the multiple standpoints from which it can be approached and considered. From the biological and botanical perspectives, the interaction between microorganisms and perennial woody plants falls within the category of stable relationships from which the plants can benefit in multiple ways. The life cycle of the host ensures persistence in all seasons, repeated chances of contact, and consequent microbiota accumulation over time, leading to potentially high diversity compared with that of herbaceous short-lived plants. Furthermore, grapevines are agriculturally exploited, highly selected germplasms where a profound man-driven footprint has indirectly and unconsciously shaped the inner microbiota through centuries of cultivation and breeding. Moreover, since endophyte metabolism can contribute to that of the plant host and its fruits’ biochemical composition, the nature of grapevine endophytic taxa identities, ecological attitudes, potential toxicity, and clinical relevance are aspects worthy of a thorough investigation. Can endophytic taxa efficiently defend grapevines by acting against pests or confer enough fitness to the plants to endure attacks? What are the underlying mechanisms that translate into this or other advantages in the hosting plant? Can endophytes partially redirect plant metabolism, and to what extent do they act by releasing active products? Is the inner microbial colonization necessary priming for a cascade of actions? Are there defined environmental conditions that can trigger the unleashing of key microbial phenotypes? What is the environmental role in providing the ground biodiversity by which the plant can recruit microsymbionts? How much and by what practices and strategies can these symbioses be managed, applied, and directed to achieve the goal of a better sustainable viticulture? By thoroughly reviewing the available literature in the field and critically examining the data and perspectives, the above issues are discussed.

Relevant responses in grape cells exposed to endophytic fungi or to fungal extracts at transcriptome and metabolome scopes

“…Endophytes have been greatly concerned due to their bene cial interactions with host plants, such as growth promoting, stress adaptability, biochemistry shaping and others [1,2]. And these hyperdiverse communities of endophytes provided tremendous resources for crop managements as multiple standpoint.…”

“…And these hyperdiverse communities of endophytes provided tremendous resources for crop managements as multiple standpoint. This will great interest to those crops given organoleptic sensitive products, such as grapevines, in which a ne-turned metabolic changes might trigger obvious quality and characteristic effects on the resultant wine [2,6]. Researches have covered the metabolic impacts of pure cultured fungal endophytes on grape cells under well controlled conditions in dual cultures, which appeared fungal strain, species and other taxonomical speci cities in shaping the metabolites of grape cells [7,9,10].…”

“…Endophyte was de ned as all microorganisms colonize internal plant tissues for all or part of their lifetime [1]. The groups of endophytes within host plants represents a hot topic of great relevance due to the multiple standpoints from which it can be approached and considered [2]. Functions of endophytes to host plants ranged from mutualistic to pathogenic, with most of them in plant may appear neutral effects or no function at all to their hosts, namely "commensal" [1].…”

“…Functions of endophytes to host plants ranged from mutualistic to pathogenic, with most of them in plant may appear neutral effects or no function at all to their hosts, namely "commensal" [1]. Even though, the bene cial interactions of endophytes with their hosts still attracted great attentions for their possible utilization in crop quality managements, especially to those perennial woody crops such as grapevines, which the hosts could receive long term effects [2]. Several endophytes with positive functions such as adapt to abiotic stresses, defense against pathogens, growth promotion and plant quality improvements on grapevines have been revealed and developed [2].…”

“…Even though, the bene cial interactions of endophytes with their hosts still attracted great attentions for their possible utilization in crop quality managements, especially to those perennial woody crops such as grapevines, which the hosts could receive long term effects [2]. Several endophytes with positive functions such as adapt to abiotic stresses, defense against pathogens, growth promotion and plant quality improvements on grapevines have been revealed and developed [2]. These endophytes as bacterial endophyte Paraburkholderia phyto rmans strain PsJN has been observed to be conducive as a chilling stress-preventive trait as plants bearing this endophyte [3,4].…”