Unraveling the Dark Septate Endophyte Functions: Insights from the Arabidopsis Model

Abstract

The global occurrence of plant root-associated fungal endophytes and their great abundance in many habitats necessitate studies to decipher their potential functions. Improved understanding of the basic endophyte ecology including host range, host preference, and host responses to endophyte colonization has been made possible through populations of endophytes (e.g., Periconia macrospinosa and Microdochium sp.) isolated from North American native tallgrass prairie. The recent demonstration of the endophyte symbiosis of the model plant Arabidopsis thaliana has provided additional tools to further elucidate the ecology of these endophytes. The availability of a large number of Arabidopsis ecotypes and mutants, microarrays, and databases allows the molecular dissection of endophyte symbiosis to better understand the importance of fungal endophytes in host nutrient uptake, defenses, and/or responses to pathogens and stress. In this chapter, we discuss the ecology and functions of endophytic fungi through experiments utilizing the Arabidopsis model system. We draw parallels with another deeply dissected Piriformospora indica root endophyte symbiosis, which has been demonstrated to promote growth of model and non-model plants.

Growth promotion mediated by endophytic fungi in cloned seedlings of Eucalyptus grandis x Eucalyptus urophylla hybrids

“…It has been suggested that endophytic fungi can act symbiotically with plants, increasing the absorption of nutrients as well as the response to pathogens and stress conditions, which translates into gains in growth (Mandyam and Jumpponen, 2014). In this study, a linear temporal increase was observed for SL in all treatments.…”

Indoleacetic acid production and plant growth promoting potential of bacterial endophytes isolated from rice (Oryza sativa L.) seeds

“…Such endophytic bacteria colonize healthy plant tissues without causing any disease symptoms to the host plants. Endophytes have been regarded as the most prolific class of microorganisms that can help host plants to counteract the negative impacts of biotic and abiotic stress conditions [5,24]. Endophytic bacteria can be an alternative to chemical fertilizers as the use of bacterial endophytes has been practiced throughout the world to replace the use of chemical fertilizer [26].…”

Fungal colonization of plant roots is resistant to nitrogen addition and resilient to dominant species losses

“…A wide variety of biotic and abiotic drivers regulate the colonization rates of root fungal symbionts. For instance, root colonization rates by AMF and DSE differ among plant functional groups, with grasses in this montane ecosystem commonly supporting higher colonization of DSE relative to AMF, whereas forbs are typically more heavily colonized by AMF (Newsham , Mandyam and Jumpponen , Ranelli et al. ).…”

“…A wide variety of biotic and abiotic drivers regulate the colonization rates of root fungal symbionts. For instance, root colonization rates by AMF and DSE differ among plant functional groups, with grasses in this montane ecosystem commonly supporting higher colonization of DSE relative to AMF, whereas forbs are typically more heavily colonized by AMF (Newsham 2011, Mandyam and Jumpponen 2014, Ranelli et al 2015. Additionally, plant nutrient status and soil nutrient availability are strong determinates of fungal colonization rates (Bruce et al 1994, Johnson et al 2003, Egerton-Warburton et al 2007, Henning et al 2018.…”