A fungal endophyte strategy for mitigating the effect of salt and drought stress on plant growth

Functional roles of microbial symbionts in plant cold tolerance

“…Despite the recent recognition of the beneficial effects of endophytic microbes on plant survival (Saikkonen et al 1998; Porras‐Alfaro & Bayman 2011; Rho & Kim 2017), there is now mounting evidence that fungal and bacterial symbionts exert similar effects on a range of plant species by triggering diverse metabolic and physiological processes, particularly under adverse environmental conditions (Porras‐Alfaro & Bayman 2011; Gundel et al 2013; Dighton & White 2017; van Bael et al 2017; Hill et al 2019). These beneficial effects, which are strongly dependent on environmental conditions (Saikkonen et al 1998; Rodriguez et al 2009), encompass osmotic regulation (Azad & Kaminskyj 2016; Molina‐Montenegro et al 2016), plasticity (Goh et al 2013), reproduction (Saikkonen et al 2004), priming against pests or herbivores (Gonzáles‐Teuber 2016) and the acquisition of growth‐limiting nutrients from soil (Upson et al 2009a; Newsham 2011; Rho et al 2018; Hill et al 2019).…”

“…In some cases, the same compound is used in more than one stress response pathway (Saikkonen et al 2013), and it is hence not surprising that the positive effects of microbial symbionts on plant performance encompass a wide range of processes such as germination, establishment, defense and/or survival (Pineda et al 2013; Schoenrock et al 2013; Hardoim et al 2015; Khan et al 2015; Busby et al 2016). However, just as microbial symbionts are thought to influence plant responses to nutrient limitation and osmotic stress (Newsham 2011; Molina‐Montenegro et al 2016; Azad & Kaminskyj 2016), it is becoming increasingly apparent that the cold stress responses of plants may be influenced by their interactions with microbes (Tibbett & Cairney 2007; Tiryaki et al 2019).…”

A novel experimental system using the liverwort Marchantia polymorpha and its fungal endophytes reveals diverse and context‐dependent effects

“…Endophytes can be anywhere on the spectrum from mutualist to pathogen, as long as they have at least a brief asymptomatic phase of colonization (Schulz & Boyle, 2005;Porras-Alfaro & Bayman, 2011). These fungi can affect hosts in many ways, including changing plant metabolite production (Prasad et al, 2013;Aschehoug et al, 2014); nutrient use (Yang et al, 2014); and resistance to pathogens (Arnold et al, 2003;Tellenbach & Sieber, 2012), herbivores, (Jaber & Vidal, 2010;Gange et al, 2012) or abiotic stress (Murphy et al, 2015;Azad & Kaminskyj, 2016;Molina-Montenegro et al, 2016;Yamaji et al, 2016;Khan et al, 2017). Plant-endophyte interactions are dynamic, with the outcomes depending on timing, dosage, environmental conditions, and complex signaling between partners (Johnson et al, 1997;McCormick et al, 2001;Partida-Martinez & Heil, 2011;Hiruma et al, 2016;Swett & Gordon, 2017).…”

Metabolic responses of endophytic Nicotiana benthamiana plants experiencing water stress

“…Although the role of fungal endophytes to mediate plant water stress tolerance has been described in several studies, the key mechanism(s) are incompletely understood. Endophyte colonization causes (a) increased growth and development (Khan et al, 2013;Redman et al, 2011) (b) enhanced osmotic adjustment (Grover et al, 2001), (c) increased gas exchange and water use efficiency (Bae et al, 2009;Elmi and West, 1995) and (d) improved defence against oxidative stress in host plants (Azad and Kaminskyj, 2016). Metabolomic studies in Festuca arundinacea (tall fescue) colonised with E. coenophiala have reported a significant impact of the endophyte, on primary and secondary metabolism under water deficit conditions (Nagabhyru et al, 2013;Rasmussen et al, 2008).…”