Root metabolic plasticity underlies functional diversity in mycorrhiza‐enhanced stress tolerance in tomato

Abstract

Arbuscular mycorrhizal (AM) symbioses can improve plant tolerance to multiple stresses. We compared three AM fungi (AMF) from different genera, one of them isolated from a dry and saline environment, in terms of their ability to increase tomato tolerance to moderate or severe drought or salt stress. Plant physiological parameters and metabolic profiles were compared in order to find the molecular mechanisms underlying plant protection against stress. Mycorrhizal growth response was determined, and ultrahigh-performance LC-MS was used to compare the metabolic profile of plants under the different treatments. All AMF increased plant tolerance to stress, and the positive effects of the symbiosis were correlated with the severity of the stress. The AMF isolated from the stressful environment was the most effective in improving plant tolerance to salt stress. Differentially accumulated compounds were identified and the antistress properties of some of them were confirmed. We demonstrate that AM symbioses increase plant metabolic plasticity to cope with stress. Some responses were common to all AMF tested, while others were specifically related to particular isolates. Important metabolism reprograming was evidenced upon salt stress, and we identified metabolic pathways and compounds differentially accumulated in mycorrhizas that may underlie their enhanced tolerance to stress.

Cross‐scale integration of mycorrhizal function

“…Rivero et al . (; in this issue of New Phytologist , pp. 1322–1336) examine plant metabolic plasticity in stressed tomato plants, and note that AM symbioses can help plants deal with this stress, and the Tansley insight by Sawers et al .…”

Phytobiome metabolism: beneficial soil microbes steer crop plants' secondary metabolism

“…AMF inoculations boost plant health and production in adverse environmental conditions. Besides phenotypic plasticity, AMF induce global metabolic changes in plants, however, effects are AMF strain and plant specific . Plants belonging to the Plantaginaceae, Fabaceae, and Poaceae families inoculated with Rhizophagus irregularis possessed increased foliar phosphorus content and displayed changes in the leaf metabolome .…”

“…Moreover, the same AMF strain induced high accumulation of steroidal glycoalkaloids (SGAs; e.g. tomatidine) in tomato plants challenged with salt stress . Although SGAs are not frequently associated with abiotic stress responses, these compounds are known for their antimicrobial and insecticidal activities .…”

“…tomatidine) in tomato plants challenged with salt stress. 50 Although SGAs are not frequently associated with abiotic stress responses, these compounds are known for their antimicrobial 74 and insecticidal activities. 75 For instance, under abiotic stress, C. etunicatum inoculated tomato were less prone to damage from pests and pathogens than non-inoculated plants.…”

EXOTIC ARBUSCULAR MYCORRHIZAL FUNGI AND NATIVE DARK SEPTATE ENDOPHYTES ON THE INITIAL GROWTH OF Paspalum millegrana GRASS

“…In return, the host plants provide the symbiotic fungus with photoassimilates for nutrition. By these interactions, the AMF promotes plant growth (SANTOS et al, 2018a); induces the defense system against pathogens and/or pests (VOLPE et al, 2018;HEIDJEN et al, 2015); increases the absorption of water and nutrients and reduce the consumption of mineral fertilizers (ZIANE et al, 2017); reducing nitrogen and phosphorus losses in the soil (TEUTSCHEROVA et al, 2019;OKONJI et al, 2018), and promoting tolerance to drought and salinity (RIVERO et al, 2018). However, the beneficial effects of AMF symbiosis on the host plant are not restricted to plant growth.…”