The ectomycorrhizal symbiosis between Lactarius deliciosus and Pinus sylvestris in forest soil samples: symbiotic efficiency and development on roots of a rDNA internal transcribed spacer-selected isolate of L. deliciosus

Abstract

The effect on plant growth of pre-inoculation of Pinus sylvestris with the ectomycorrhizal (ECM) edible basidiomycete Lactarius deliciosus (isolate D45) under controlled conditions, and the development on roots of this basidiomycete, were investigated in gamma-irradiated and unsterilized containers containing different forest soil cores or a perlite-vermiculite mixture. Five months after planting, L. deliciosus mycorrhizal plants exhibited greater growth than the non-mycorrhizal ones in all soil types, i.e. up to a 325% increase in shoot height in the sterilized soils. The experiment demonstrated the dependency of P. sylvestris seedlings upon ECM symbiosis for their survival in gamma-irradiated, microbiologically disturbed soil samples. Furthermore, in two soils, the growth of L. deliciosus-inoculated seedlings was greater in the sterilized soil samples than in the non-sterilized ones, i.e. 46% and 132% increase in shoot height under sterilized soil conditions. In containers randomly sampled from each soil type, the degree of root colonization by the inoculated isolate, calculated as the number of mycorrhizal root tips divided by the total number of root tips x100, ranged from 80% to 35%. Within the short term, the inoculated isolate developed rapidly on roots, dominated, and hampered ectomycorrhiza formation by various unidentified (but not Lactarius) resident ECM fungi in unsterilized soil types. Results indicate that the ECM species L. deliciosus is worth investigating to ascertain if other isolates benefit pine growth like the isolate D45, and are therefore also attractive candidates for forestry applications in the Mediterranean area.

Successes and challenges in the sustainable cultivation of edible mycorrhizal fungi – furthering the dream

“…In exchange, the tree, or shrub, reallocates photosynthates to its fungal symbiont, which in most cases, are otherwise inaccessible to EMF, given their inability to decompose carbohydrate polymers such as starch, cellulose or lignin. From a practical point of view, this symbiotic relationship leads to (1) fast-growing and resilient mycorrhizal host trees ( Selosse, Bouchard, Martin, & Le Tacon, 2000 ; Guerin-Laguette, Conventi, Ruiz, Plassard, & Mousain, 2003 ; Guerin-Laguette et al, 2014 ; Garbaye, 2013 ; Arteaga-León et al, 2018 ; Wang, Guerin-Laguette, Butler, Huang, & Yu, 2019a ) and (2) an increased fungal biomass, both in the mycorrhizal roots and in soil mycelium ( Read, 1991 ; Brundrett, Bougher, Dell, Grove, & Malajczuk, 1996 ). When conditions are appropriate, usually several times a year under natural conditions, fungal biomass in the soil supports the formation of mushroom or truffle fruiting bodies.…”

Distribución, caracterización e importancia ecológica de Micromonospora en nódulos fijadores de nitrógeno de Lupinus

“…Esta simbiosis presenta un gran interés biotecnológico, ya que se ha demostrado que las plantas micorrizadas son capaces de instalarse en suelos más pobres y en condiciones más extremas, crecer más rápidamente y ser menos sensibles a las variaciones ambientales (Guerin-Laguette et al, 2003). Además, otro aspecto de gran interés en esta interacción es la formación de cuerpos fructíferos comestibles, alrededor de la cual existe un importantísimo mercado económico (Figura 1E).…”