Proteomic Insight into the Symbiotic Relationship of Pinus massoniana Lamb and Suillus luteus towards Developing Al-Stress Resistance

Abstract

Global warming significantly impacts forest range areas by increasing soil acidification or aluminum toxicity. Aluminum (Al) toxicity retards plant growth by inhibiting the root development process, hindering water uptake, and limiting the bioavailability of other essential micronutrients. Pinus massoniana (masson pine), globally recognized as a reforestation plant, is resistant to stress conditions including biotic and abiotic stresses. This resistance is linked to the symbiotic relationship with diverse ectomycorrhizal fungal species. In the present study, we investigated the genetic regulators as expressed proteins, conferring a symbiotic relationship between Al-stress resistance and Suillus luteus in masson pine. Multi-treatment trials resulted in the identification of 12 core Al-stress responsive proteins conserved between Al stress conditions with or without S. luteus inoculation. These proteins are involved in chaperonin CPN60-2, protein refolding and ATP-binding, Cu-Zn-superoxide dismutase precursor, oxidation-reduction process, and metal ion binding, phosphoglycerate kinase 1, glycolytic process, and metabolic process. Furthermore, 198 Al responsive proteins were identified specifically under S. luteus-inoculation and are involved in gene regulation, metabolic process, oxidation-reduction process, hydrolase activity, and peptide activity. Chlorophyll a-b binding protein, endoglucanase, putative spermidine synthase, NADH dehydrogenase, and glutathione-S-transferase were found with a significant positive expression under a combined Al and S. luteus treatment, further supported by the up-regulation of their corresponding genes. This study provides a theoretical foundation for exploiting the regulatory role of ectomycorrhizal inoculation and associated genetic changes in resistance against Al stress in masson pine.

Inter- and intra-specific metal tolerance variation in ectomycorrhizal fungal Suillus species

“…Similarly, metal tolerant S. luteus can prevent the accumulation of Zn in P. sylvestris roots (Zhang et al 2021) and improve pine growth under Cd stress, with Cd-tolerant isolates signi cantly improving pine nutrient uptake and reducing Cd needle content in high Cd concentrations (Krznaric et al 2009). Similar trends have been found in S. luteus from Asia, that reduces the toxic effects of high soil aluminum concentrations for pine partners (Liu et al 2021). These effects make metal tolerant Suillus isolates good candidates for assisting in recovering degraded sites, for example by priming seedlings for transplantation into metal contaminated soils (Branco et al 2022).…”

Ectomycorrhizal Inoculation Enhances the Salt Tolerance of Quercus mongolica Seedlings

“…Previous studies have shown that most of the ectomycorrhizal symbioses species of C. mollissima belong to Basidiomycota [ 25 ], which includes G. viscidus and S. luteus . S. luteus has a wide distribution and has been studied in many Pinaceae plants [ 26 , 27 , 28 ]; less research has been conducted on G. viscidus . However, neither of these two types of ectomycorrhizal fungi have been thoroughly studied in Quercus .…”

Suillus: an emerging model for the study of ectomycorrhizal ecology and evolution

“…For example, Adriaensen et al (2005) demonstrated that inoculation with Cu-tolerant isolates of S. luteus significantly improved plant phosphorus and nitrogen uptake in Cu-contaminated soil, while Cu-sensitive isolates reduced nutrient uptake and transfer. Suillus colonization can also facilitate metal tolerance indirectly, for example, Liu et al (2020Liu et al ( , 2021) demonstrated that S. luteus activates multiple plant stress pathways, enhancing plant fitness during metal exposure. Similarly, metal exclusion mechanisms in tolerant Suillus isolates have been shown to reduce metal transfer to the host (Krupa & Kozdr oj, 2004;Zhang et al, 2021).…”

“…Suillus colonization can also facilitate metal tolerance indirectly, for example, Liu et al . (2020, 2021) demonstrated that S. luteus activates multiple plant stress pathways, enhancing plant fitness during metal exposure. Similarly, metal exclusion mechanisms in tolerant Suillus isolates have been shown to reduce metal transfer to the host (Krupa & Kozdrój, 2004; Zhang et al ., 2021).…”