Differential Strategies of Ectomycorrhizal Development between Suillus luteus and Pinus massoniana in Response to Nutrient Changes

Ectomycorrhizal fungi employ different strategies for mycelial growth and host colonization under varying nutrient conditions. However, key genes associated with mycorrhizal interaction should be influenced solely by the inoculation treatment and not by nutrient variations. To utilize subtle nutrient differences and rapidly screen for key genes related to the interaction between <i>Suillus luteus</i> and <i>Pinus massoniana</i>, we performed an inoculation experiment using culture bottles containing high- and low-nutrient media. Interestingly, <i>S. luteus</i> LS88 promoted the growth of <i>P. massoniana</i> seedlings without mature ectomycorrhiza, and the impact of LS88 inoculation on <i>P. massoniana</i> roots was greater than that of nutrient changes. In this study, the resequenced genome of the LS88 strain was utilized for transcriptome analysis of the strain. The analysis indicated that a unique gene encoding glutathione S-transferase (GST) in LS88 is likely involved in colonizing <i>P. massoniana</i> roots. In this study, the GST gene expression was independent of nutrient levels. It was probably induced by <i>P. massoniana</i> and could be used as a marker for <i>S. luteus</i> colonization degree.