Transcriptome Analysis Provides Novel Insights into the Capacity of the Ectomycorrhizal Fungus Amanita pantherina To Weather K-Containing Feldspar and Apatite.

Ectomycorrhizal (ECM) fungi, symbiotically associated with woody plants, markedly improve the uptake of mineral nutrients such as potassium (K) and phosphorus (P) by their host trees. Although it is well known that ECM fungi can obtain K and P from soil minerals through biological weathering, the mechanisms regulating this process are still poorly understood at the molecular level. Here, we investigated the transcriptional regulation of the ECM fungus Amanita pantherina in weathering K-containing feldspar and apatite using transcriptome sequencing (RNA-seq) and validated these results for differentially expressed genes using real-time quantitative PCR. The results showed that A. pantherina was able to improve relevant metabolic processes, such as promoting the biosynthesis of unsaturated fatty acids and steroids in the weathering of K-containing feldspar and apatite. The expression of genes encoding ion transporters was markedly enhanced during exposure to solid K-containing feldspar and apatite, and transcripts of the high-affinity K transporter ApHAK1, belonging to the HAK family, were significantly upregulated. The results also demonstrated that there was no upregulation of organic acid biosynthesis, reflecting the weak weathering capacity of the A. pantherina isolate used in this study, especially its inability to utilize P in apatite. Our findings suggest that under natural conditions in forests, some ECM fungi with low weathering potential of their own may instead enhance the uptake of mineral nutrients using their high-affinity ion transporter systems.IMPORTANCE In this study, we revealed the molecular mechanism and possible strategies of A. pantherina with weak weathering potential in the uptake of insoluble mineral nutrients by using transcriptome sequencing (RNA-seq) technology and found that ApHAK1, a K transporter gene of this fungus, plays a very important role in the acquisition of K and P. Ectomycorrhizal (ECM) fungi play critical roles in the uptake of woody plant nutrients in forests that are usually characterized by nutrient limitation and in maintaining the stability of forest ecosystems. However, the regulatory mechanisms of ECM fungi in acquiring nutrients from minerals/rocks are poorly understood. This study investigated the transcriptional regulation of A. pantherina weathering K-containing feldspar and apatite and improves the understanding of fungal-plant interactions in promoting plant nutrition enabling increased productivity in sustainable forestry.

Sun Q ，Fu Z ，Finlay R ，Lian B ... -  《-》

Plant-driven weathering of apatite--the role of an ectomycorrhizal fungus.

Smits MM ，Bonneville S ，Benning LG ，Banwart SA ，Leake JR ... -  《-》

Effects of mineral substrate on ectomycorrhizal fungal colonization and bacterial community structure.

Ectomycorrhizal (ECM) fungi can promote the nutrient uptake of plants from soil minerals by bioweathering. However, effects of different minerals on ECM fungal colonization and bacterial community structures in the soil remains poorly documented. Here, we investigated ECM fungal composition and bacterial communities in different mineral-filled mesh bags buried in forest soil. Control (filled with quartz, which has little nutrients for plants) and mineral (apatite, potash feldspar and serpentine) -filled mesh bags were buried in E-horizon soil for six months. After incubation, the contents of available elements in bags were determined, bacterial population sizes were quantified by quantitative PCR, and bacterial and ECM fungal community structures in mesh bags were assessed using high-throughput sequencing. The results showed that dozens of ECM fungal species colonized in different mesh bags, of which 17, 54 and 47 ECM species were observed in apatite-, potash feldspar- and serpentine-filled bags, respectively. Ectomycorrhizal fungal composition and bacterial community structure are affected significantly by mineral types. Pseudomonas, Sphingomonas, Bacillus and Paenibacillus, known for high weathering potential, were the preponderant bacteria in mineral-filled bags compared to the control. Ectomycorrhizal fungi are able to selectively colonize mesh bags based on mineral types, and may have a certain influence on the formation of bacterial community structure, implying a possible cooperation of ECM fungi and bacteria in soil mineral weathering.

Sun Q ，Liu X ，Wang S ，Lian B ... -  《-》

Ectomycorrhizal weathering of the soil minerals muscovite and hornblende.

van Schöll L ，Smits MM ，Hoffland E 《NEW PHYTOLOGIST》

Molecular and functional characterization of a Na(+)-K(+) transporter from the Trk family in the ectomycorrhizal fungus Hebeloma cylindrosporum.

Corratgé C ，Zimmermann S ，Lambilliotte R ，Plassard C ，Marmeisse R ，Thibaud JB ，Lacombe B ，Sentenac H ... -  《JOURNAL OF BIOLOGICAL CHEMISTRY》