Ectomycorrhizal and Dark Septate Fungal Associations of Pinyon Pine Are Differentially Affected by Experimental Drought and Warming

Abstract

Changing climates can cause shifts in temperature and precipitation, resulting in warming and drought in some regions. Although each of these factors has been shown to detrimentally affect forest ecosystems worldwide, information on the impacts of the combined effects of warming and drought is lacking. Forest trees rely on mutualistic root-associated fungi that contribute significantly to plant health and protection against climate stresses. We used a six-year, ecosystem-scale temperature and precipitation manipulation experiment targeted to simulate the climate in 2100 in the Southwestern United States to quantify the effects of drought, warming and combined drought and warming on the root colonization (abundance), species composition and diversity of ectomycorrhizal fungi (EMF), and dark septate fungal endophytes in a widespread woodland tree, pinyon pine (Pinus edulis E.). Our results show that pinyon shoot growth after 6 years of these treatments was reduced more by drought than warming. The combined drought and warming treatment reduced the abundance and diversity of EMF more than either treatment alone. Individual ectomycorrhizal fungal taxa, including the drought tolerant Cenococcum geophilum, were present in all treatments but the combined drought and warming treatment. The combined drought and warming treatment also reduced the abundance of dark septate endophytes (DSE), but did not affect their diversity or species composition. The current year shoot growth of the trees correlated positively with ectomycorrhizal fungal diversity, highlighting the importance of diversity in mutualistic relationships to plant growth. Our results suggest that EMF may be more important than DSE to aboveground growth in P. edulis, but also more susceptible to the negative effects of combined climate stressors.

Lower relative abundance of ectomycorrhizal fungi under a warmer and drier climate is linked to enhanced soil organic matter decomposition

“…Our inferences about changes in EMF and saprotrophic fungal abundance are based on relative abundances calculated from sequence read counts, which is similar to the approach used in other studies (Sterkenburg et al ., 2018). Despite the semiquantitative nature of this approach (Amend et al ., 2010), the data unequivocally revealed a drastic decrease in raw and relative EMF sequence abundance under simulated warmer and drier conditions, which is similar to the findings of another two independent climate change experiments from dryland ecosystems (León‐Sánchez et al ., 2018; Gehring et al ., 2020). This result is also in agreement with the trend of decreasing EMF abundance encountered along aridity gradients in global drylands (Berdugo et al ., 2020).…”

Land‐use history alters the diversity, community composition and interaction networks of ectomycorrhizal fungi in beech forests

“…Accordingly, this species was more abundant in long-established forests since these have lower soil water holding capacity than recent forests used for pastureland (Grove & Rackham, 2003). The mycorrhizal association with C. geophilum might confer beech a higher resistance to drought (Gehring et al, 2020), a relevant trait for surviving in this southern location that deserves further investigation.…”

“…Accordingly, this species was more abundant in long-established forests since these have lower soil water holding capacity than recent forests used for pastureland (Grove & Rackham, 2003). The mycorrhizal association with C. geophilum might confer beech a higher resistance to drought (Gehring et al, 2020) understanding the recovery of this mutualism will be to quantify the intensity of the interaction in both forest types by estimating how much nitrogen is absorbed by the plant due to each species of ECM fungus (Pena et al, 2013) and how much carbon is absorbed by each species of fungus (Neufeld et al, 2007). The forest expansion that Europe has been experiencing due to the widespread abandonment of rural landscapes in the last century has created new forests that can contribute to carbon sequestration (Bonan, 2008;Vilà-Cabrera et al, 2016) and provide other ecosystem services (i.e.…”

“…The mycorrhizal association with C . geophilum might confer beech a higher resistance to drought (Gehring et al., 2020), a relevant trait for surviving in this southern location that deserves further investigation.…”

Ectomycorrhizal Fungi Associated with Pinus densiflora Seedlings under Flooding Stress

“…In addition to assisting with the acquisition of essential nutrients and water, EMF allow plants to tolerate various detrimental environmental factors, such as droughts, flooding, and high heavy metal, salt, and organic pollutant concentrations [2][3][4][5][6][7]. The effects of EMF on plants under the context of climate change have recently been highlighted, and many studies have focused on characterizing the EMF-plant response to droughts [8][9][10]. However, little research has been conducted on EMF under flooding stress.…”