Arbuscular mycorrhizal fungi (AMF) have established themselves as pivotal allies in the realm of plant physiology, renowned for their remarkable contributions to augmenting both growth and resilience against environmental stresses. In this study, we embarked on a comprehensive investigation into the discernible impact of two distinct AMF species on a widely planted oat cultivar, ‘Qingyan No. 1’, when subjected to the austere conditions of a drought. The experimental design included three distinct AMF treatments (inoculation with Rhiaophagus intraradices, Funneliformis mosseae, or not), and the three water treatments were 75% of field capacity (well watered), 50% of field capacity (moderate drought), and 30% of field capacity (severe drought). The obtained results showed that the rate of inoculation under 75% FC for both AMF species was over 74%. Drought stress limited the growth and osmotic regulation of the oat plants. However, AMF inoculation observably increased the above-ground biomass under 75% FC and increased the root biomass under 30% FC. AMF inoculation also increased the root traits under 75% FC and 50% FC. R. intraradices inoculation increased the above-ground soluble sugar and soluble protein concentrations, and both AMF species showed decreased malondialdehyde (MDA) concentrations in the roots. Furthermore, the pervasive influence of drought stress exerted a discernible stranglehold on nutrient uptake in the oat plants, profoundly impacting the distribution of nutrients within the shoots and roots. Regardless of the drought stress treatment, the inoculation with both AMF species increased the P concentrations in the roots and the K and Mg concentrations in the roots, and the inoculation with R. intraradices increased the Ca concentration in the whole oat plant. Under 75% FC, the N concentration of the whole oat plant was significantly reduced by both AMF species. However, under 50% FC and 30% FC, the N concentrations in the shoots inoculated with both AMF species were close to that of the non-inoculated shoots. In summary, AMF improved the osmotic regulation and nutrient absorption and distribution of oat plants under drought stress and thus promoted the growth and biomass accumulation of oat plants.

The alpine forage grass species Elymus nutans Griseb. is widely distributed in the Qinghai–Tibet Plateau and the Himalayas due to its high adaptability. However, it has become threatened by climate warming and excessive grazing. Thus, understanding its genetic and phenotypic information is crucial to aid resource management and conservation efforts. In this study, microsatellite markers were developed based on RNA-seq transcriptome data from E. nutans Griseb. varieties ‘Aba’ and ‘Kangbei’, resulting in the identification of 48,457 SSRs from 304,554 de novo assembled unigenes. Seventeen polymorphic markers, 13 inflorescence phenotypic traits, and seed shattering values were determined for 31 E. nutans accessions collected from eastern Tibet. The molecular markers generated 134 well-amplified bands with a mean Nei’s genetic diversity of 0.31 and a Shannon information index of 0.46. Pairwise genetic similarity ranged from 0.554 to 0.895, with an average of 0.729. Based on the molecular marker data, all accessions were divided into two classes via the unweighted pair-group method with arithmetic mean (UPGMA), the Markov chain Monte Carlo method, and the principal coordinate analysis (PCA) method. We used Tassel analysis to determine 11 loci with a significant relationship to phenotypic traits, and Pearson’s correlation analysis showed that some inflorescence traits were significantly influenced by the environment. Furthermore, we detected strong patterns of isolation by both environment (IBE) and distance (IBD) via Mantel analysis. This study provides valuable insights into the genetic and phenotypic differentiation of E. nutans, informing germplasm resource evaluation and future breeding.