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The GRAS protein family is involved in plant growth and development, plant disease resistance, and abiotic stress response. Although the GRAS protein family has been systematically studied and reported in many plants, it has not been reported in oat, an excellent foodstuff crop of Gramineae. We identified 90 AsGRAS genes and all of the AsGRAS genes were randomly distributed on 21 chromosomes with 6 tandem duplicated genes and 49 pairs of segmental duplications, which may be the main reason for the expansion of the GRAS gene family. According to the phylogenetic tree, 90 AsGRASs were classified into 10 distinct subfamilies. Gene structure revealed introns varying from zero to seven, and all genes have conserved motifs and GRAS structure domain. Protein–protein interaction and miRNA prediction analysis showed that AsGRAS proteins mainly interacted with GA signalling, cell division, etc., and that the AsGRAS genes were targeted by miRNA171. RNA-seq and qRT–PCR data showed that GRAS genes were expressed at different growth and developmental stages and under different abiotic stresses in oat, indicating the potential role of GRAS genes in promoting growth and stress tolerance in oat. Overall, our evolutionary and expression analysis of AsGRAS genes contributes to the elucidation of a theoretical basis for the GRAS gene family. Moreover, it helped reveal gene function and laid the foundation for future agricultural improvement of oats based on functional properties. [ABSTRACT FROM AUTHOR]

Although nitrogen (N) and phosphorus (P) fertilization are important for maintaining the health and productivity of Leymus chinensis steppe, their impact on the abundance and community structure of ammonia-oxidizing bacteria (AOB) and ammonia-oxidizing archaea (AOA) in this ecosystem is still unclear. We used the amoA gene as a molecular marker to monitor changes in AOA and AOB under low and high N and P fertilization and applied the resin-core technique to measure soil N mineralization. We found that the abundance of AOA based on amoA gene copies, ranging from 7.51 × 107 to 1.23 × 108 copies g−1 soil, was higher than that of AOB. Fertilization, especially high N and P, increased the number of amoA copies associated with AOB. AOA and AOB communities were dominated by Crenarchaeota and Proteobacteria, respectively. Fertilization decreased the relative abundances of Thaumarchaeota in the AOA community and Proteobacteria in the AOB community and increased the relative abundance of Ammonia_oxidizing_bacteria_ensemble. In N and P fertilization treatments, soil N transformation was closely related to AOB but not AOA. Soil ammonium N and nitrate N reshape the structure of ammonia oxidizers of AOB but not those of AOA on L. chinensis steppes. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The seed yield of grass species is greatly dependent on inflorescence morphological traits, starting with spikelets per inflorescence and seeds per spikelet, to kernel size, and then to awns. Previous studies have attempted to estimate the contribution of these traits on the harvested yield of major cereal crops, but little information can be accessed on the influence of awns on seed yield of forage grass species. Siberian wildrye (Elymus sibiricus L.) is a widely important perennial forage grass used to increase forage production in arid and semi-arid grasslands. The grass has long inflorescences with long awns developed at the tip end of the lemmas in the florets. In order to evaluate the effect of awns on Siberian wildrye seed production, awn excision analyses from 10 accessions were performed at flowering stage under irrigated and rainfed regimes. Overall, awn excision reduced thousand-seed weight and seed size under both irrigated and rainfed regimes, which decreased final seed yield per plant. De-awned plants produced significantly more seeds per inflorescence, but spikelets per inflorescence was not influenced by awn excision in either condition. Moreover, histological analyses showed a high degradation of the abscission layer in the awned plants than de-awned ones, and awn excision evidently improved average seed breaking tensile strength (BTS), and thus decreased the degree of seed shattering. In conclusion, the observed significant impact of awn excision on different yield-related traits mirrored the impact of awns on the performance of Siberian wildrye under diverse growing conditions. These results provide useful information for plant breeders, seed producers, and researchers to efficiently improve seed production in Siberian wildrye. [ABSTRACT FROM AUTHOR]

Alkaloids produced by endophytic fungi can have an important influence on agricultural ecology, and can often be affected by climatic factors. At present, there are no studies that have assessed the relationship between alkaloid production and elevation or climatic factors in the Qinghai-Tibetan Plateau. To address this knowledge gap, we explored ergot alkaloid and peramine production in Epichloë-infected (E+) Elymus tangutorum collected from the Qinghai-Tibetan plateau and assessed the relationship between the concentration of these alkaloids and elevation. The effects of temperature and precipitation on these relationships were also investigated. The concentrations of ergonovine, ergine, and peramine ranged from 0.47–0.84, 0.35–1.72 and 9.18–13.00 µg·g−1, respectively. Fitted cubic regression curves describing an arc-pattern across the elevational series were statistically significant for ergine and peramine concentrations. The elevational trend in peramine concentration was linked to mean daily temperature, while the ergine elevational trend was linked to mean precipitation. Our results provide a new understanding of the climatic factors that influence the alkaloid production of endophytic fungi at different elevations in the Qinghai-Tibetan plateau. [ABSTRACT FROM AUTHOR]