Background: Monitoring genome size variance is essential in plant breeding for maintaining and improving plant varieties, as well as in studies of natural grasslands. There is still limited cytological data available, such as DNA quantity or ploidy level, for temperate grass species of swards.
Methods: We performed a flow cytometric genome size analysis on propidium iodide-labeled nuclei from 16 accessions of 13 perennial grass species, using pea seedlings as a control for genome size.
Results: The 2 C genome size range of the investigated perennial grass accessions was more than fivefold, ranging from 4.31 to 22.69 pg DNA per nucleus. For four accessions with known ploidy levels, our measured genome sizes matched the data reported in the referenced sources. We also estimated the ploidy level of four accessions with unknown status by comparing our genome size results with existing data. We present the previously established ploidy status along with the 2 C DNA results for Agrostis gigantea Roth and Festuca valesiaca Schleich. ex Gaudin for the first time.
Conclusions: An expanded genome size database would enable the rapid determination of the so-called DNA ploidy of taxa with unknown cytogenetic status.
Background: N6-methyladenosine (m6A), the most prevalent mRNA modification in plants, plays a pivotal role in developmental processes and stress responses. Proteins from the alpha-ketoglutarate-dependent dioxygenase (AlkB) family are implicated in the demethylation of m6A, and yet, the AlkB gene family remains poorly characterized in alfalfa.
Methods: Bioinformatic analysis was systematically performed to identify and characterize the MsAlkB gene family at the whole-genome level in alfalfa. Functional validation of MsALKBH2 was subsequently conducted using Agrobacterium rhizogenes-mediated hairy root transient transformation assays.
Results: Twenty MsALKBH candidate genes were identified from the genome of autotetraploid alfalfa cultivar Xinjiang Daye. Phylogenetic analysis classified these genes into four distinct groups, and promoter region analysis revealed numerous cis-regulatory elements associated with hormonal signaling and abiotic stress responses. With the exception of MsALKBH20, the remaining 19 MsALKBH genes were distributed across eight chromosomes. Gene duplication analyses indicated that segmental and tandem duplications were the primary drivers of the expansion of this gene family during evolution. Expression profiling of the 20 MsALKBH genes across various tissues and under salt, mannitol, and ABA treatments revealed differential expression patterns and stress-induced regulation. Real-time quantitative polymerase chain reaction analysis demonstrated that 12 MsALKBH genes were responsive to osmotic stress, with MsALKBH2 expression being notably suppressed under mannitol, salt, and ABA treatments. Overexpression of MsALKBH2 significantly reduced global m6A levels in alfalfa, mitigating oxidative damage and enhancing drought tolerance. These findings establish MsALKBH2 as an m6A demethylase that regulates drought tolerance in alfalfa.
Conclusions: This study provides the first comprehensive analysis of the MsAlkB gene family and functional characterization of MsALKBH2, offering critical insights into the potential application of this gene family for crop improvement, particularly in legume species.
Background: The endophyte Epichloë festucae var. lolii forms mutualistic symbiosis with perennial ryegrass, and their relationship under heavy metal stress needs to be more clearly defined.
Methods: This study assessed the growth and physiological response of perennial ryegrass with (E+) and without endophyte (E−) under CdCl2 (0, 50, 100, 200 mg L−1) and ZnCl2 (0, 500, 750, 1000 mg L−1) treatments.
Results: Higher concentrations of CdCl2 (200 mg L−1) and ZnCl2 (1000 mg L−1) treatments typically suppressed ryegrass growth and physiological activity, but for many traits, particularly under ZnCl2 stress, the presence of endophyte ameliorated heavy metal suppression. Specifically, E+ perennial ryegrass had significantly greater plant height, tiller number, biomass, water content, and root volume (p < 0.05) than E− perennial ryegrass under stress. Across the tested concentration ranges, a hormesis effect was observed for some ryegrass traits, and under Zn stress, the presence of endophyte enhanced the hormesis effect for malondialdehyde concentration.
Conclusions: These results indicate that Epichloë modulated growth and physiology to enhance heavy metal stress tolerance of its ryegrass host. The present study extends the understanding of how Epichloë endophyte forms a mutualistic symbiosis with perennial ryegrass.
Background: Surface-soil organic matter accumulation is expected under well-managed grasslands. Characterizing particulate and nonparticulate organic C and N fractions across a soil texture gradient under different conservation land management systems would help understand how grassland management can optimize soil organic matter to meet the challenges of environmental stress.
Methods: A cross-sectional study of 648 soil profiles sampled to 60-cm depth was conducted under a diversity of grasslands and woodlands in North Carolina, USA. Root-zone enrichments of particulate organic C and N were calculated as the difference between total and baseline stocks, derived from nonlinear depth distributions of C and N.
Results: Particulate organic C and N declined dramatically with depth, representing 35% ± 8% of total organic C at 0–10-cm depth, 14% ± 7% at 10–30-cm depth, and 10% ± 6% at 30–60-cm depth. Sand concentration had a significant negative association with both fractions. Root-zone enrichment of particulate organic C was lower under grassland than under woodland (14.2 vs. 16.7 Mg C ha−1, respectively, p < 0.001), while root-zone enrichment of particulate organic N was greater under grassland than under woodland (0.96 vs. 0.77 Mg N ha−1, respectively, p < 0.001). Root-zone enrichment of particulate organic C and N was increased by 17%–32% with poultry litter amendment and by 4%–20% in 30-year-old pastures compared with newer pastures.
Conclusions: Land use and management during the past few decades had a large influence on particulate organic C and N fractions, while pedogenic processes over millennia dominated the nonparticulate organic C and N stocks.
Grassland ecosystems are pivotal to sustaining multiple ecosystem functions and services like climate regulation, carbon sequestration, and grass production. However, the global degradation of grasslands is intensifying under the combined impacts of climate change (e.g., extreme drought) and anthropogenic activities (e.g., overgrazing). The exploration of microorganism presence and roles in degraded grasslands has achieved substantial progress. Here, we review the literature on soil microbes in degraded grasslands over the past decade, with emphasis on community response, microbial-mediated nutrient cycling processes, and potential application for restoration. Grassland degradation diminishes soil microbial diversity by reducing resource availability, resulting in the homogenization of microbial communities. However, these effects remain controversial in the context of patchy degradation. Meanwhile, degradation typically triggers the loss of key microbial species or some functional genes, coupled with suppressed activity of nutrient cycling-related enzymes, and may also promote certain processes like the decomposition of complex organic matter (e.g., lignin). We further evaluate current advances and limitations in microbial inoculant applications for grassland restoration. Some future directions in degraded grasslands are advocated, including plant–soil–microbe interaction analysis, degradation trend prediction using microbial dynamic data, and microbial multifunctional inoculant application. Promising restoration strategies, integrating metabolite identification and targeted microbiome modification, offer valuable pathways for future research and practical implementation under global change scenarios.
The purpose of this study is to draw the attention of the readers to agroforestry and more precisely to silvopastoral systems, which are land use methods with a wealth of opportunities, mixing the advantages of grasslands and forests or trees. Through an analysis of the Great Hungarian Plain in Central Europe and other large-scale restoration projects, we examine contemporary environmental challenges, with particular emphasis on water scarcity impacts on land use sustainability. We propose agroforestry systems as viable alternatives in regions where continuous forest cover cannot be sustained due to ecological limitations and where tree–crop–livestock interactions can enhance overall system productivity and resilience. The urgent need for action underlines the importance of living laboratories, where scientific work should support the overall goal of revitalizing our landscapes.
Background: This study used an online survey to explore the perspectives, practices and knowledge gaps of Irish farmers regarding the adoption of multispecies swards (MSS), a sustainable alternative to traditional monoculture grassland systems. With ruminant livestock production being central to global agricultural gross domestic product and Ireland's reliance on grass-based systems, MSS offer potential benefits for productivity, sustainability and environmental impact. However, farm-level data on MSS adoption are limited.
Methods: An adapted version of Rogers' Innovation Decision Process model was used to examine farmers' awareness, adoption drivers, perceived benefits, barriers and knowledge needs related to MSS.
Results: Among 200 Irish farmers surveyed between October 2023 and March 2024, 93% were aware of MSS and 57% had adopted it. Reported benefits included improved biodiversity, soil health, drought resilience and reduced nitrogen use, with 91% of adopters lowering fertiliser inputs. Key barriers were difficulties with establishment, grazing management, weed control and uncertainty about seed mixtures. Farmers expressed a need for more guidance on persistence and management and preferred learning via open days and discussion groups.
Conclusions: The findings highlight the need for tailored support to facilitate MSS adoption. Future initiatives should prioritise peer learning, demonstration farms and practical guidance on establishment and grazing.
The increasing global demand for livestock products (meat, milk, and wool) drives overgrazing, leading to biodiversity loss and ecosystem degradation in grasslands worldwide. Balancing production needs with ecological conservation remains a major global challenge. Drawing from the agroecological paradigms of “land sharing” and “land sparing,” we propose “grassland sharing” (dispersed grazing over expanded areas) and “grassland sparing” (concentrated grazing in restricted areas). We conducted a manipulative experiment in the typical steppe of Inner Mongolia, maintaining the same grazing intensity while contrasting spatial configurations. We hypothesize that grassland sharing enhances spatial heterogeneity, thereby promoting biodiversity, ecosystem multifunctionality, and livestock health more effectively than grassland sparing. Preliminary results indicate that grassland sharing increases livestock productivity while maintaining biodiversity, though long-term validation is still needed. This comparative study highlights the transformative potential of spatial optimization in grassland management: sharing regimes may simultaneously sustain pastoral livelihoods and ecological resilience, while sparing risks functional homogenization and reduced livestock productivity. Our findings advance evidence-based strategies to align livestock production with conservation goals, urging policymakers to integrate spatial dimensions into sustainable grassland management.