Cadmium (Cd) poses a threat to plant growth. Nitrogen (N) has been demonstrated to alleviate Cd phytotoxicity, but the underlying mechanism in woody plants remains unclear. In this study, we aimed to determine whether exogenous NH₄HCO₃ influences rhizosphere soil properties and fungal communities, thereby enhancing plant growth and Cd phytoaccumulation in Populus yunnanensis Dode. A pot experiment was conducted in a greenhouse, with seedlings subjected to four treatments: CK (no additional N and Cd), N (24 mg N kg-1 month-1 supplied as NH₄HCO₃), Cd (20 mg Cd kg-1 month-1), and CN (24 mg N kg-1 and 20 mg Cd kg-1 month-1). Under Cd stress, exogenous NH₄HCO₃ increased the biomass (48.0-78.2%), root development, nutrient content, and Cd accumulation (149.2%). In rhizosphere soil, exogenous NH₄HCO₃ decreased the soil pH and NH4+-N content but increased the NO3--N content, available phosphorus (AP), and soil enzyme activities. Exogenous NH₄HCO₃ also reshaped the composition, structure, and co-occurrence patterns of the rhizosphere fungal community, altering the relative abundances of saprotrophic and ectomycorrhizal fungi, such as Rhizoctonia, Peziza, and Exophiala. Moreover, Rhizoctonia and Peziza were positively and negatively correlated with AP, alkaline phosphatase, root biomass, root surface area (RA), fine root surface area (FRA), and Cd uptake efficiency, respectively. Exophiala was positively correlated with root biomass, RA, and FRA. Overall, exogenous NH₄HCO₃ modulates rhizosphere soil properties and reshapes fungal communities, which may improve plant growth and enhance Cd phytoaccumulation.
Feifei Tian, Lianghua Chen, Jiaxuan Mi et al.· International journal of phy...· 0 citations
The phosphatidylethanolamine-binding protein (PEBP) gene family plays essential roles in flowering regulation, plant development, and stress responses. However, its characteristics in Osmanthus fragrans remains largely unexplored. Here, a genome-wide analysis was conducted to comprehensively investigate the OfPEBP gene family. A total of 11 OfPEBP genes were identified and classified into three subgroups: FT-, TFL1-, and MFT-like. Genes within the same subgroup exhibited similar motif compositions and exon–intron structures. Promoter analysis revealed abundant light- and hormone-responsive cis-elements. Population genetic analyses identified significant differentiation in OfPEBP3, OfPEBP7, and OfPEBP8, with their single nucleotide polymorphisms (SNPs) and haplotypes closely associated with seasonal flowering phenotypes. DNA methylation profiling indicated that CpG and CHG methylation predominated across the OfPEBP family and remained relatively stable during flower development, whereas OfPEBP6, OfPEBP9, and OfPEBP10 displayed higher methylation levels. Segmental duplication was identified as the primary driver of family expansion, and duplicated gene pairs experienced strong purifying selection. Expression analyses revealed tissue-specific expression patterns and differential responses to temperature, ethylene, and DNA methylation inhibitor (Aza) treatments. These findings provide useful insights into the potential involvement of OfPEBP genes in seasonal flowering and offer candidate genetic resources for future functional studies and molecular breeding in O. fragrans.
Hui Xia, Yuanhang Wu, Jie Yang et al.· Horticulturae· 0 citations
