Plant Molecular Biology最新文献

Drought is a major natural disaster that affects plant growth. Agropyron mongolicum possesses a wide range of drought tolerance genes acquired during its long evolution and adaptation to harsh environments. However, the regulatory mechanisms for drought resistance in A. mongolicum are complex, limiting the development and utilization of gene resources in response to drought stress. In this study, we examined differences in morphological, physiological, metabolite and transcript levels between the drought-tolerant (T) and drought-sensitive (S) genotypes of A. mongolicum to identify key metabolites and genes associated with the drought response. The morphological and physiological results suggest that the S genotype is suppressed by drought stress to a greater extent than the T genotype. Based on the metabolome and transcriptome data, we identified that serine/threonine-protein kinase SRK2 (SRK2), peptide chain release factor subunit 1 (eRF1), glutamine synthetase (GS), polyphenol oxidase (PPO), and aspartyl protease family protein (ASP) were highly correlated with key metabolites such as L-γ-glutamyl-L-leucine and γ-glutamylphenylalanine in leaves by co-expression network analysis, and alcohol-forming fatty acyl-CoA reductase (FAR), DNA oxidative demethylase (ALKBH), GDSL esterase/lipase (GELP), beta-fructofuranosidase (INV), and glutamine synthetase (GS) were highly correlated with key metabolites such as Trp-Glu-Ile and citric acid diglucoside in roots. Moreover, we identified the potential involvement of fatty acid degradation and glycolysis/glucogenesis pathways in the enhancement of drought tolerance in A. mongolicum. This study provides a foundation for genetic engineering studies of drought resistance in Poaceae plants.

Previous studies have shown that BPH1 represses the abscisic acid (ABA)-mediated cellular responses. To further understand the mechanism of action of BPH1 in ABA signaling, the putative binding partners of BPH1 were investigated. Arabidopsis stress associated protein 9 (AtSAP9), which acts as a positive regulator of ABA signaling, has been identified as a BPH1-binding protein. Both BPH1 and AtSAP9 proteins were localized in the nucleus and cytosol, and a direct interaction between BPH1 and AtSAP9 was confirmed using yeast two-hybrid and bimolecular fluorescence complementation assays. The cell-free degradation assay indicated that MBP-AtSAP9 protein was degraded more slowly when incubated with the bph1 extracts than with Col-0 extracts, and that its degradation was dependent on the presence of the proteasome inhibitor MG132. Negative regulation of AtSAP9 protein stability by BPH1 was also confirmed in planta. Despite the E3 ubiquitin ligase activity of AtSAP9, the protein level of BPH1 was unaffected by AtSAP9. Collectively, these results indicate that BPH1, a CRL3 substrate receptor, functions as a repressor of ABA signaling, potentially through ubiquitin-proteasome system-dependent degradation of AtSAP9.

Macrophytes are critical primary producers in freshwater ecosystems and offer potential as crop resources to support the growing human population. They are also widely used to mitigate eutrophication. Aquatic plants adapt themselves to the more complicated, changeable, and unstable conditions compared to terrestrial plants, especially the fluctuating nutrient environments. Nitrogen (N) and phosphorus (P) are the key nutrient elements for plants, and their biogeochemical cycles have been significantly disrupted by anthropogenic activities in diverse ecosystems. However, there is still a lack of comprehensive understanding about the adaptive mechanisms of N and P stress in aquatic plants. In this study, the response mechanisms in the macrophyte Spirodela polyrhiza under various nutrient conditions were analyzed. S. polyrhiza showed universal changes under nutrient deficiencies at the physiological level, including enhanced root growth, lower Chl content, higher Root-Frond ratio, and starch content. Genes involved in nutrient acquisition and remobilization, carbon metabolism, transcriptional regulation, hormones, and antioxidant systems were identified. Physiological and transcriptional changes revealed that the macrophyte S. polyrhiza adopts a nutrient acquisition-prioritization strategy under nutrient deficiency conditions, employing strategies similar to those observed in terrestrial plants. Post-transcriptional regulatory networks also highlighted the critical role of non-coding RNAs nutrient stress responses. Overall, S. polyrhiza employs integrated physiological and molecular strategies to cope with nutrient deficiency in aquatic environments. This study provides comprehensive insights into its adaptive responses and offers a valuable genetic resource for further novel gene discovery and functional analysis.

Proper development of floral organs is essential for reproductive success and grain yield in wheat. However, the molecular mechanisms regulating wheat floral organ development remain largely unknown. In this study, we characterized the role of the wheat TaEPFL1 gene in floral organ development and its association with ethylene signaling. TaEPFL1 was highly expressed in immature spikes of the pistillody mutant HTS-1, particularly during the pistil and stamen specification stages. Its expression was responsive to both exogenous ethylene and the ethylene inhibitor 1-Methylcyclopropene (1-MCP). Overexpression of TaEPFL1 in transgenic wheat led to shortened stamens, defective pistils, male sterility, and complete reproductive failure. Histological analysis revealed delayed tapetum degradation, indicating disrupted programmed cell death (PCD). Gas chromatography (GC) showed significantly reduced ethylene production and release in TaEPFL1-overexpressing lines. Similar floral defects were observed in wild-type plants treated with 1-MCP. Transcriptome and qRT-PCR analyses further confirmed downregulation of multiple ethylene biosynthesis-related genes, including three homologs of TaACO. These results suggest that TaEPFL1 negatively regulates ethylene biosynthesis by repressing TaACO expression, thereby impairing floral organ differentiation. We propose a feedback model in which ethylene induces TaEPFL1, which in turn suppresses ethylene production to maintain hormonal homeostasis. This study reveals a novel regulatory mechanism linking TaEPFL1 to ethylene-mediated floral development and provides new insights for improving wheat fertility through molecular breeding.