BMC Plant Biology最新文献

Somatic embryogenesis (SE), the process by which differentiated somatic cells are reprogrammed to form embryos, represents a unique manifestation of plant cell totipotency. Despite its fundamental and applied importance, the molecular mechanisms that initiate embryogenic reprogramming remain largely unknown, mainly because explant tissues are cell-type heterogeneous and contain only a small fraction of SE-competent cells. Here, we applied fluorescence-activated nuclei sorting (FANS) in Arabidopsis thaliana to isolate cells expressing the WOX2 gene, a marker for early embryogenesis. Comparative transcriptomic analysis of WOX2⁽⁺⁾-positive and WOX2^(-)-negative nuclei revealed that genes up-regulated in the embryogenic nuclei were strongly enriched in biological processes related to embryo and tissue development, while down-regulated transcripts were linked to primary metabolism, suggesting a transcriptional switch from differentiated to totipotent identity. Several transcription factor genes showed strong induction, including MYB46, ZAT14, MYB98, GRF7, MYR2, and TCP19. Functional analyses using β-estradiol-inducible overexpression and loss-of-function mutants confirmed that these genes modulate embryogenic competence. In particular, MYB46 and ZAT14 emerged as candidate regulators acting downstream of WOX2 to coordinate complementary aspects of cell wall remodeling required for cellular isolation and the acquisition of embryogenic identity. These findings reveal an early, WOX2-centered regulatory network that precedes the activation of canonical SE regulators such as LEC2 and BBM, uncovering a new transcriptional layer of totipotency control.

Drought is one of the major abiotic stress factors limiting the growth, development, and yield of potato (Solanum tuberosum L.). Melatonin, a novel plant hormone, has recently shown significant potential in enhancing plant stress resistance. However, its regulatory mechanisms in response to drought stress in potato remain unclear. In this study, potato seedlings were treated with different concentrations of exogenous melatonin (50, 100, and 150 µmol L⁻¹) under controlled drought conditions to systematically evaluate their physiological and molecular responses. The results demonstrated that appropriate melatonin application, especially at 100 µmol L⁻¹ effectively alleviated drought-induced growth inhibition, oxidative stress, and photosynthetic impairment. This was evidenced by increased plant height, enhanced photosynthetic efficiency, reduced reactive oxygen species (ROS) accumulation, decreased cell death and lipid peroxidation, as well as elevated antioxidant enzyme activities (superoxide dismutase - SOD, catalase - CAT, peroxidase - POD) and levels of osmoprotectants (proline - Pro and soluble sugars - SS). Transcriptome analysis revealed that melatonin modulates numerous drought-responsive differentially expressed genes (DEGs), including multiple transcription factor (TF) families (e.g., MYB, NAC, ERF), and pathways related to photosynthesis, antioxidative metabolism, hormone signaling, and carbon metabolism. Furthermore, weighted gene co-expression network analysis (WGCNA) and Mfuzz clustering identified key gene modules and central hub genes strongly associated with photosynthetic performance and antioxidant indicators. Overexpression of StMYB and StAPX in Arabidopsis significantly enhanced drought tolerance by improving antioxidant enzyme activities and maintaining membrane stability under water-deficit conditions. This study provides a theoretical foundation for applying melatonin in potato drought stress mitigation and lays a molecular basis for developing melatonin-based agronomic strategies for improving drought tolerance.

This study examined the associations between genotypic variation, environmental conditions, and the phytochemical composition, mineral content, and antioxidant capacity of wild Prunus cerasifera genotypes in diverse ecogeographic regions of Eastern Anatolia (Türkiye). Thirteen genotypes were evaluated for morphological, physicochemical, and biochemical traits under varying climatic conditions, including temperature, humidity, precipitation, and solar radiation. Principal Component Analysis (PCA) revealed the multidimensional nature of this variation, indicating that environmental variables, particularly temperature and solar radiation, were associated with differences in mineral accumulation and phenolic compound levels. Warmer and sunnier environments were linked to higher nutritional density, while genotypes from more humid conditions exhibited a "dilution effect," reflecting a balance between fruit size and bioactive compound concentration. Substantial variation was observed among genotypes, with up to a five-fold difference in total phenolic content and marked differences in mineral composition, highlighting the broad genetic diversity in wild populations. Certain genotypes showed notable nutritional characteristics: 44PC01 had the highest flavonoid content and antioxidant capacity, 23PC05 accumulated higher levels of macroelements (Mg, K, Ca), and 44PC03 and 44PC07 contained the highest microelements (Fe, Zn, Cr). Partial correlation analysis, after accounting for genotypic differences, suggested that genetic background was the main source of variation in fruit quality traits, while associations with environmental variables were comparatively weaker. Overall, these findings provide evidence of phenotypic and biochemical diversity among wild P. cerasifera genotypes and emphasize their value as genetic resources for conservation and future multi-year breeding studies.