BMC Plant Biology最新文献

Background: Plastid genomes (plastomes) in land plants typically retain a conserved quadripartite structure; yet some angiosperm lineages exhibit extensive structural instability and accelerated sequence evolution. Here, we present a comparative plastome analysis of six species from the subgenus Lychnis (genus Silene, Caryophyllaceae) integrated with previously published plastomes.

Results: We identify eight large-scale inversions, three independent shifts of the inverted-repeat (IR) boundary, and a marked proliferation of dispersed repeats, implicating repeat-mediated recombination and altered recombination control in driving plastome reorganization. Gene content varied among Lychnis species, including the loss or pseudogenization of accD, infA, and rpl23. Transcriptome data reveal nuclear-encoded homologues with chloroplast-targeting signals, indicating functional replacement via plastid-to-nucleus gene transfer and recruitment of pre-existing nuclear paralogues. Plastid phylogenomic analyses recover the subgenus Lychnis as a strongly supported, monophyletic and early-diverging lineage within the genus Silene, showing that structural changes and substitution rate acceleration have arisen independently of those in other subgenera. Across the genus, synonymous and nonsynonymous substitution rates are elevated in a subset of non-photosynthetic genes, including accD and clpP, with lineage-specific episodes of positive selection detected on several branches.

Conclusions: Together, these results point to a complex interplay between recombination dynamics, shifts in selective regime and plastid-nuclear interactions, and underscore plastome instability as an important driver of genome evolution within Silene and more broadly across angiosperms.

Accumulation of heavy metals (HMs) and sulfates in farmland near mines is one of the most serious environmental problems posing a threat to crops and human health. Moderate sulfate alleviates the toxicity of HMs in crops, but the impact of high sulfate on crops in HM-contaminated soil remains unclear. Hence, we integrated physiological, transcriptomic and metabolomic profiling to investigate the effect of high sulfate on Chinese cabbage (Brassica chinensis L.) under HMs through controlled pot experiments. According to our results, compared with the HMs only group, the growth indicators of Chinese cabbage in the HMs plus high sulfate group decreased by 11.94% to 49.19%, and photosynthesis was significantly inhibited (p < 0.05). Notably, potential biomarkers indicating high sulfate were identified: catalase, fructose-bisphosphate aldolase 2, senescence-associated gene 21, ferritin-1, and 2-Aminoadipic acid. Mechanistically, high sulfate intensified oxidative damage by suppressing the synthesis of glutathione (with a 43.43% reduction) and γ-aminobutyric acid (with a 15.19% decline), consequently resulting in a 21.79% increase in reactive oxygen species (ROS) within the leaves. The excessive accumulation of ROS appeared to directly initiate programmed cell death, induced cellular damage in roots and leaves, and might enhance autophagic degradation of chloroplasts and the endoplasmic reticulum. Then, photosynthesis, sucrose synthesis, amino acid anabolism, and energy production pathways were disrupted, leading to the further reduction of Chinese cabbage biomass. Consequently, this study emphasized the harmful effects of high sulfate on Chinese cabbage in HM-contaminated soil through disrupting the ROS clearance function of Chinese cabbage.

Background: The agronomic quality of cutting-propagated strawberry seedlings is a critical determinant of subsequent field performance and economic returns in the annual production of fresh-market strawberries. Although far-red light (FR) has been well established as a key regulator of plant architecture and productivity in many horticultural crops, its specific physiological roles during the strawberry seedling establishment stage remain poorly understood. Thus, investigating whether end-of-day far red (EOD-FR) light treatment can effectively enhance the growth vigor and overall development of strawberry runners addresses a significant knowledge gap, with direct implications for commercial seedling production systems.

Methods: The experiment investigated the effects of 0 (CK), 3 h, 6 h, and 9 h EOD-FR durations on strawberry cuttings (Fragaria × ananassa Duch. cv. Benihoppe). The 60-d period experiment was conducted in a solar greenhouse, employing a completely randomized block design. The sampling was carried at 30 d and 60 d to assess physiological and morphological responses of strawberry seedlings.

Results: Compared with the control (CK), 6 h EOD-FR supplementation markedly enhanced seedling growth, including increases in height, leaf area, petiole diameter and length, biomass accumulation, root development and vigor index. In addition, anatomical observations revealed that while prolonged EOD-FR exposure led to reduction in leaf thickness, the 6 h EOD-FR increased the number of vascular bundles in petioles and accelerated floral bud differentiation. The physiological analysis showed that 6 h EOD-FR supplementation enhanced net photosynthetic rate and stomatal conductance, and water use efficiency. This was observed alongside increased activities of antioxidant enzyme and greater accumulation of osmolytes, including free amino acids, soluble sugars, and proteins. Hormonal profiling indicated that 6 h EOD-FR increased the IAA, Brassinosteroids, and ABA levels in leaves and petioles. However, the marked increase of ABA content and reduce of GA₃ content were only found in shoot apices. Based on membership function values and principal component analysis, the order of treatment performance (6 h > 3 h > CK > 9 h) was consistent across both 30-d and 60-d experimental durations.

Conclusion: In summary, supplementation with 6 h EOD-FR optimizes photosynthetic performance, strengthens antioxidant capacity, regulates hormone balance, and promotes nutrient accumulation in strawberry seedlings, ultimately leading to enhanced growth and stimulated floral induction.

Climate change is leading to an increase in the frequency and severity of drought events, which will have more negative impacts on forest ecosystems. Due to the complexity of drought event characteristics, tree growth levels, and habitats, it is challenging to clarify the adaptation patterns of trees to drought events. Therefore, we used tree-ring width data from several conifer species to quantify drought-induced growth loss and post-drought recovery, and evaluated the drivers of these processes using linear mixed-effects models. The results showed that wet conditions significantly enhanced radial growth, whereas drought events markedly suppressed it. Consecutive wet and dry events counteracted each other's effects. However, two consecutive years of drought did not inhibit radial growth more severely than a single drought event. Higher growth loss led to reduced growth recovery, while better post-drought wetness interrupted drought legacy effects and promoted rapid tree recovery. Pre-drought growth levels are key to adaptation, higher levels reduce losses and boost recovery. In addition, both tree growth loss and growth recovery were strongly related to elevation and drought sensitivity. In summary, we conclude that better pre-drought growth levels of trees enhance their growth adaptation to drought events, while better post- drought wetness promotes rapid recovery and compensates for drought-induced losses.

Background: Rose accounts for over one-third of the global cut flower industry, with pink varieties dominating the market. However, research on the mechanism for pink petal formation in rose is still insufficient.

Results: To elucidate the molecular mechanism of rose petal pigmentation, we performed metabolome and transcriptomics analyses of two rose progenies derived from the hybridization of Rosa chinensis var. Spontanea and 'Old Blush', which exhibit light pink (LP) and dark pink (DP) flowers, respectively. Metabolome analysis identified pelargonidin derivatives as major anthocyanins in DP, while cyanidin 3-O-coumaroylglucoside-5-O-glucoside (Cy3cG5G), as a key anthocyanins, was exclusively detected at S3 in DP, perfectly matching the formation timing of the dark pink phenotype. Transcriptomics data revealed differentially expressed genes involved in flavonoid and anthocyanin biosynthesis, corresponding to varying anthocyanin levels in petals, between the two roses. In addition, integrated analysis uncovered molecular networks regulating petal pigmentation and identified transcription factors RcMYB308 and RcMYB1b as key players in the accumulation of anthocyanins and flavonol derivatives. Here, yeast two-hybrid (Y2H) and bimolecular fluorescence complementation (BIFC) assays demonstrated that these proteins form MYB-bHLH complexes with RcEGL1 to activate anthocyanin biosynthesis genes. The dual-luciferase (Dual-LUC) assays demonstrated that RcMYB308 activated RcF3'H, thereby bolstering anthocyanin accumulation, while RcMYB1b could bind to the RcF3'H promoter and exert a negative regulatory effect on RcF3'H. The overexpression and silencing of RcMYB308 in petals revealed that it facilitated anthocyanin accumulation by specifically regulating RcF3'H-mediated cyanidin synthesis, resulting in dark pink pigmentation.

Conclusion: Collectively, our analysis of two pink rose progenies reveals that the RcMYB308-RcEGL1 module regulates petal color divergence during development via direct targeting of the RcF3'H promoter. These findings clarify key elements of the gene-metabolism network regulating rose petal coloration and provide a theoretical basis for rose flower color genetic improvement.