BMC Plant Biology最新文献

The phytohormone brassinosteroid (BR) regulate various developmental and physiological processes in plants. However, the function of BR during early seedling development stage in rapeseed is largely unknown. To understand the effects of exogenous BR during early seedling development, the ZS11 and BR-INSENSITIVE (bin2) mutants were treated with BR before seed sowing and seed germination stage under 16/8 hours light/dark cycle. The phenotype results indicated that BR promotes only seedling establishment but not seed germination stage in ZS11, while no function in bin2 mutants. Since BRs play a crucial role in regulation of developmental transition between growth in the dark (skotomorphogenesis) and growth in the light (photomorphogenesis), the ZS11 and bin2 mutants were treated with BR under continuous light and dark. The BR treatment also showed the same functions as 16/8 hours light/dark cycle. To understand the function of BR on expression levels, the differentially expressed genes (DEGs) and differentially expressed metabolites (DEMs) between mock- and BR-treated seedlings were explored. A total of 234 significantly DEGs were identified between the mock- and BR-treated groups by transcriptomic analyses. These DEGs were markedly enriched in BR biosynthesis, pentose and glucuronate interconversions and plant hormone signal transduction pathways. Meanwhile, a total of 145 DEMs were identified through metabolomics analyses, with a significant enrichment in lipid substances. Interestingly, some genes and metabolites associated with auxin pathway were identified, which exhibited up-regulation in both DEGs and DEMs after BR treatment. Subsequently, functional enrichment analyses revealed that the majority of DEGs and DEMs were primarily enriched in ascorbate and aldehyde metabolism, arginine and proline metabolism, tryptophan metabolism (the main route for auxin synthesis) and cyanogenic amino acid metabolism. Furthermore, it was found that glutamate was up-regulated in nitrogen metabolism, glyoxylate and dicarboxylate metabolism, and arginine and proline metabolism pathways. These indicated that the glutamate signaling pathway was a key regulatory pathway for exogenous BR to induce seedling establishment. These evidence implied that exogenous BR treatment lead to up-regulation of auxin-related genes expression, then promoted seedling establishment in rapeseed.

Curcuma wenyujin, a perennial herb of the ginger family, is renowned for its significant medicinal properties. Phosphorus (P), a vital nutrient for plant growth and development, has seen its levels, particularly organic P, increase in the soils of agricultural regions in southern China, presenting new challenges for nutrient management. This study aimed to uncover the molecular responses of C. wenyujin seedlings to both normal and high phosphorus (HP) conditions, shedding light on their adaptation strategies to P stress. Through transcriptome and metabolome analyses of the seedlings under normal and HP conditions, we identified 1,793 metabolites, with 195 showing differential expression. Notably, KEGG enrichment analysis highlighted 35 significantly differential accumulation metabolites (DAMs). Comparing the control group (CK) and HP treated groups (T) revealed 840 differentially expressed genes (DEGs), pinpointing the molecular divergences in response to varying P levels. Importantly, we found a potential gene, purple acid phosphatase 17 (pap17) that may cofer HP stress conditions in C. wenyujin. That elucidated the response variations of C. wenyujin seedlings to diverse P concentrations. The research suggested that C. wenyujin may adjust to varying P levels by modulating metabolites and genes linked to amino acid and phenylpropane metabolism. It highlighted the sophisticated mechanisms plants utilize to manage P stress, offering insights into their survival tactics in settings where P availability changes.

Background: The genus Taxus (yew) is the sole producer of the paclitaxel with anticancer properties. The rising demand for plant-derived medicines has led to the overexploitation of various species and ecosystem degradation, which is further worsened by climate change. Taxus baccata L. cell culture represents a promising commercial approach for the production of taxanes. A variety of elicitors and signaling molecules have been utilized to enhance production taxanes with results significantly affected by several factors, including the specificity of the stimulant, its concentration, the timing of inoculation, and the duration of treatment. To date, no studies have revealed that the elicitors derived from Fusarium graminearum enhance 10-deacetylbaccatin III (10-DABIII) and paclitaxel production in T. baccata suspension cell cultures. Added to that, we evaluated the impact of these fungal elicitors on cell viability, growth, phenylalanine ammonia-lyase (PAL) activity, and the production levels of paclitaxel and 10-DABIII.

Results: We investigated the effects of autoclaved cell extracts (ACE) and autoclaved culture filtrates (ACF) derived from F. graminearum on the suspension cell cultures of T. baccata. Our results indicated that the highest paclitaxel production, 9.438 µg/g dry weight, was achieved with a 10% autoclaved culture filtrate treatment. Furthermore, the autoclaved cell extracts significantly enhanced the levels of 10-DABIII, resulting in a remarkable 7.38-fold increase at a 5% concentration compared to the control on day 21. Treatment of the cell cultures of T. baccata with ACE and ACF decreased cell viability by 31% and 23%, respectively, compared to an 18% reduction observed in the control group after 21 days. The fungal elicitors initially induced the activity of PAL in the cell cultures, followed by a subsequent decline in this enzymatic activity.

Conclusions: Our study offers valuable insights for biotechnological applications in pharmaceutical and agricultural industries. Moreover, this research contributes to a better understanding of elicitor-mediated improvements in paclitaxel biosynthesis, paving the way for sustainable and efficient production in T. baccata cell cultures.

Background: Huanglongbing (HLB) is a devastating bacterial disease caused by the bacterium Candidatus Liberibacter asiaticus (CaLas) that affects the citrus industry worldwide. This study investigated the response of two pummelo x finger lime hybrid siblings to natural infection with CaLas. The hybrids were identified primarily using leaf morphology and molecular marker assessments and were selected for further studies on the basis of the CaLas titers in leaf petioles.

Results: HLB-infected budwood from the selected hybrids (PFL 2-61 and PFL 1-11), as well as the two parental plants, were propagated by grafting onto Swingle citrumelo rootstocks for further evaluation. Plant samples were collected two years after grafting for analysis. Leaves of PFL2-61 exhibited decreased CaLas titers compared with those of PFL 1-11. Additionally, we recorded increased chlorophyll content, total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity in PFL 2-61 compared to PFL 1-11 and the parents. We subsequently conducted a detailed investigation of these two hybrid siblings using transcriptome analysis. Among the 20,675 differentially expressed genes (DEGs) identified, 1,416 were downregulated in PFL 2-61 compared with PFL 1-11, whereas 326 were upregulated. Transcriptome analysis revealed that many of the DEGs were associated with the cell wall structure, redox homeostasis, and biotic stress responses. Moreover, key genes related to the biosynthesis of secondary metabolites and phytohormones, including PAL1, jasmonate-related genes, and WRKY transcription factors, were upregulated in the tolerant hybrid (PFL 2-61). In contrast, three transcripts associated with the Sieve Element Occlusion N-Terminus (SEO_N) domain were downregulated in the tolerant hybrid (PFL 2-61).

Conclusions: Our findings provide valuable insights into the molecular mechanisms of tolerance and susceptibility to HLB in finger lime derived hybrids, highlighting the potential of this citrus species towards developing disease-tolerant varieties.

Tarocco is a prevalent blood-orange variety in China, has a bud variant identified in Wenzhou City. To characterize the quality traits and molecular mechanisms underlying inhibition of anthocyanin synthesis in this variety, we collected fruits of Tarocco (WT) and the bud variant Ouya (MT) at nine developmental stages. Their anthocyanin, soluble sugar, and organic acid profiles were examined, and transcriptomes and metabolites were analyzed at three developmental stages. The results revealed that MT is a new blood orange variety with weak anthocyanins and a better sugar-acid ratio than the WT. The content of anthocyanin in MT fruits were significantly lower than those in WT fruits, especially cyanidin-like anthocyanins, while the flavone contents exhibited no remarkable variation. A total of 64 differentially expressed genes (DEGs), including five transcription factors (TFs), five methylation-related genes, and one flavonoid biosynthesis gene, were identified between WT and MT at three fruit developmental stages. The potential regulatory networks of these TFs were further constructed using weighted gene co-expression network analysis.Furthermore, in MT fruit treated with the 5-azacytidine, we observed hypomethylation of anthocyanins accumulated in the pulp and the promoters and genebodies of some anthocyanin synthesis-related genes. These results provide new insights into the influence of DNA methylation on anthocyanin accumulation in MT and also provide support for the promotion of MT as a new variety.

Background: Investigating the responses of Salix matsudana to homogeneous and heterogeneous salt concentrations is crucial for the development and optimal use of saline-alkali lands. This study utilized a split-root experiment, positioning the roots of Salix matsudana in both low-salinity and high-salinity areas. Using a salt-free treatment (0/0) as a control, we applied two homogeneous salt treatments (171/171, 342/342 mmol L^- 1 NaCl) and two heterogeneous salt treatments (0/342, 171/513 mmol L^- 1 NaCl) to assess growth characteristics, photosynthesis, ion distribution, root vigor, and water uptake under salt stress.

Results: The results showed that leaf biomass under heterogeneous salt treatments (0/342 and 171/513 mmol L^- 1 NaCl) was 1.2 and 1.7 times greater, respectively, than under homogeneous treatments (171/171 and 342/342 mmol L^- 1 NaCl). Root biomass in the low-salinity areas of the heterogeneous treatments was 2.1 and 1.3 times higher than in the high-salinity areas, with water uptake 1.6 and 1.5 times greater. This improvement was attributed to significantly enhanced root vigor in the low-salinity areas, which promoted water uptake and mitigated the inhibitory effects of salt concentration on aboveground growth and stomatal limitation. Consequently, this resulted in higher net photosynthesis rates, elevated levels of K⁺, Ca²⁺, and Mg²⁺, and reduced Na⁺ content in the leaves. Moreover, micro-area X-ray fluorescence imaging revealed that, under salt stress, Na⁺ was uniformly distributed across the leaves, while K⁺ accumulated in the main veins and, under heterogeneous salt stress, was translocated downward and redistributed to the roots in the low-salinity areas, further promoting ion balance. Compensatory growth occurred in the roots of the low-salinity areas, supporting normal plant growth.

Conclusions: Compared to homogeneous salt stress, heterogeneous salt stress significantly alleviated the growth and physiological damage in Salix matsudana. Reducing salt concentrations in localized areas of saline-alkali soils may help mitigate the detrimental effects of salt stress, offering a theoretical basis for adaptive cultivation in saline-alkali regions.

Background: Tubulin proteins, the main components of microtubules in all eukaryotes, are involved in numerous aspects of plant morphogenesis and adaptation to the environment. In woody plants, microtubules are closely associated with the orientation of cellulose microfibril deposition in the secondary xylem cells and thereby exert an influence on the strength and flexibility of wood. Three major types of tubulin proteins-α-, β- and γ-tubulin-are ubiquitously present in all flowering plants, with α- and β- tubulin serving as basic subunits of microtubules and γ-tubulin directing microtubule nucleation. Compared with herbaceous plants, information on tubulin gene family has been limited in forest trees. This study aimed to characterize the tubulin gene family in the model forest tree Populus deltoides.

Result: Based on the whole genome sequence of P. deltoides, 25 PdTubulin genes were identified, including 6 PdTUAs, 17 PdTUBs, and 2 PdTUBGs were identified, with an uneven distribution across 14 chromosomes. Unlike Arabidopsis, which has only three pairs of tubulin paralogs, nearly all PdTubulin were paralogous duplicates, primarily generated by p-whole genome duplication (WGD), γ-WGD, or segmental duplication, indicating multiple rounds of gene family expansion. After the duplication events, the number of TUA genes in Populus was more strictly constrained compared to TUB genes. All paralogous and orthologous tubulin pairs have been under strong purifying selection. Expression analysis revealed that each PdTubulin gene was preferentially expressed in one of three organs: root, leaf, or stem. 5 PdTUB paralogs exhibited similar expression patterns, suggesting potential redundancy. Additionally, expression analysis in male and female floral buds across developmental stages indicated that different members might be involved in sex-specific processes.

Phenylalanine (Phe), an aromatic amino acid, is a key precursor of flavonoids, which are crucial for plant growth and development. Arogenate dehydratase (ADT) catalyzes the final step in Phe biosynthesis. This study identified eleven ADT genes in G. hirsutum, twelve in G. barbadense, six in G. arboreum, and six in G. raimondii. Among them, GhADT5 exhibited the highest upregulation under alkali stress. Silencing GhADT5 using virus-induced gene silencing (VIGS) reduced cotton tolerance to alkali stress. GhADT5 silencing also led to decreased plant phenylalanine content, total flavonoid content, and activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). These reductions caused intracellular accumulation of Malondialdehyde (MDA) and reactive oxygen species (ROS). This oxidative damage ultimately reduced tolerance to alkali stress. In addition, silenced plants displayed reduced stomatal aperture, cellular deformation, and irregular intercellular breaks in the leaf epidermis. In summary, these findings suggest that GhADT5 may enhance resistance to alkali stress by regulating enzymatic and non-enzymatic antioxidant systems. This study highlights the role of GhADT5 under alkali stress and provides novel insights for breeding cotton varieties with improved stress tolerance.

Background: Soil salinity is a major environmental concern that affects the production of salt-sensitive crops such as cucumbers by limiting their growth and development. Wood vinegar is used as a biostimulant in agriculture to enhance crop productivity and improve the plant's defense system against pathogens, while studies show that it can also protect against oxidative stresses. A factorial experiment was arranged based on a randomized completely design with three replicates and carried out to mitigate the negative effects of sodium chloride (NaCl) on cucumber seedlings through pistachio wood vinegar (PWV) foliar spraying. The seedling was sprayed at the three-leaf stage of growth by PWV (0, 1500, and 3000 ppm) and salinity stress (0, and 150 mM NaCl) was imposed at the five-leaf stage gradually (from 25 to 150 mM NaCl) in the modified Hoagland's solution.

Results: The intense salinity stress reduced the fresh and dry mass of root and shoot by 25, 5, 34, and 13%, and decreased chlorophyll a, b, total, and carotenoids by 14, 45, 28, and 44%, respectively compared to the control. Also, in the treated plants with PWV decreased levels of total protein (14%). While PWV treatment decreased the negative effects of the intense salinity stress and enhanced the fresh mass root (41%), dry mass shoot (33%), shoot length (23%), leaf area (34%), leaf number (63%), Chl a (14%), Chl b (11%) and carotenoids (56%). Under the intense salinity stress, the foliar spraying of PWV, 3000 ppm, decreased the reactive oxygen species (ROS) and malondialdehyde (MDA) by 7 and 10%, respectively compared to the control.

Conclusions: This study shows that the use of PWV (1500 ppm) via its nutrient and bioactive components is effective in improving the negative effects of the salinity (150 mM NaCl) in cucumber seedlings.