Protoplasma最新文献

Cerium oxide nanoparticles (CeO₂-NPs) have been widely applied worldwide. In the field of agriculture, they have gained attention for their ability to promote seed germination, root elongation, and biomass accumulation in plants, as well as to increase plant resistance to various abiotic stresses. However, the underlying molecular mechanisms remain to be elucidated. Limited research has been conducted on whether CeO₂-NPs can help plants mitigate damage caused by UV-B stress. In this study, Arabidopsis thaliana was selected as the research subject to investigate the effects of CeO₂-NPs on the resistance of plant roots to UV-B stress at both the physiological and molecular levels. Our findings demonstrated that 120 mg/mL CeO₂-NPs significantly alleviated UV-B-induced damage to the root system of Arabidopsis thaliana. Specifically, CeO₂-NPs increased the activities of the root tip antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), reducing oxidative stress. The results from GUS staining and GFP fluorescence assays conducted on the transgenic lines CYCB1;1-GUS, DR5-GUS, QC25-GUS, and WOX5-GFP indicated that CeO₂-NPs could increase the cell division activity, auxin accumulation, and stem cell niche activity of Arabidopsis thaliana root tips under UV-B stress. Furthermore, observations of GFP fluorescence in the transgenic lines PIN1-GFP, PIN2-GFP, and PIN7-GFP revealed that CeO₂-NPs promoted root growth by inducing the accumulation of auxin transporters. Quantitative real-time PCR (qRT-PCR) analysis revealed that under UV-B stress, CeO₂-NPs upregulated the expression of genes related to antioxidant enzymes, the cell cycle and auxin biosynthesis-related genes in Arabidopsis thaliana root tips while downregulating the expression of genes related to DNA damage repair and stress response. Therefore, CeO₂-NPs have potential value for promoting plant growth and mitigating UV-B stress.

Myrosinase, referred to as thioglucoside glucohydrolase (TGG), plays a crucial role in plant physiology through catalyzing the hydrolysis of glucosinolates into bioactive isothiocyanates. In Arabidopsis thaliana, the myrosinases TGG1 and TGG2 are essential for abscisic acid- and methyl jasmonate-induced stomata closure. Allyl isothiocyanate (AITC), one of myrosinase products, triggers stomatal closure in A. thaliana. We investigated stomatal responses to AITC to clarify the role of TGG1 and TGG2 in Arabidopsis guard-cell signaling. Allyl isothiocyanate at 50 μM and 100 μM induced stomatal closure in the tgg1 and tgg2 single mutants but not in the tgg1 tgg2 double mutant. Furthermore, AITC at 50 μM induced the production of reactive oxygen species and nitric oxide, cytosolic alkalization, and oscillations in cytosolic free calcium concentration in guard cells of both wild-type and mutant plants. These findings suggest that TGG1 and TGG2 are involved in AITC signaling pathway through interaction with signal component(s) downstream of these signaling events, which is not accompanied by hydrolysis of glucosinolates because of the difference in subcellular localization between enzymes (myrosinases) and substrates (glucosinolates).

Repetitive elements are the main components of many plant genomes and play a crucial role in the variation of genome size and structure, ultimately impacting species diversification and adaptation. Alstroemeriaceae exhibits species with large genomes, not attributed to polyploidy. In this study, we analysed the repetitive fraction of the genome of Bomarea edulis through low-coverage sequencing and in silico characterization, and compared it to the repeats of Alstroemeria longistaminea, a species from a sister genus that has been previously characterized. LTR-retrotransposons were identified as the most abundant elements in the B. edulis genome (50.22%), with significant variations in abundance for specific lineages between the two species. The expansion of the B. edulis genome was likely due to three main lineages of LTR retrotransposons, Ty3/gypsy Tekay and Retand and Ty1/copia SIRE, all represented by truncated elements which were probably active in the past. Furthermore, the proportion of satDNA (~ 7%) was six times higher in B. edulis compared to A. longistaminea, with most families exhibiting a dispersed, uniform distribution in the genome. SatDNAs, thus, contributed to some extent to genome obesity. Despite diverging around 29 Mya, both species still share some satDNA families and retrotransposons. However, differences in repeat abundances and sequence variants led to genome differentiation despite their similar sizes and structure.

Diabetes mellitus (DM) and cancer are multifactorial diseases with significant health consequences, and their relationship with aging makes them particularly challenging. Epidemiological data suggests that individuals with DM are more susceptible to certain cancers. This study examined the bioactive properties of Hypericum scabrum extracts, including methanol, hexane, and others, focusing on their inhibitory effects on key enzymes associated with DM and neurodegenerative diseases, such as acetylcholinesterase, butyrylcholinesterase, α-amylase, and α-glucosidase. Additionally, the impact of these extracts on human fibroblast (HDFa) and glioblastoma (U87MG) cancer cells was evaluated. The methanol extract was analyzed for elemental composition using ICP-MS, secondary metabolites, and amino acids via LC-MS/MS and underwent morphological and anatomical characterization. The methanol extract demonstrated notable inhibitory activity, with an IC₅₀ value of < 1 µg/mL against α-glucosidase, surpassing acarbose in efficacy. The flower essential oil exhibited the highest inhibition (79.95%) of butyrylcholinesterase and the strongest acetylcholinesterase inhibition (21.62%). Elemental analysis revealed high concentrations of Na and K, while quinic acid and proline were identified as major metabolites, with proline concentrations reaching 494.0482 nmol/mL in the aerial part extract. The anticancer assays revealed higher cytotoxicity in U87MG glioblastoma cells compared to HDFa fibroblasts, suggesting potential applications for cancer therapy. The plant grows 20-50 cm tall, with yellow flowers and ovoid-ribbed capsules containing brown, reniform seeds. Its leaves are amphistomatic and ornamented, while stems feature striate cuticles and paracytic stomata. The pollen grains are microreticulate with syncolporate apertures. These results underscore the promising therapeutic potential of H. scabrum in managing DM, cancer, and neurodegenerative diseases, with its ability to inhibit key enzymes and show selective cytotoxicity against cancer cells.

Upon exposure to salt stress, calcium signaling in plants activates various stress-responsive genes and proteins along with enhancement in antioxidant defense to eventually regulate the cellular homeostasis for reducing cytosolic sodium levels. The coordination among the calcium signaling molecules and transporters plays a crucial role in salinity tolerance. In the present study, twenty-one diverse indigenous rice genotypes were evaluated for salt tolerance during the early seedling stage, and out of that nine genotypes were further selected for physio-biochemical study. Further analysis identified potential salt-tolerant and salt-sensitive genotypes with tolerant lines exhibiting lower Na⁺/K⁺ ratio. Plant phenotype clearly documented the root architectural changes among the most salt-tolerant and sensitive genotypes, while the histo-biochemical DAB and NBT staining and in-gel SOD activity clearly revealed the differential ROS accumulation between the contrasting genotypes and their antioxidant activity. Ultrastructural study depicted stronger UV autofluorescence in the hypodermal and vascular bundle regions, while phloroglucinol staining displayed intense coloration in the vascular bundle region of Bhutmuri, the salt-tolerant genotype, compared to Manipuri Black, the salt-sensitive one showing differential lignification among the contrasting genotype to combat salt stress. Based on expression study, our proposed model depicted immediate upregulation (short-term) of OsSOS3 and OsNHX1 along with gradual upregulation of OsHKT and downregulation of OsSOS1 throughout the stress period to protect the tolerant plant through signaling cascade, while the inadequate upregulation of OsSOS3, OsNHX1, and OsHKT under early stress, coupled with poor coordination between the expression of OsSOS1 and OsSOS3 genes, makes the plant salt sensitive.

Eclipta prostrata belongs to the Asteraceae family. The plant contains bioactive compounds like wedelolactone (WDL) and demethylwedelolactone (DW). Its transcriptomic information engaged with secondary metabolite biosynthesis is not available. Based on differential accumulation of WDL and DW in root, shoot of the mature plant, we performed comparative de novo transcriptome of root and shoot tissue in three independent biological replicates and generated 49820 unique transcripts. Annotation resulted in significant matches for 43,015 unigenes. Based on differential gene expression data, we found WDL biosynthesis-related transcripts, which were mainly upregulated in shoot. Finally, 13 selected differentially expressed transcripts related to WDL biosynthesis that were validated by qRT-PCR. Detailed tissue-specific metabolite and transcript profiling revealed that DW highly accumulated in root and WDL accumulation was high in aerial part along with transcripts. For WDL pathway exploration, we did integrated profiling of 08 metabolites and 13 transcripts and witnessed that only naringenin, apigenin, DW, and WDL were detected in different developmental stages. Taking leads from the findings, we postulated that naringenin to apigenin pathway is one potential route for WDL biosynthesis. Moreover, wound stress led to accumulation of DW and WDL and related biosynthetic transcripts. Furthermore, the selected enzymes were subjected to molecular docking and binding studies for the predicted substrates involved in crucial and advance steps of WDL biosynthesis. A comprehensive analysis integrating de novo transcriptomics, metabolomics, and molecular docking of targeted proteins paves the way for the elucidation of the putative wedelolactone biosynthesis pathway from E. prostrata.

Microspore culture is an efficient and rapid method that produces doubled haploid (DH) lines for hybrid breeding in crops and vegetables. However, the low frequency of microspore embryogenesis and spontaneous diploidization in Chinese kale still require improvement. In the present work, an efficient microspore culture protocol was constructed and used for DH producing in Chinese kale breeding. The results showed that kinetin (KT) and methylene blue (MB) improved microspore embryogenesis and embryo development. The spontaneous diploidization rates were below 14.48%. Therefore, artificial doubling was used for haploids; the doubled haploid rate was significantly increased, and the highest doubling rate reached 33.75% with pendimethalin. 98 DH lines were obtained in this study. This study also identified the horticultural characters of the DH lines, which showed significant differences between them. All DH lines were self-incompatible. The hybrid crosses were performed using five DH lines selected for the Chinese kale breeding. This study was helpful to accelerate the application of microspore culture and provide DH lines for Chinese kale hybrid breeding.

Previously, it was found that four types of glandular trichomes (GTs) are developed on the surface of all aerial organs in Doronicum species. A detailed study of leaves had shown that only two types of GTs form in them. Nothing was known about any differences of GTs on vegetative and reproductive organs. Current work studies morphological, histochemical and ultrastructural features of two types of GTs arising on floral elements in three Doronicum species. The straight GTs there are on all elements of the inflorescence (peduncle, phyllaries, ray and disk florets); they have a short stalk and do not have a clearly visible head. The capitate GTs are located only on the inflorescence peduncle and phyllaries; the trichomes form a long stalk and a distinct head. The chemical composition of the secretion is confirmed by histochemical reactions. Both types of GTs have the specific ultrastructural features and secretory mechanisms. In capitate GTs, a smooth endoplasmic reticulum is the main organelle of cytoplasm and takes part in a synthesis of the phenolic substances. Phenols accumulate in the numerous small vacuoles and thick cell wall. In straight trichomes, leucoplasts of various shapes with plastoglobuli and peripheral reticulum predominate. Terpenes synthesized in leucoplasts are stored in the subcuticular cavity and are released when the cavity ruptures. The acidic polysaccharides are the additional components of a straight trichome secretion. The studied species of Doronicum differ from each other in localization, size and structure of the GTs.

Stay-green (SG) and stem reserve mobilization (SRM) are two significant mutually exclusive traits, which contributes to grain-filling during drought and heat stress in wheat. The current research was conducted in a genome-wide association study (GWAS) panel consisting of 278 wheat genotypes of advanced breeding lines to find the markers linked with SG and SRM traits and also to screen the superior genotypes. SG and SRM traits, viz. soil plant analysis development (SPAD) value, canopy temperature (CT), normalized difference vegetation index (NDVI), leaf senescence rate (LSR) and stem reserve mobilization efficiency (SRE) were recorded. The trial was conducted in α-lattice design, under control and combined heat and drought stress (HD). Analysis of variance and descriptive statistics showed a significant difference across the evaluated traits. The highest mean of SRE (31.7%) and SRM (0.42 g/stem) was reported in HD, while highest SRE in HD and lowest in control was 52.56% and 15.7%, respectively. Genotyping was carried out using the 35 K Axiom R Wheat Breeder's Array, 14,625 SNPs were kept after filtering. Through GWAS, 36 significant marker trait associations (MTAs) were identified on 16 distinct chromosomes; out of this, 22 MTAs were found under control and 14 MTAs under HD. Candidate genes that code for UDP-glycosyltransferase 73C4-like and protein detoxification 40-like was linked to SPAD and CT respectively. One MTAs was detected for SRM on chromosome 6B that code for wall associated receptor kinase 4 like. These SNPs can be utilized to generate cultivars that adapt to climate change by a marker-assisted gene transfer.

Secretory canals are distributed among seed plants, and their diversity is concentrated in many families of angiosperms, while other internal secretory structures such as secretory cavities have been identified only in Rutaceae, Myrtaceae, and Asteraceae. Identifying and recognizing these two types of secretory structures has been complicated, mainly due to their structural similarities. In this study, the ontogeny of canals and secretory cavities in two species of Asteraceae are described and compared, to understand the structural differences between them and allow the establishment of more appropriate homology hypotheses. Leaves of Bidens odorata and Tagetes tenuifolia in different stages of development, including the apex of the stems, were collected. The samples were processed using the methacrylate technique, and longitudinal and transverse sections were made. The development of both, canals and secretory cavities, is schizogenous, in contrast to what was previously reported for other families such as Rutaceae, where they are reported as lysigenous. In Asteraceae, canals originate from cells of the procambium while cavities originate from cells of the ground meristem. The structural and developmental similarities between both types of secretory structures allow us to infer that they have a close evolutionary origin. Canals and secretory cavities in Asteraceae can be differentiated based on the number of strata of secretory epithelium and sheath, the modifications of epidermal cells and mesophyll, and the type of promeristem that gives rise to them. Probably extravascular canals give rise to cavities in leaves of Asteraceae and probably in other plant families.