Protoplasma最新文献

In plant tissue culture, differences in endogenous levels of species-specific plant growth regulators (PGRs) may explain differences in regenerative capacity. In the case of polyamines (PAs), their dynamics and distribution may vary between species, genotypes, tissues, and developmental pathways, such as sexual reproduction and apomixis. In this study, for the first time, we aimed to assess the impact of varying endogenous PAs levels in seeds from distinct reproductive modes in Miconia spp. (Melastomataceae), on their in vitro regenerative capacity. We quantified the free PAs endogenous content in seeds of Miconia australis (obligate apomictic), Miconia hyemalis (facultative apomictic), and Miconia sellowiana (sexual) and evaluated their in vitro regenerative potential in WPM culture medium supplemented with a combination of 2,4-dichlorophenoxyacetic acid (2,4-D) and 6-benzylaminopurine (BAP). The morphogenic responses were characterized by light microscopy and scanning electron microscopy and discussed regarding the endogenous PAs profiles found. Seeds of M. sellowiana presented approximately eight times more putrescine than M. australis, which was associated with a higher percentage of regenerated calluses (76.67%) than M. australis (5.56%). On the other hand, spermine levels were significantly higher in M. australis. Spermine is indicated as an inhibitor of auxin-carrying gene expression, which may have contributed to its lower regenerative capacity under the tested conditions. These findings provide important insights into in vitro morphogenesis mechanisms in Miconia and highlight the significance of endogenous PA levels in plant regeneration. These discoveries can potentially optimize future regeneration protocols in Miconia, a plant group still underexplored in this area.

Soil salinization leads to a reduction in arable land area, which seriously endangers food security. Developing saline-alkali land has become a key measure to address the contradiction between population growth and limited arable land. Rice is the most important global food crop, feeding half of the world's population and making it a suitable choice for planting on saline-alkali lands. The traditional salt-alkali improvement method has several drawbacks. Currently, non-thermal plasma (NTP) technology is being increasingly applied in agriculture. However, there are few reports on the cultivation of salt/alkali-tolerant rice. Under alkaline stress, argon NTP treatment significantly increased the germination rate of Longdao 5 (LD5) rice seeds. In addition, at 15 kV and 120 s, NTP treatment significantly increased the activity of antioxidant enzymes such as catalase and SOD. NTP treatment induced changes in genes related to salt-alkali stress in rice seedlings, such as chitinase and xylanase inhibitor proteins, which increased the tolerance of the seeds to salt-alkali stress. This experiment has expanded the application scope of NTP in agriculture, providing a more cost-effective, less harmful, and faster method for developing salt-alkali-tolerant rice and laying a theoretical foundation for cultivating NTP-enhanced salt-alkali-tolerant rice.

Transient transformation is extremely useful for rapid in vivo assessment of gene function, especially for fruit-related genes. Grape berry, while an important fruit crop, is recalcitrant to transient transformation, due to the high turgor pressure in its mesocarp cells that limits the ability of Agrobacterium to penetrate into the tissue. It is urgent to establish a simple transient transformation system for rapid analysis of gene function. In this study, different injection methods, grape genotypes, and developmental stages were tested in order to develop a rapid and efficient Agrobacterium-mediated transient transformation methodology for grape berries. Two injection methods, namely punch injection and direct injection, were evaluated using the β-glucuronidase (GUS) gene and by x-gluc tissue staining and 4-methylumbelliferyl-β-D-glucuronide fluorescence analysis. The results indicated that there were no significant differences on transformation effects between the two methods, but the latter was more suitable because of its simplicity and convenience. Six grape cultivars ('Hanxiangmi', 'Moldova', 'Zijixin', 'Jumeigui', 'Shine-Muscat', and 'A17') were tested for transient transformation. 'Hanxiangmi', 'Moldova', and 'Zijixin' grape berries were not suitable for agroinfiltration due to frequently fruit cracking, browning, and formation of scar skin. The fruit integrity rates of 'Jumeigui', 'Shine-Muscat', and 'A17' berries were all above 80%, and GUS activity was detected in the berries of the three cultivars 3-14 days after injection with the Agrobacterium culture, while higher GUS activities were observed in the 'Jumeigui' berries. The levels of GUS activity in injected berries at 7-8 weeks after full blooming (WAFB) were more than twice at 6 WAFB. In subsequent assays, the over-expression of MYB transcription factor VvMYB44 via transient transformation accelerated the anthocyanin accumulation and fruit coloring through raising the expression levels of VvLAR1, VvUFGT, VvLDOX, VvANS, and VvDFR, which verified the effectiveness of this transformation system. These experiments finally identified the reliable grape cultivars and suitable operational approach for transient transformation and further indicated that this Agrobacterium-mediated transient transformation system was efficient and suitable for the elucidation of gene function in grape berries.

Drought stress adversely affects growth, development, productivity, and fiber quality of cotton (Gossypium hirsutum L). Breeding strategies to enhance drought tolerance require an improved knowledge of plant drought responses necessitating proper identification of drought-tolerant genotypes of crops, including cotton. The objective of this study was to classify the selected cotton genotypes for their drought tolerance ability based on morpho-physio-biochemical traits using Hierarchical Ward's cluster analysis. Five genotypes of cotton (Takfa 3, Takfa 6, Takfa 7, Takfa 84-4, and Takfa 86-5) were selected as plant materials, and were grown under well-watered (WW; 98 ± 2% field capacity) and water-deficit (WD; 50 ± 2% field capacity) conditions for 16 days during the flower initiation stage. Data on morpho-physio-biochemical parameters and gene expression levels for these parameters were collected, and subsequently genotypes were classified either as a drought tolerant or drought susceptible one. Upregulation of GhPRP (proline-rich protein), GhP5CS (Δ¹-pyrroline-5-carboxylate synthetase), and GhP5CR (Δ¹-pyrroline-5-carboxylate reductase) in relation to free proline enrichment was observed in Takfa 3 genotype under WD condition. An accumulation of free proline, total soluble sugar, and potassium in plants under WD conditions was detected, which played a key role as major osmolytes controlling cellular osmotic potential. Magnesium and calcium concentrations were also enriched in leaves under WD conditions, functioning as essential elements and regulating photosynthetic abilities. Leaf greenness, net photosynthetic rate, stomatal conductance, and transpiration rate were also declined under WD conditions, leading to growth retardation, especially aboveground traits of Takfa 6, Takfa 7, Takfa 84-4, and Takfa 86-5 genotypes. An increase in leaf temperature (1.1 - 4.0 °C) and crop water stress index (CWSI > 0.75) in relation to stomatal closure and reduced transpiration rate was recorded in cotton genotypes under WD conditions compared with WW conditions. Based on the increase of free proline, soluble sugar, leaf temperature, and CWSI, as well as the decrease of aboveground growth traits and physiological attributes, five genotypes were categorized into two cluster groups: drought tolerant (Takfa 3) and drought susceptible (Takfa 6, Takfa 7, Takfa 84-4, and Takfa 86-5). The identified drought-tolerant cotton genotype, namely, Takfa 3, may be grown in areas experiencing drought conditions. It is recommended to further validate the yield traits of Takfa 3 under rainfed field conditions in drought-prone environments.

Crocus sativus is a valuable plant due to the presence of apocarotenoids in its stigma. Considerable work has been done in the past to understand the apocarotenoid biosynthetic pathway in saffron. However, the reports on understanding the regulation of flowering at the post-transcriptional level are meagre. The study aimed to discover the candidate miRNAs, target genes, transcription factors (TFs), and apocarotenoid biosynthetic pathway genes associated with the regulation and transition of flowering in C. sativus. In the present investigation, miRNA profiling was performed in flowering and non-flowering corms of saffron, along with expression analysis of apocarotenoid genes and transcription factors involved in the synthesis of secondary metabolites. Significant modulation in the expression of miR156, miR159, miR166, miR172, miR395, miR396, miR399, and miR408 gene families was observed. We obtained 36 known miRNAs (26 in flowering and 10 in non-flowering) and 64 novel miRNAs (40 in flowering and 24 in non-flowering) unique to specific tissues in our analysis. TFs, including CsMADS and CsMYb, showed significant modulation in expression in flowering tissue, followed by CsHB. Additionally, the miRNAs were predicted to be involved in carbohydrate metabolism, phytohormone signalling, regulation of flower development, and response to stress, cold, and defence. The comprehensive study has enhanced our understanding of the regulatory machinery comprising factors like phytohormones, abiotic stress, apocarotenoid genes, transcription factors, and miRNAs responsible for the synthesis of apocarotenoids and developmental processes during and after flowering.

The Pfaffia glomerata, a plant popularly called Brazilian ginseng, is widely used in Brazil for the treatment of various pathologies, including those associated with the Central Nervous System. 20-hydroxyecdysone (20E), a phytosteroid present in this plant, can promote adaptogenic effects in the organism, providing greater body resistance to stressors. This study aimed to evaluate the phytochemical composition and the anticholinesterase, antioxidant, and antiglycation effects of extracts and fractions of aerial parts and roots of P. glomerata, also analyzing their possible cytotoxic effects. The fractions were obtained by partitioning methanol extracts from the aerial part and roots of P. glomerata with hexane, dichloromethane, ethyl acetate, n-butanol, and water. The samples were initially tested in anticholinesterase, antioxidant, and antiglycation assays, and the most promising samples were submitted for cytotoxicity and chromatographic analyses. Mass spectrometry and chromatography methods revealed that 20E was the main compound in the dichloromethane fractions, there being 35% more 20E in the aerial part (APD) than in the roots (RD). Added to the higher concentration of 20E, the APD fraction also presented more promising results than the RD fraction in anticholinesterase and antioxidant analyses, indicating that their effects may be related to the concentration of 20E. These same fractions showed no hemolytic effects but were cytotoxic in high concentrations. These new findings contribute to scientific information about P. glomerata and open more perspectives for the understanding of its therapeutic properties, allowing the association of biological activity with the presence of 20E.

A transcription factor in plants encodes SQUAMOSA promoter binding protein-like (SPL) serves a broad spectrum of important roles for the plant, like, growth, flowering, and signal transduction. A gene family that encodes SPL proteins is documented in various model plant species, including Arabidopsis thaliana and Oryza sativa. Chickpea (Cicer arietinum), a leguminous crop, has not been thoroughly explored with regard to the SPL protein-encoding gene family. Chickpea SPL family genes were located and characterized computationally using a genomic database. Gene data of chickpea were obtained from the phytozome repository and was examined using bioinformatics methods. For investigating the possible roles of SPLs in chickpea, genome-wide characterization, expression, as well as structural analyses of this SPL gene family were performed. Cicer arietinum genome had 19 SPL genes, whereas, according to phylogenetic analysis, the SPLs in chickpea are segregated among four categories: Group-I has 2 introns, Group-II and IV have 1-2 introns (except CaSPL13 and CaSPL15 having 3 introns), and Group-III has 9 introns (except CaSPL1 and CaSPL11 with 1 and 8 introns, respectively). The SBP domain revealed that SPL proteins featured two zinc-binding sites, i.e., C3H and C2HC and one nuclear localization signal. All CaSPL proteins are found to contain highly conserved motifs, i.e., Motifs 1, 2, and 4, except CaSPL10 in which Motifs 1 and 4 were absent. Following analysis, it was found that Motifs 1 and 2 of the chickpea SBP domain are Zinc finger motifs, and Motif 4 includes a nuclear localization signal. All pairs of CaSPL paralogs developed by purifying selection. The CaSPL promoter investigation discovered cis-elements that are responsive to stress, light, and phytohormones. Examination of their expression patterns highlighted major CaSPLs to be evinced primarily among younger pods and flowers. Indicating their involvement in the plant's growth as well as development, along with their capacity to react as per different situations by handling the regulation of target gene's expression, several CaSPL genes are also expressed under certain stress conditions, namely, cold, salt, and drought. The majority of the CaSPL genes are widely expressed and play crucial roles in terms of the plant's growth, development, and responses to the environmental-stress conditions. Our work provides extensive insight into the gene family CaSPL, which might facilitate further studies related to the evolution and functions of the SPL genes for chickpea and other plant species.

The investigation was carried out to evaluate the net effect of limited irrigation on the antioxidant status of pollens, flag leaves, and developing grains of wild and inbred maize lines. Teosinte pollens showed the highest activities of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR), glutathione-s-transferase (GST), and peroxidase (POX) under stressful conditions while LM 11 showed a significant decrease in APX, CAT, GR, and GST activities. Limited irrigations increased the contents of superoxide and malondialdehyde (MDA) to maximum levels in LM 11 leaves. The pollens, leaves, and developing grains of teosinte had the highest content of total phenols. Proline was maximum in the developing grains of teosinte and CML 32 while lowest in those of LM 11. Principal component analysis showed that LM 11 genotype and the respective antioxidant enzymes were in completely opposite quadrants. Chord analysis showed that CAT activity and total phenol content in pollens, leaves, and developing grains contributed towards most of the variations observed in teosinte and might be responsible for managing the yield attributes of genotype during stress conditions. The pollens and leaves of teosinte, with significant SOD activity, further helped in optimizing plant yield, under stressful conditions. CML 32 occupied intermediate position owing to the unaffected activities of most of the antioxidant enzymes and high content of antioxidants in its tissues. It may be concluded that the overall antioxidant status of tissues decides the tolerance behavior of plants.