Search Results (260)

Catalpa bungei C.A.Mey is an economically significant deciduous tree valued for timber production and landscaping applications. An efficient regeneration system is crucial for clonal propagation and serves as a foundation for future molecular breeding in C. bungei. This study established two in vitro regeneration pathways—indirect somatic embryogenesis and shoot organogenesis utilizing mature zygotic embryos as explants. Primary callus was induced from cotyledon, hypocotyl, and plumule explants. A high frequency (45.73%) of yellow-green compact callus was achieved on De-Klerk and Walton (DKW) medium supplemented with 2.0 mg/L 6-BA, 1.0 mg/L zeatin (ZT), and 0.1 mg/L NAA. Subsequent transfer to 1.5× Murashige and Skoog (MS) medium containing 1.5 mg/L 6-BA, 0.2 mg/L ZT, and 0.1 mg/L NAA yielded the highest embryogenic callus induction rate (16.67%). Embryogenic callus demonstrated bipotent potential, generating both adventitious shoots and somatic embryos under specific hormonal conditions. Histological analyses confirmed the typical developmental stages of somatic embryos, from globular to cotyledonary forms, validating the embryogenic origin of regenerated structures. Furthermore, hormone or osmotic additives such as abscisic acid (ABA), Phytagel, and polyethylene glycol 4000 (PEG4000) significantly enhanced somatic embryo induction, with Phytagel at 5.0 g/L achieving the highest rate (76.31%). For shoot organogenesis, the optimal hormonal combination of the 0.6 mg/L 6-BA, 0.4 mg/L KT, and 0.15 mg/L NAA achieved the highest bud induction rate (88.89%) and produced an average of 4.07 adventitious buds per explant. This study presents an efficient regeneration system for C. bungei, providing a practical platform for large-scale propagation and basis for biotechnological applications in woody plants. Full article

This study established an efficient in vitro regeneration system for Tibouchina granulosato (Desr.) Cogn. petiolated leaves to address the low propagation efficiency and propagatable germplasm shortages. The results revealed that the Murashige and Skoog (MS) medium supplemented with 1.1 mg/L of Zeatin (ZT) and 0.2 mg/L of 1-naphthyl acetic acid (NAA) was the optimal formulation for callus induction, yielding callus induction of 89.59%. For adventitious bud induction, the combination of 2.0 mg/L of 6-benzyladenine (BA) and 0.4 mg/L of NAA proved most effective, achieving an induction rate of 83.33%. Additionally, the adventitious shoots exhibited remarkable elongation when cultured in a medium containing 0.2 mg/L of BA and 0.04 mg/L of NAA. All explants rooted when treated with 0.5 mg/l NAA, inducing a mean number of 6.90 roots per plant and a survival percentage of 91.00%. This study provided technical support for the promotion of superior varieties and genetic improvement of Tibouchina granulosa. Full article

Agrobacterium-mediated transformation systems are extensively applied in japonica rice varieties. However, the adaptability of local rice varieties to existing transformation systems remains limited, owing to their complex genotypes, posing a substantial challenge to transformation. In this study, four local rice varieties were selected to optimize the effects of different culture media on callus induction, browning resistance, contamination resistance, callus tolerance, differentiation, regeneration, and root development, and then two varieties were selected to improve plant architecture and tiller development by CRISPR/Cas9-mediated gene editing, based on constructive transformation systems. The goal was to enhance the transformation efficiency of local varieties and innovate germplasms. The results demonstrated that japonica rice varieties XG293 and WD68 exhibited higher induction rates under the treatment of 2 mg/L 2,4-D (2,4-Dichlorophenoxyacetic acid) + 1 mg/L NAA (Naphthaleneacetic acid), whereas indica rice varieties H128 and E33 performed the best under 3 mg/L 2,4-D + 1 mg/L NAA. Severe browning in H128 was effectively mitigated by a carbon source of 20 g/L maltose supplemented with 40 mg/L ascorbic acid. Contamination after Agrobacterium infection was controlled by 300 mg/L Tmt (Timentin). Under a treatment of 200 µM/L acetosyringone +10 min infection duration, XG293 and WD68 exhibited higher callus tolerance, differentiation rates, and GUS staining rates, achieving transformation efficiencies of 43.24% and 52.38%, respectively. In contrast, H128 and E33 performed better under the treatment of 200 µM/L Acetosyringone + 5 min, with transformation efficiencies of 40.00% and 40.74%, respectively. The mutants after OsCCD7 gene editing in WD68 and H128 displayed a dwarfness of plant height, a significant increase in tiller numbers, and compact architecture. These findings demonstrate that an optimized combination of plant growth regulators and infection durations effectively improves transformation efficiency for local varieties, and the OsCCD7 gene regulates plant architecture and tiller development with variable effects, depending on the rice complex genotypes. This study provides a theoretical basis for the efficient transformation of local rice varieties and germplasm innovation. Full article

Cacao genotypes propagation through plant tissue culture represents a strategic approach for establishing a core collection of elite plants to be used as a donor material source, necessary for increasing new planting areas of cacao. This study aimed to evaluate somatic embryo regeneration in ten native fine-aroma cacao genotypes (INDES-06, INDES-11, INDES-14, INDES-32, INDES-52, INDES-53, INDES-63, INDES-64, INDES-66, INDES-70) from the INDES-CES germplasm collection, under in vitro conditions using culture medium supplemented with different concentrations of Thidiazuron (0, 10, and 20 nM). Our results showed an average of 20 and 100% of callogenesis in all genotypes evaluated, but the callus development did not appear after early stages of its induction; however, primary somatic embryos were observed after 42 days after TDZ treatment in the INDES-52, INDES-53, INDES-64, INDES-66, INDES-70 genotypes. The INDES-52 genotype was more responsive to under 20 nM of TDZ, generating an average of 17 embryos per explant. This study contributes to the adaptation and establishment of a protocol for somatic embryo regeneration of fine-flavor cacao genotypes. Full article

Roses are one of the most essential ornamental flowers in the world. At present, traditional techniques such as cross breeding are mainly used in rose breeding. The inefficiency of the in vitro regeneration system has become the limiting step for the innovation and genetic improvement of rose germplasm resources. A tissue culture rapid propagation system of Rosa ‘Pompon Veranda’ was established using the stem segments with shoots as the initial experimental material. The results showed that the best disinfection method was to soak the explants in 75% ethanol for 1 min, and then soak them in 15% sodium hypochlorite solution for 15 min. The contamination rate was only about 6%. The best rooting medium for tissue culture seedlings was 1/2MS with 0.1 mg∙L⁻¹ NAA, and the rooting rate can reach around 95%. On this basis, calluses were induced by using leaflets of tissue-cultured seedlings as explants. The results showed that the optimal medium for inducing callus tissue was MS + 5.0 mg∙L⁻¹ 2,4-D, with an induction rate of 100%. The calluses were cultured in the medium of MS with 0.01 mg∙L⁻¹ NAA, 1.5 mg∙L⁻¹ TDZ and 0.1 mg∙L⁻¹ GA₃ for 12 days in the dark and then transferred to light conditions. The differentiation rate of callus was 10.87%. On the medium of MS with 0.5 mg∙L⁻¹ 6-BA, 0.004 mg∙L⁻¹ NAA and 0.1 mg∙L⁻¹ GA₃, the shoots could regenerate into whole plants. This study has established an in vitro regeneration system of R. ‘Pompon Veranda’, which is a key perquisite for the subsequent establishment of its genetic transformation system. Moreover, this method will also be an important reference for studies on quality traits such as floral scent and prickles of Rosa plants. Full article

Cinnamomum camphora is an ecologically and economically significant species, highly valued for its essential oil production and environmental benefits. Although a tissue culture system has been established for C. camphora, large-scale propagation remains limited due to the inconsistent formation of adventitious roots (ARs). This study investigated AR formation from callus tissue, focusing on associated physiological changes and gene expression dynamics. During AR induction, contents of soluble sugars and proteins decreased, alongside reduced activities of antioxidant enzymes, including superoxide dismutase (SOD), peroxidase (POD), and polyphenol oxidase (PPO). Levels of indole-3-acetic acid (IAA) and abscisic acid (ABA) decreased significantly throughout AR formation. Zeatin riboside (ZR) levels initially declined and then rose, whereas gibberellic acid (GA) levels displayed the opposite trend. Comparative transcriptomic and temporal expression analyses identified differentially expressed genes (DEGs), which were grouped into four distinct expression patterns. KEGG pathway enrichment indicated that 67 DEGs are involved in plant hormone signaling pathways and that 38 DEGs are involved in the starch and sucrose metabolism pathway. Additionally, protein–protein interaction network (PPI) analysis revealed ten key regulatory genes, which are mainly involved in auxin, cytokinin, GA, ABA, and ethylene signaling pathways. The reliability of the transcriptome data was further validated by quantitative real-time PCR. Overall, this study provides new insights into the physiological and molecular mechanisms underlying AR formation in C. camphora and offers valuable guidance for optimizing tissue culture systems. Full article

Melastoma dodecandrum is primarily propagated through stem cuttings, which limits genetic variation and constrains breeding efforts. To overcome this limitation and facilitate molecular breeding, the establishment of a reliable and efficient regeneration system is essential. This study investigated the effects of plant growth regulators (PGRs) and culture media on the in vitro regeneration system of M. dodecandrum. The highest rate of callus induction (96.67%) was achieved when sterile leaf explants were cultured on Murashige and Skoog (MS) basal medium supplemented with 2.00 mg·L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.50 mg·L⁻¹ 6-benzylaminopurine (6-BA). For callus differentiation, the optimal formulation of MS + 2.0 mg·L⁻¹ 6-BA + 0.5 mg·L⁻¹ naphthylacetic acid (NAA) resulted in a differentiation frequency of 83.33%. The optimal PGR combinations for shoot proliferation were 1.5 mg·L⁻¹ 6-BA + 0.1 mg·L⁻¹ NAA and 0.5 mg·L⁻¹ 6-BA + 0.2 mg·L⁻¹ NAA. The optimal rooting media were MS medium supplemented with 0.1, 0.2, or 0.5 mg·L⁻¹ indole-3-butyric acid (IBA) or 1/2MS medium supplemented with 0.1 mg·L⁻¹ IBA. Additionally, this study investigated the dynamic changes in endogenous hormones during the regeneration process. The levels and ratios of hormones, including gibberellin (GA₃), abscisic acid (ABA), indole-3-acetic acid (IAA), and zeatin (ZT), collectively regulated the regeneration process. Elevated levels of ABA and GA₃ may promote callus initiation as well as the growth and development of adventitious roots during the early induction stage. Reduced levels of ABA and IAA favored callus differentiation into shoots, whereas elevated GA₃ levels facilitated proliferation of adventitious shoots. Throughout the regeneration process, fluctuations in ZT levels remained relatively stable. This study successfully established an in vitro regeneration system for M. dodecandrum using leaf explants, providing theoretical guidance and technical support for further molecular breeding efforts, genetic transformation, and industrial development. Full article

Bombax ceiba is an important medicinal and ornamental tree widely distributed in tropical and subtropical areas. However, its seeds lose viability rapidly after harvest, which has created hurdles in large-scale propagation. Here, we describe the development of a rapid and efficient de novo organogenesis system for Bombax ceiba, incorporating both indirect and direct regeneration pathways. The optimal basal medium used throughout the protocol was ½ MS supplemented with 30 g/L glucose, with all cultures maintained at 26–28 °C. For the indirect pathway, callus was induced from both ends of each hypocotyl on basal medium supplemented with 0.2 mg·L⁻¹ 2,4-dichlorophenoxyacetic acid (2,4-D) and 0.5 mg·L⁻¹ 6-Benzylaminopurine (6-BA) under dark conditions. The induced calluses were subsequently differentiated into adventitious shoots on basal media containing 0.5 mg·L⁻¹ Indole-3-butyric acid (IBA), 0.15 mg·L⁻¹ Kinetin (KIN), and 1 mg·L⁻¹ 6-BA under a 16 h photoperiod, resulting in a callus induction rate of 140% and a differentiation rate of 51%. For the direct regeneration pathway, shoot buds cultured on medium with 0.5 mg·L⁻¹ IBA and 1 mg·L⁻¹ 6-BA achieved a 100% sprouting rate with a regeneration coefficient of approximately 3.2. The regenerated adventitious shoots rooted successfully on medium supplemented with 0.5 mg·L⁻¹ Naphthylacetic acid (NAA) and were acclimatized under greenhouse conditions to produce viable plantlets. This regeneration system efficiently utilizes sterile seedling explants, is not limited by seasonal or environmental factors, and significantly improves the propagation efficiency of Bombax ceiba. These optimized micropropagation methods also provide a robust platform for future genetic transformation studies using hypocotyls and shoot buds as explants. Full article

Pinus elliottii, a key economic conifer in southern China, requires efficient propagation methods to meet demand for elite germplasm in resin and timber production. While somatic embryogenesis-based plant regeneration has been successfully achieved in Pinus elliottii, large-scale production remains challenging. Our results demonstrate that the genotype of Pinus elliottii significantly influences the induction rate of embryogenic callus. During somatic embryo maturation, the liquid–solid induction method increased the number of mature embryos by 25.85 times. Maturation efficiency was further enhanced by a 3-week pretreatment followed by the application of 9 mg/L ABA, 0.5 mg/L PSK, and 6 mg/L COS. Additionally, the incorporation of activated carbon significantly promoted both the maturation and germination of somatic embryos. In the somatic embryo maturation stage, 1 g/L activated carbon induced 288.67 mature embryos per gram of embryogenic callus, resulting in a total of 1452 embryos. During germination, the application of 4 g/L activated carbon achieved a germination rate of 63%, and the survival rate of somatic embryo-derived seedlings reached 85%. This study not only identifies the optimal conditions for somatic embryogenesis in Pinus elliottii but also establishes an efficient protocol for somatic embryo maturation induction, providing a crucial scientific foundation for the rapid propagation and seedling production of Pinus elliottii. Full article

Plant-specific WUSCHEL (WUS)-related homeobox (WOX) family of transcription factors are involved in apical meristem maintenance, embryogenesis, lateral organ development, and hormone signaling. Among the members of this family, WOX1 is known to play essential roles in many species. However, the function of the peony ‘Feng Dan’ (Paeonia ostii L.) WOX1 (PoWOX1) remains unknown. The initial bioinformatic analysis revealed that PoWOX1 belongs to the modern clade of the WOX gene family and has a highly conserved homeodomain (HD), the WUS motif, the STF-box, and the MAEWEST/WOX4-box. Subsequent heterologous overexpression in Arabidopsis thaliana revealed that PoWOX1 promotes root growth, early shoot initiation, and flowering. The root vascular tissues, especially the arrangement and size of xylem cells, were different between the PoWOX1-overexpressing transgenics and the wild-type plants, and the pericycle cells adjacent to the xylem divided more easily in the transgenics than in the wild type. Furthermore, under in vitro conditions, the transgenic leaf explants exhibited more callus induction and differentiation than the wild-type leaf explants. Thus, the study’s findings provide novel insights into the role of PoWOX1 in promoting root development and callus tissue induction and differentiation, serving as a reference for developing an efficient regeneration system for the peony. Full article

The rhizome of Atractylodes lancea (Thunb.) DC. is a traditional Chinese medicine used extensively owing to its antimicrobial properties. It is utilized to treat nyctalopia and problems related to the gastrointestinal tract. However, its yield is limited because of its endangered status, long growth period, and restricted reproductive ability. Ancillary approaches have not been established to ensure sustainable resource utilization by applying efficient plant regeneration technologies and producing bioactive metabolites via genome editing. This study reports the effects of explants, hormones, and culture conditions on embryogenic callus induction, plant regeneration, adventitious and hairy root cultivation, and essential oil production. Embryogenic calli were successfully induced in MS and 2.0 mg/L 2,4-D and 1.0 mg/L NAA and 1/2MS medium supplemented with 4.0 mg/L 6-BA and 0.4 mg/L NAA, which were optimal for callus differentiation. Maximum proliferation (12-fold) of cluster buds was observed with a select combination of hormones [NAA (0.2 mg/L) and 6-BA (2.0 mg/L)]. “Efficient plant regeneration and bioactive metabolite production” can provide technical support for the protection and sustainable utilization of A. lancea germplasm resources in terms of resource preservation and new variety breeding, natural product production, and industrial breeding of medicinal plants. Full article

Triadica sebifera, an economically and medicinally valuable tree species native to China, was investigated for its in vitro regeneration potential using leaf explants from nodal cuttings of young stems and sprouts. This study evaluated the effects of basal media, plant growth regulators (PGRs), explant sources, and incision methods on adventitious shoot induction, supplemented by histological analysis. The highest shoot regeneration frequency (98.89%) and maximum shoot number (72) were achieved via direct organogenesis using sucker-derived nodal cuttings cultured on MS medium with 2 mg/L 6- benzyladenine (6-BA), 0.3 mg/L kinetin (KT), and 0.2 mg/L α-naphthaleneacetic acid (NAA). Under identical conditions, branch-derived explants showed lower regeneration (84.44%, 64 shoots). Transverse midvein incision proved most effective, with sucker-derived leaves exhibiting superior regeneration. Shoots elongated completely (100%) on Murashige and Skoog (MS) medium containing 0.3 mg/L 6-BA, 0.03 mg/L NAA, and activated charcoal. Rooting was optimal on MS medium with 0.3 mg/L indole-3-butyric acid (IBA), yielding a 98% acclimatization survival rate. Histological analysis revealed de novo meristem formation from parenchyma cells, confirming direct organogenesis without callus intermediation, further validating the enhanced regenerative capacity of sprout-derived explants. This efficient in vitro regeneration system provides a foundation for large-scale propagation and germplasm conservation of T. sebifera, while offering insights for woody plant regeneration studies. Full article

Tree peony is well-known for its ornamental value, medicine function, oil, and edible use. However, the difficulty in propagating tree peony impedes its cultivation and industrial advancement. Softwood cutting is an effective method to promote the propagation of tree peony. This research investigated the effects of several factors (cultivar, cutting phenological stage, auxin type, polyamine, and substrate) on the rooting of softwood cutting in tree peony. The results showed that rooting ability varied with cultivars and cutting phenological stages, with the highest rooting rates being for ‘High noon’ and ‘Jinghua Qingxue’ during the vigorous growth stage, reaching 50% and 53.33%, respectively. IBA 2000 mg·L⁻¹ was optimal for rooting in ‘High noon’ cuttings, with the maximum root number (5.67) and root length (6.3 cm). Putrescine of 1.0 mM could significantly improve the rooting rate and rooting quality of ‘Jinghua Qingxue’ cuttings, which had the highest rooting rate of 54.17% in the cocopeat/perlite substrate (v:v 1:1). Anatomical observation showed that most adventitious roots were generated from callus meristem nodules differentiated from cortical parenchyma cells while a few came from stem bark, as well as integrated root induction. This study is an innovation in and supplement to tree peony propagation research, and a propagation protocol was primarily established for softwood cuttings in tree peony. Full article

Callus induction is one of the most important techniques in plant-based industries. Important features in the use of callus induction are the maintenance of pluripotency and the proliferation of cells. Although the importance of callus induction is also understood in ginseng, there are no studies on the genetic modules associated with callus induction and growth regulation. Panax ginseng embryo tissue was wounded and cultured in callus-inducing media, and its time-course physiology was observed. Time-course callus samples were collected for total RNA extraction and RNA-Seq analysis using the Illumina HiSeq X Ten platform. P. ginseng embryo tissue was wounded and treated with varying amounts of gamma radiation in callus-inducing media, and samples were also collected for total RNA extraction and RNA-Seq analysis. A combinatory analysis of various network analyses was used to reveal the regulatory network underlying callus development. We were able to determine the time-course physiology of callus development and the dose-dependent effect of gamma radiation on callus development. Network analysis revealed two networks correlated with callus induction and two networks correlated with callus growth. Our research provides a regulatory network illustrating how callus is induced and growth is regulated in P. ginseng. This result would be helpful in the development of a cell culture system or clonal propagation protocol in P. ginseng. Full article

Tea plants (Camellia sinensis) are among the world’s most significant economic tree species. Tissue culture serves as a crucial method in commercial breeding by facilitating the rapid propagation of valuable genotypes and the generation of disease-free clones. However, callus browning represents a prevalent challenge in tea plant tissue culture, and may adversely affect explant growth and development. Our research demonstrates that although anti-browning agents can effectively suppress browning, they induce distinct color changes in the callus. These color variations could significantly influence callus induction and subsequent growth patterns. In this study, callus tissues from C. sinensis var. Assamica cv. Mengku were employed as experimental materials and treated with three commonly used anti-browning agents: ascorbic acid (VC), activated carbon (AC), and polyvinylpyrrolidone (PVP). The results demonstrated that while these three reagents effectively inhibited browning, they also induced distinct color changes in the explants, which appeared red, green, and white, respectively. Furthermore, this study investigated the molecular mechanisms underlying callus color changes using transcriptomic and metabolomic approaches. Based on transcriptome analysis, it was revealed that photosynthesis and flavonoid biosynthesis pathways were significantly enriched. Metabolome analysis identified 14 phenolic acids, which exhibited significant variation in accumulation across calluses of different colors. The differential expression of genes involved in flavonoid biosynthesis pathways, coupled with the distinct accumulation patterns of metabolites, can effectively alleviate photooxidative damage and enhance the resistance of callus to browning. AC activates the photosynthesis of callus by regulating carbon source allocation and upregulating the expression of key genes in the psa, psb, and pet families within the photosynthetic system. This process promotes chlorophyll biosynthesis, thereby enabling the callus to grow green, while VC activates the expression of key genes such as CHS, F3H, C4H, CYP75B1, and ANR in the flavonoid pathway, which are involved in the regulation of pigment synthesis in red callus. This study elucidated the molecular mechanisms underlying the effects of anti-browning agents on color variations in C. sinensis callus, thereby providing a robust theoretical foundation for optimization, the establishment of tea plant tissue culture systems, and enhancing cultivar quality. Full article