Search Results (10)

Cassava mosaic disease (CMD) is caused by begomoviruses and can result in yield losses of up to 90% in susceptible varieties. Using disease-free planting material from in vitro cultures is one of the most effective ways of controlling this disease. A CMD epidemiological assessment was conducted in fields established with disease-free plantlets in Bouaké, Dabou, and Man, selected for their contrasting agroecological and CMD prevalence conditions. Virus and whitefly species characterisation was performed using PCR and sequencing. CMD incidence and severity were lowest at the Man site and highest at the Dabou site. Although whitefly abundance was relatively low at the Man and Bouaké sites compared to the Dabou site, they were a significant factor in the spread of the disease. While all resistant varieties remained asymptomatic, susceptible and tolerant varieties became infected, and some tolerant varieties were able to recover from the disease. Molecular analyses revealed the presence of two viral species: Begomovirus manihotis (ACMV) and Begomovirus manihotiscameroonense (EACMCMV). No viral infection was detected 4 weeks after planting (WAP). Cases of single infection and double infection were observed at 12 and 20 WAP. Also, no double infections were found at the Man site, in contrast to the Bouaké site (12 WAP: 2.36%) and Dabou site (12 WAP: 2.59%; 20 WAP: 5.76%). EACMCMV was found in a single infection in Bouaké (12 WAP: 1.39%) and Man (20 WAP: 0.66%). The whitefly species Bemisia tabaci and Bemisia afer were most commonly found feeding on all cassava varieties. A high diversity of whitefly species was observed in Bouaké and Dabou compared to Man. Furthermore, the Bemisia tabaci species identified in this study was found to be able to transmit ACMV and EACMCMV viruses. These highlights would contribute to improving CMD management and control strategies. Full article

Potatoes, a vital global food crop, have shown remarkable adaptability, significantly contributing to food security. Technological advancements now enable their cultivation from soil-based systems to liquid synthetic nutrient media, even in artificial closed environments without natural light or fertile soil. This study examined the effects of Benzylaminopurine (BAP) and Kinetin (Kin) at concentrations ranging from 0 to 5 mg/L and sucrose concentrations ranging from 20 to 120 g/L on in vitro tuberization, focusing on microtuber size, weight, and tuberization rate. Nodal segments from virus-free ‘Red Scarlet’ in vitro potato plantlets were used as explants. These explants were cultured on Murashige and Skoog (MS) medium solidified with 0.5% agar. The study also compared minituber production efficiency under soil-based greenhouse and aeroponic conditions. The highest in vitro potato tuberization rate (90%) was achieved with 80 g/L sucrose and 3.0 mg/L BAP. After induction, virus-free microtubers were transferred to both greenhouse conditions and aeroponic systems for further assessment of minituber production and biochemical composition. These findings demonstrate the potential of aeroponics as a superior method for producing high-quality, pathogen-free minitubers. Aeroponics resulted in significantly higher minituber yields compared to soil-based greenhouse systems, offering a scalable and efficient solution for seed production. Full article

Sweet potato (Ipomoea batatas L. Lam.) is a major source of food in many parts of Ethiopia. In recent years, viral diseases have become the main threat to sweet potato production in Ethiopia. Previous virus survey studies carried out from 1986 to 2020 reported eight viruses infecting sweet potato in Ethiopia. Consequently, obtaining and multiplying virus-free planting materials have been difficult for farmers and commercial multipliers. This study was conducted to detect viruses infecting the five sweet potato varieties used as source plants and compare the virus elimination efficiency between meristem cultures from untreated and heat-treated mother plants and production of virus-free sweet-potato-planting materials. Seven common viruses were tested for, using grafting to Ipomoea setosa, enzyme-linked immunosorbent assay (ELISA) and reverse-transcription polymerase chain reaction (RT–PCR) before and after elimination procedures as screening and confirmatory methods. The sweet potato feathery mottle virus (SPFMV) elimination efficiencies of meristem cultures from untreated (grown at 25 ± 1 °C) and heat-treated (grown at 39 ± 1 °C) potted plants of sweet potato varieties were evaluated and compared. Sweet potato feathery mottle virus (SPFMV) was detected in 12 of the 15 source plants tested. Triple infections of SPFMV, sweet potato chlorotic stunt virus (SPCSV), and sweet potato virus C (SPVC) were detected in one of the fifteen plants. This study reports the detection of SPVC for the first time in sweet potato plants from Ethiopia. The cutting of meristems from heat-treated plants further increased the percentage of virus-free plantlets by ca 10% to ca 16%, depending on the plant variety. Elimination efficiency also seemed to vary among varieties: the greatest difference was observed for ‘Tola’, and the least difference was observed for ‘Guntute’. The present study provided protocols for detecting viruses and generating virus-free sweet-potato-planting materials in Ethiopia. Full article

The shoot apical meristem culture has been used widely to produce virus-free plantlets which have the advantages of strong disease resistance, high yield, and prosperous growth potential. However, this virus-free plant will be naturally reinfected in the field. The physiological and metabolic responses in the reinfected plant are still unknown. The flower of chrysanthemum ‘Hangju’ is a traditional medicine which is unique to China. In this study, we found that the virus-free ‘Hangju’ (VFH) was reinfected with chrysanthemum virus B/R in the field. However, the reinfected VFH (RVFH) exhibited an increased yield and medicinal components compared with virus-infected ‘Hangju’ (VIH). Comparative analysis of transcriptomes was performed to explore the molecular response mechanisms of the RVFH to CVB infection. A total of 6223 differentially expressed genes (DEGs) were identified in the RVFH vs. the VIH. KEGG enrichment and physiological analyses indicated that treatment with the virus-free technology significantly mitigated the plants’ lipid and galactose metabolic stress responses in the RVFH. Furthermore, GO enrichment showed that plant viral diseases affected salicylic acid (SA)-related processes in the RVFH. Specifically, we found that phenylalanine ammonia-lyase (PAL) genes played a major role in defense-related SA biosynthesis in ‘Hangju’. These findings provided new insights into the molecular mechanisms underlying plant virus–host interactions and have implications for developing strategies to improve plant resistance against viruses. Full article

Traditional gladiolus propagation methods are now supplemented with in vitro propagation to meet the demands of modern floriculture in terms of quick production of disease-free, quality planting material. Due to virus infections, vegetative propagation in gladiolus in the field is slow, and is a serious concern in the propagation of gladiolus. In vitro propagation provides an enormous increase in propagation rate and the ability to produce disease-free plant material. Numerous elements, including cultivars, explant type, size of explants, position of explants on medium, plant growth regulators and certain additives, incubation conditions, and sub-culturing time, all have a significant impact on in vitro clonal propagation of gladiolus plants as well as the development of in vitro cormel efficiency. There are certain obstacles and challenges that arise in the in vitro development of plants and the cormels of gladiolus. However, numerous studies and review reports on gladiolus for in vitro propagation have been reported, but very little is known about the factors influencing gladiolus’ in vitro effectiveness. In the present review, we focused on and analyzed research data accumulated over 50 years on diverse strategies for in vitro propagation such as direct, indirect organogenesis, and somatic embryogenesis, as well as various factors such as physical, nutritional, and hormonal influences on in vitro propagation, in vitro cormel formation efficiency, difficulties that arise, and new insights into in vitro development in gladiolus from the available literature worldwide. Future possibilities for further improvement in the in vitro propagation of ornamental gladiolus are also discussed. The current review provides insight into a comprehensive protocol for gladiolus in vitro propagation and emphasizes the importance of continuously advancing tissue culture techniques and factors influencing the in vitro efficiency towards improving in vitro plantlets and cormels in gladiolus (Gladiolus spp.). Full article

Potato virus Y (PVY) causes serious loss in the yield and quality of potatoes. The effect of chitosan nanoparticles (CS-NPs) on the regeneration response and production of PVY-free plants under in vitro conditions was studied. Murashige and Skoog (MS) medium supplemented with 0.1 mg L⁻¹ Gibberellic acid (GA₃), 0.1 mg L⁻¹ Naphthalene acetic acid (NAA) and 500 mg L⁻¹ malt extract was used for regeneration of plantlets from sprouts. Double Antibody Sandwich Enzyme-Linked Immunosorbent Assay (DAS-ELISA) and Reverse Transcript Polymerase Chain Reaction (RT-PCR) was used for virus indexing of the mother plant and in vitro-regenerated plantlets. Explants of PVY positive potato plants were cultured on same medium amended with 100, 200, 250, and 300 mg L⁻¹ of (CS-NPs). Shoot regeneration decreased from 100 to 200 mg L⁻¹ as the concentrations of antiviral (CS-NPs) up to 250 mg L⁻¹. It was decreased with the increase in the concentration of the antiviral (CS-NPs) up to 300 mg L⁻¹. Antiviral (CS-NPs) at the concentration of 250 mg L⁻¹ showed a positive effect on shoot regeneration. In vitro-regenerated plantlets were virus free and tested negative in both ELISA and RT-PCR. The level of 100 mg L⁻¹ of (CS_NPs) produced 38.8% PVY-free plants and 30.50% of cultures showed shoot regeneration. The level of 200 mg L⁻¹ of (CS-NPs) produced 49.6% PVY-free plants while 46.8% of cultures showed shoot regeneration. The level of 250 mg L⁻¹ of (CS-NPs) was the most effective and produced 100.0% PVY-free plants and 100.0% of cultures showed shoot regeneration. Histopathological changes simultaneously with elucidation of resistance and growth enhancement were evident in the treated plants with (CS-NPs) than those untreated control. In conclusion, (CS-NPs) treatment is an effective tool to produce PVY-free sprouts explants and has potential for producing virus-free planting material for the potato industry. Full article

Peach cultivars (’Elberta’, ‘Red Top’, and ’Dixie Red’) were studied for their in vitro adoptability and performance in producing virus-free plantlets. The thermotherapy method with increasing temperatures (25 °C to 37 °C) was applied for the elimination of famous peach infecting plum pox viruses (PPVs) and prunus necrotic ringspot virus (PNRSV), and the DS-ELISA test and RT-PCR technique were performed to confirm the production of virus-free microshoots. The application of 30 mg L⁻¹ of Fe-EDDHA treatment resulted in the best performance for culture establishment of all cultivars, where the best subsequent morphological performance in terms of branch and leaf numbers was recorded for the ’Dixie Red’ cultivar in MS medium, supplemented with 0.5 mgL⁻¹ of gibberellic acid (GA₃) and 0.5 mg L⁻¹ of 6-Benzylaminopurine (BAP). At the regeneration stage, the highest (26.96 mm) and lowest (18.43 mm) shoot lengths were obtained from the ’Dixie Red’ cultivar treated with GA₃ (2 mg L⁻¹) + thidiazuron (TDZ) (2.5 mg L⁻¹) and the ’Red Top’ cultivar treated with GA₃ (1 mg L⁻¹) + TDZ (1 mg L⁻¹), respectively. The leaf numbers were affected by the application of growth regulators, where the ’Elberta’ cultivar under GA₃ (2 mg L⁻¹) + TDZ (2.5 mg L⁻¹) treatment showed the highest numbers and the ’Red Top’ cultivar under GA₃ (1 mg L⁻¹) + TDZ (1 mg L⁻¹) showed the lowest mean values. The thermotherapy treatment and micropropagation of shoot tips resulted in 100% virus-free plantlets, as confirmed by both applied diagnostic methods. The result of the application of the rooting stage with growth regulators on ’Elberta’ plantlets showed the best performance (90%) in ½ MS medium supplemented with 0.5–1 mg L⁻¹ of IBA, which was significantly higher than the same treatment in MS medium. The obtained results should constitute the basis for further optimization of the multiplication and rooting of virus-free peach plantlets to be served for nurseries and planation orchards. Full article

This first-attempt study used microtome-based methods to generate a thin cell layer culture for the micropropagation of Phal. Hwafeng Redjewel × Phal. New Cinderella. Protocorms were embedded in various agarose concentrations (8–12%, w/v) and dried from 1 to 8 h before sectioning with a microtome. Optimal conditions for slicing sections of 100 to 300 μm were achieved when the protocorms were embedded at 10% (w/v) agarose and dried for 4 h under laminar flow, and the hardness of the agarose block under these conditions reached 641.8 ± 9.5 g·cm⁻². The sectioned protocorms that were cultured on an MS medium supplemented with 1.2 mg·L⁻¹ 6-benzylaminopurine and 0.1 mg·L⁻¹ α-naphthaleneacetic acid were capable of growth and differentiated through the neoformation of protocorm-like bodies (PLBs) and/or callus before subsequent regeneration into plantlets and development into healthy plants in a nursery environment. The results of this study demonstrate that microtome-based tTCL is a reliable and promising approach for mass propagation and possible virus-free propagation objectives for Phalaenopsis. Full article

Culinary rhubarb is a popular vegetable crop, valued for its long, thickened stalks, very rich in different natural bioactive ingredients. Tissue cultures are a useful tool for vegetative propagation of virus-free rhubarb plants and rapid multiplication of valuable selected genotypes. The aim of this study was to develop an effective method for in vitro propagation of selected genotypes of Polish rhubarb ‘Malinowy’ characterized by high yield and straight, thick and intensive red stalks. Identification and quantification of anthocyanins and soluble sugars by the HPLC method in shoot cultures and ex vitro established plantlets were also performed. Shoot cultures were established from axillary buds isolated from dormant, eight-year-old rhizomes. Effective shoot multiplication of rhubarb ‘Malinowy’ was obtained in the presence of 6.6 µM benzylaminopurine or 12.4 µM meta-topolin. Both cytokinins stimulated shoot formation in a manner that depended on sucrose concentration. Increasing the sucrose concentration from 59 to 175 mM decreased the production of shoots and outgrowth of leaves by 3-fold but enhanced shoot length, single shoot mass and callus formation at the base of shoots. This coincided with increased accumulation of soluble sugars (fructose, glucose) and anthocyanins-cyanidin-3-O-rutinoside (max. 208.2 mg·100 g⁻¹ DM) and cyanidin-3-O-glucoside (max. 47.7 mg·100 g⁻¹ DM). The highest rooting frequency (94.9%) and further successful ex vitro establishment (100%) were observed for shoots that were earlier rooted in vitro in the presence of 4.9 µM indole-3-butyric acid. Our results indicated that anthocyanin contents in leaf petioles were influenced by developmental stage. Under in vitro conditions, it is possible to elicit those pigments by sucrose at high concentration and meta-topolin. Full article

Plant regeneration and somatic embryogenesis through interspecific hybridization among different Carica species were studied for the development of a papaya ringspot virus-resistant variety. The maximum fruit sets were recorded from the cross of the native variety C. papaya cv. Shahi with the wild species C. cauliflora. The highest hybrid embryos were recorded at 90 days after pollination and the embryos were aborted at 150 days after pollination. The immature hybrid embryos were used for plant regeneration and somatic embryogenesis. The 90-day-old hybrid embryos from the cross of C. papaya cv. Shahi × C. cauliflora showed the highest percentage of germination, as well as plant regeneration on growth regulators free culture medium after 7 days pre-incubation on half-strength MS medium supplemented with 0.2 mg/L BAP, 0.5 mg/L NAA and 60 g/L sucrose. The 90-day-old hybrid embryos from the cross of C. papaya cv. Shahi × C. cauliflora produced maximum callus, as well as somatic embryos when cultured on half-strength MS medium containing 5 mg/L 2,4-D, 100 mg/L glutamine, 100 mg/L casein hydrolysate and 60 g/L sucrose. The somatic embryos were transferred into half-strength MS medium containing 0.5 mg/L BAP and 0.2 mg/L NAA and 60 g/L sucrose for maturation. The highest number of regenerated plants per hybrid embryo (10.33) was recorded from the cross of C. papaya cv. Shahi × C. cauliflora. Isoenzyme and dendrogram cluster analysis using UPGMA of the regenerated F₁ plantlets confirmed the presence of the hybrid plantlets. Full article