Efficient plant regeneration via meristematic nodule culture in Paeonia ostii ‘Feng Dan’

Tree peony (Paeonia sect. Moutan) is an economically important multipurpose woody plant in terms of its medical, ornamental and oil values, but its breeding and industrial development are severely limited due to inefficient traditional propagation methods and existing in vitro regeneration systems. Meristematic nodules (MNs) are an attractive alternative to solve this problem. This study first presented a protocol for in vitro regeneration of P. ostii ‘Feng Dan’ via MN culture with four consecutive steps, including embryogenic callus (EC) formation, MN induction and leaf cluster differentiation, shoot elongation, rooting and acclimatization. The highest EC induction rate (81.25%) was achieved when cotyledons were cultured on modified Murashige and Skoog (mMS) medium with 4.04 µM N-(2-chloro-4-pyridyl)-N-phenylurea (CPPU) + 5.37 µM α-naphthylacetic acid (NAA) for 30 days. The optimal MN induction rate (100%) and leaf cluster differentiation rate (45.83%) were obtained when ECs were cultured on modified woody plant medium (mWPM) supplemented with 2.02 µM CPPU + 2.27 µM thidiazuron (TDZ) for a subculture time of 10 days. The combination of 1.29 µM 6-benzyladenine (BA) + 0.58 µM gibberellin (GA3) yielded the best shoot elongation (13.40 shoots per nodule), rooting rate (43.33%) and consequently survival rate (45.83%). The study will be beneficial to the mass propagation, breeding and genetic improvement of tree peony.

Breadth First Search and Inference Methods Integration to satisfy table constraints

Within the Constraint Programming technology, so-called table constraints such as typical tables, compressed tables, smart tables, segmented tables, etc, are widely used. They can be used to represent any other types of constraints, and algorithms of the table constraint propagation (logical inference on constraints) allow eliminating a lot of "redundant" values from the domains of variables, while having low computational complexity. In the previous studies, the author proposed to divide smart tables into structures of C- and D-types. The generally accepted methodology for solving con-straint satisfaction problems is the combined application of constraint propagation methods and backtracking depth-first search methods. In the study, it is proposed to integrate breadth-first search methods and author`s method of table con-straint propagation. D-type smart tables are proposed to be represented as a join of several orthogonalized C-type smart tables. The search step is to select a pair of C-type smart tables to be joined and then propagate the restrictions. To de-termine the order of joining orthogonalized smart tables at each step of the search, a specialized heuristic is used, which reduces the search space, taking into account further calculations. When the restrictions are extended, the acceleration of the computation process is achieved by applying the developed reduction rules for the case of C-type smart tables. The developed hybrid method allows one to find all solutions to the problems of satisfying constraints modeled using one or several D-type smart tables, without decomposing tabular constraints into elementary tuples.

In vitro Propagation of Banana (Musa paradisiaca L.) Plant Using Shoot Tip Explant

Banana is a fruit crop which has high demand in Ethiopia, but its production is constrained by lack of disease free planting material with conventional propagation methods. For shoot initiation, shoot tip explants were cultured on MS medium supplemented with 0.5, 1.0, 1.5 and 2.0 mg/L BAP. Similarly, MS medium supplemented with BAP at 1.0, 1.5, 2.0 mg/L in combination with IBA at 0.25 and 0.50 mg/L were used for shoot multiplication. Half- strength MS medium augmented with IBA at 1.0, 2.0, 3.0 and 4.0 mg/l were used for root induction. MS medium without PGRs were used as controls. Finally, hardening of the in vitro derived plantlets was carried out in green house both in the primary and secondary acclimatization stages. Results showed that the highest shoot initiation percent (93.40%), highest mean number of shoots per explant (4.67) and lesser day for shoot induction (11.00) were observed in explant cultured on MS + 1.0 mg/L BAP. With shoot multiplication, highest shooting percent (92.60%), maximum number of shoots (7.67) and highest shoot length (5.27 cm) were recorded on MS + 1.5 mg/L BAP + 0.5 mg/L IBA. The highest rooting percent (93.40%), maximum root number per shoot (7.67) and highest root length (11.00 cm) were found on a half strength MS medium + 2.0 mg/L IBA. The survival rate of plantlets were 96.00% in coco peat substrate in primary acclimatization and 97.92% in forest soil, sand and manure substrates mixed at 3:2:1 ratio in secondary acclimatization. Overall, the result showed that the PGRs type, concentrations and combinations used are effective for mass propagation of banana variety studied in this experiment.

SARS-CoV-2 detection in multi-sample pools in a real pandemic scenario: a screening strategy of choice for active surveillance

Background The current COVID-19 pandemic has overloaded the diagnostic capacity of laboratories by the gold standard method rRT-PCR. This disease has a high spread rate and almost a quarter of infected individuals never develop symptoms. In this scenario, active surveillance is crucial to stop the virus propagation. Methods Between July 2020 and April 2021, 11580 oropharyngeal swab samples collected in closed and semi-closed institutions were processed for SARS-CoV-2 detection in pools, implementing this strategy for the first time in Cordoba, Argentina. Five-sample pools were constituted before nucleic acid extraction and amplification by rRT-PCR. Comparative analysis of cycle threshold (Ct) values from positive pools and individual samples along with a cost-benefit report of the whole performance of the results was performed. Results From 2314 5-sample pools tested, 158 were classified as positive (6.8%), 2024 as negative (87.5%), and 132 were categorized as indeterminate (5.7%). The Ct value shift due to sample dilution showed an increase in Ct of 2.6 ±1.53 cycles for N gene and 2.6 ±1.78 for ORF1ab gene. Overall, 290 pools were disassembled and 1450 swabs were analyzed individually. This strategy allowed correctly identifying 99.8% of the samples as positive (7.6%) or negative (92.2%), avoiding the execution of 7,806 rRT-PCR reactions which represents a cost saving of 67.5%. Conclusion This study demonstrates the feasibility of pooling samples to increase the number of tests performed, helping to maximize molecular diagnostic resources and reducing the work overload of specialized personnel during active surveillance of the COVID-19 pandemic.

Propagation of SARS-CoV-2 in Calu-3 Cells to Eliminate Mutations in the Furin Cleavage Site of Spike

SARS-CoV-2 pathogenesis, vaccine, and therapeutic studies rely on the use of animals challenged with highly pathogenic virus stocks produced in cell cultures. Ideally, these virus stocks should be genetically and functionally similar to the original clinical isolate, retaining wild-type properties to be reliably used in animal model studies. It is well-established that SARS-CoV-2 isolates serially passaged on Vero cell lines accumulate mutations and deletions in the furin cleavage site; however, these can be eliminated when passaged on Calu-3 lung epithelial cell lines, as presented in this study. As numerous stocks of SARS-CoV-2 variants of concern are being grown in cell cultures with the intent for use in animal models, it is essential that propagation methods generate virus stocks that are pathogenic in vivo. Here, we found that the propagation of a B.1.351 SARS-CoV-2 stock on Calu-3 cells eliminated viruses that previously accumulated mutations in the furin cleavage site. Notably, there were alternative variants that accumulated at the same nucleotide positions in virus populations grown on Calu-3 cells at multiple independent facilities. When a Calu-3-derived B.1.351 virus stock was used to infect hamsters, the virus remained pathogenic and the Calu-3-specific variants persisted in the population. These results suggest that Calu-3-derived virus stocks are pathogenic but care should still be taken to evaluate virus stocks for newly arising mutations during propagation.

Review on regeneration status of Betulautilis D. Don: A critically endangered multipurpose timber line species in Indian Himalayan region

The Himalayan birch (Betulautilis D. Don), also known as Bhojpatra in India, is one of the Himalayan region's most important ethnobotanicaltreelinespecies. It aids in the preservation of the Himalaya's fragile environment by preventing soil erosion and conserving the rest of the flora and wildlife below the treelinezone.Betulautilis has been identified for medical (anticancer, anti-HIV, antimicrobial, antioxidant, and anti-inflammatory) and ethno botanical relevance by several ethnic and non-ethnic communities living in the Himalaya and elsewhere, in addition to several ecological benefits.The bark of the Betula tree has long been used to write old manuscripts.It may also be used as a packing material, is waterproof, can be used to roof dwellings, umbrellas, and other items.The historical usage of B. utilis, as well as recent overharvesting to suit community and commercial demands, have put strain on the species natural populations. B. utilis faces numerous threats, including overharvesting, deforestation, erosion, grazing, global warming, and disease attack.Thus, it has been categorized as Critically Endangeredspecies.The main problem of the mountain forestsislack of adequateregenerationprocess. Very little information on population dynamics, regeneration, and physiology and seed germination is available from different parts of the country but no any systematic study has been done so far on multipurpose timberline tree species of Indian Himalayan Region. As a result, it's critical to keep an eye on these sensitive places and keystone species for future changes caused by climate or anthropogenic pressure, especially in locations where baseline data is scarce. The ease and suitability of propagation methods for this species is also not well documented in the literature. With these limitations in mind, the current study aims to document the status of Betulautilis regeneration in the Indian Himalayan region.

Response of Growing Media and IBA Application under Different Weather Conditions on Growth of Pomegranate (Punica granatum L.) Cuttings

Pomegranate (Punica granatum L.) is an important commercial horticultural crop. The cultivation of this crop is increasing day by day. Mainly due to its survival nature, particularly in dry or less water available areas. Its propagation is possible by using seed but vegetative propagation methods are very popular. Even commercial propagation of pomegranate is done by cuttings. To fulfill the rising demand for high-quality plant material, easy, fast, reliable, economical multiplications are required, and under such circumstances, cuttings are the best-suited material. This method of propagation can further be improved by the use of optimum growing media and application of various plant growth regulators Indole Butyric acid and its derivations. Moreover, the success of propagation depends on prevailing weather conditions and the time of planting. Perlite + vermiculite and a combination of vermiculite + coco peat in equal proportions, quick dip application of 2500 ppm IBA, and planting in the spring season are considered ideal for fast and economical multiplication of pomegranate cuttings. Humid weather conditions during the spring season exhibit a good possibility of rooting and survival of the same. Therefore, the main aim of this review article is to collect/compile the information regarding the effect of growing media and applications of IBA under different weather regimes over previous years along with recent happenings.

Development of adaptive technology for cultivation and processing of rosebay willow-herb (Chamaenérionangustifolium)

The propagation methods of rosebay willow-herb were studied on the basis of theoretical and experimental studies, the optimal size of the feeding area of one plant in a field was described and established. The efficiency of cultivating these plants depending on the time of sowing in winter greenhouses and the field planting scheme was determined, scientific and practical justification of the feasibility of cultivating rosebay willow-herb as a raw material for the processing industry in the North-Eastern part of Tambov Region was given in order to obtain dry vegetable concentrate for the production of soft drinks, syrups, natural additives for functional enrichment of food products. A non-waste concentrate production technology was developed and implemented using gentle modes and intensive processes, such as two-stage vacuum-pulse drying, vacuum extraction.