Endophytic contaminants are a common problem for the in vitro propagation of woody plants and have significant economic repercussions for the conservation of plant genetic resources and commercial micropropagation. In this study, first, the microbial contamination that appeared around the base of in vitro-grown apple shoots was identified as Bacillus megaterium. Then, plant preservative mixture (PPM^TM) was used as a bactericidal agent in plant tissue culture. Its efficacy for eradicating endophytic B. megaterium in in vitro cultures of apple was tested. In vitro-contaminated shoots were grown in tissue culture medium supplemented with 0.2% v/v PPM^TM for 12 weeks and then transferred to medium without any PPM^TM and cultured for 24 weeks. This study showed that PPM^TM is an effective agent for controlling the growth of B. megaterium. Our results highlight the species-specific response of apple shoots to PPM^TM. PPM^TM was effective in controlling endogenous microbial contaminations from apple varieties ‘Golden Delicious’, ‘Landsberger Renette’, ‘Suislepper’, and ‘Aport krovavo-krasnyi’; meanwhile, in ‘KG 7’ and ‘Gold Rush’, all the plants grown in the absence of PPM^TM were still bacterially contaminated, even though they were pre-treated for 12 weeks in PPM^TM-supplemented medium. These results therefore suggest the essentiality of further testing of extended incubation of PPM^TM in these cultivars that had outbreaks of bacterial contamination.

The aim of this paper was to study the effect of plant growth regulators on callus induction and in vitro morphogenesis using various explants of Paulownia tomentosa to develop an efficient plant regeneration protocol. Different plant organ sections (leaves, apical shoot tips, petals, nodes, and internodes) were cultured as explants to identify the best in vitro explants responsive to callus induction and plant regeneration. Explants were cultivated on MS media supplemented with different concentrations of plant growth regulators (TDZ (Thidiazuron), BAP (6-Benzylaminopurine), kinetin, and NAA (1-Naphthaleneacetic acid). It was discovered that the addition of TDZ and NAA stimulated the induction of somatic embryogenesis. It was discovered that the MS medium with the combination of plant growth regulators BAP (35.5 µM) and NAA (5.4 µM) with the addition of 30.0 g/L maltose, 500.0 mg/L casein hydrolysate, and 250.0 mg/L L-proline was optimal for callus induction and multiple plant regeneration. The study of the regenerative capacity of various explants of Paulownia tomentosa in vitro showed that plant regeneration depends on the type of explant, and occurs in both ways, indirectly, through the formation of callus tissues and directly on the explant, without callus formation. As a result of this study, the efficient reproducible protocol of embryogenic callus formation and multiple shoot induction in vitro of Paulownia tomentosa was developed. This system provides a clear increase in the frequency of plant regeneration from 36.3 ± 3.4% to 38.6 ± 2.3% per embryogenic callus from leaves and apical shoot tips, respectively.

The ongoing genetic erosion of natural Prunus armeniaca populations in their native habitats underscores the urgent need for targeted conservation and restoration strategies. This study provides the first comprehensive characterization of P. armeniaca populations in the Almaty region of Kazakhstan, integrating morphological descriptors (46 parameters), molecular markers, geobotanical, and remote sensing analyses. Geobotanical and remote sensing analyses enhanced understanding of accession distribution, geological features, and ecosystem health across sites, while also revealing their vulnerability to various biotic and abiotic threats. Of 111 morphologically classified accessions, 54 were analyzed with 13 simple sequence repeat (SSR) markers and four DNA barcoding regions. Our findings demonstrate the necessity of integrated morphological and molecular analyses to differentiate closely related accessions. Genetic analysis identified 11 distinct populations with high heterozygosity and substantial genetic variability. Eight populations exhibited 100% polymorphism, indicating their potential as sources of adaptive genetic diversity. Cluster analysis grouped populations into three geographic clusters, suggesting limited gene flow across Gorges (features of a mountainous landscape) and greater connectivity within them. These findings underscore the need for site-specific conservation strategies, especially for genetically distinct, isolated populations with unique allelic profiles. This study provides a valuable foundation for prioritizing conservation targets, confirming genetic redundancies, and preserving genetic uniqueness to enhance the efficiency and effectiveness of the future conservation and use of P. armeniaca genetic resources in the region.

Bacterial, fungal, and viral contaminations pose a pervasive challenge to in vitro propagation of berry crops, presenting significant economic hurdles for the preservation of plant genetic resources and the commercialization of micropropagation. This study aimed to diagnose endophytic and viral contamination in commercial blackberry cultivars and while developing an in vitro method to eliminate bacterial contamination from the Chaсanska Bestrna variety. The Plant Preservative Mixture™ (PPM™) was utilized as a broad-spectrum bactericidal agent within the blackberry in vitro tissue culture. Contaminated shoots were cultured on Murashige and Skoog medium supplemented with 0.2% v/v PPM™, maintained over a 12-week period through three subcultures, before being transferred to medium devoid of PPM™ for an additional 12 weeks. The results were evaluated after 12 and 32 weeks of culture on medium without PPM™. This study demonstrated that PPM™ is an effective control agent and can be successfully used to manage the growth of endophytic contamination. For the Chaсanska Bestrna blackberry variety, 100% aseptic shoots were obtained in vitro without any negative effects on the shoot growth. However, the results indicate the opportunity for further testing of PPM™ on other blackberry varieties experiencing bacterial contamination, as it is possible that the contamination in this study was superficial and the selected concentration of the bactericide proved to be successful. To obtain virus-free planting stocks, in vitro rooted shoots were transferred to a soil substrate consisting of peat (40%), black soil (50%), and perlite (10%), and then adapted in a greenhouse at 20-23°С. The survival rate of blackberry varieties in greenhouse conditions was 93-99%. Keywords: blackberry; tissue culture; in vitro contamination; micropropagation; broad-spectrum biocide

Background. The decline of plants in natural populations leads to biodiversity loss and ecosystem disruption. Comprehensive study and restoration of degrading populations, particularly of rare species, is highly relevant. Plant tissue culture biotechnology is an important tool for conserving genetic diversity. Materials and methods. A total of 115 accessions of Prunus armeniaca L. from two populations in Almaty Region were collected and studied employing geobotanical and tissue culture techniques. Results. Descriptor-based evaluation (46 parameters) was conducted, herbarium specimens were prepared, remote sensing was performed, a digital elevation model (DEM) and orthophotomap were created, and NDVI values (0.3–0.7) were calculated. For in vitro initiation of embryonic axes, Knop’s medium proved optimal, with 94.5% viability. Medium 523 showed a low contamination rate (1.1%). The highest multiplication rate (MR) of 2.9 was achieved on the MS5 medium supplemented with 1 mg L ^–1 of 6-benzylaminopurine (BAP) and 0.3 mg L ^–1 of gibberellic acid (GA). Conclusion. The actual condition of the populations was determined: high incidence of damage (up to 52.6%) and absence of fruiting in certain areas. Cartographic maps of the territory were made. The effectiveness of Knop’s medium for in vitro germination of embryonic axes was confirmed, and testing of in vitro shoots on medium 523 showed a low contamination level (1.1%). The highest MR (2.9) was obtained on the MS5 medium with elevated concentrations of BAP and GA.

Background. The relevance is based on the need to preserve the genetic diversity of rare and endangered Rosaceae plants that play an important role in ecosystems and are of value for agriculture, medicine, and ornamental gardening. Materials and methods. Nine plant species from the Rosaceae family listed in the Red Data Book of Kazakhstan served as the material for this study. Results. Accessions of 9 Rosaceae species were collected by plant collecting missions. The in vitro initiation and micropropagation techniques employing the Murashige and Skoog medium with added growth regulators was optimized for 6 species. Conclusion. The established in vitro collection of rare and endangered plants from the Rosaceae family is an effective tool for their conservation and reproduction. The applied techniques ensure long-term conservation of biodiversity and create opportunities for further use of genetic material for scientific and practical purposes.