Adverse environmental conditions, including drought stress, pose a significant threat to plant survival and agricultural productivity, necessitating innovative and efficient approaches to enhance their resilience. MicroRNAs (miRNAs) are recognized as key elements in regulating plant adaptation to drought stress, with a notable ability to modulate various physiological and molecular mechanisms. This review provides an in-depth analysis of the role of miRNAs in drought response mechanisms, including abscisic acid (ABA) signaling, reactive oxygen species (ROS) detoxification, and the optimization of root system architecture. Additionally, it examines the effectiveness of bioinformatics tools, such as those employed in in silico analyses, for studying miRNA-mRNA interactions, as well as the potential for their integration with experimental methods. Advanced methods such as microarray analysis, high-throughput sequencing (HTS), and RACE-PCR are discussed for their contributions to miRNA target identification and validation. Moreover, new data and perspectives are presented on the role of miRNAs in plant responses to abiotic stresses, particularly drought adaptation. This review aims to deepen the understanding of genetic regulatory mechanisms in plants and to establish a robust scientific foundation for the development of drought-tolerant crop varieties.

Apple (Malus domestica Borkh.) production is increasingly threatened by fungal diseases under conditions of intensive horticulture and ongoing climate change. In southeastern Kazakhstan, symptoms associated with Alternaria spp. have become more frequent in commercial orchards; however, molecularly confirmed data on the pathogen associated with these symptoms remain limited. This study aimed to identify, using multigene molecular phylogenetic analysis, an Alternaria isolate obtained from infected apple leaves and fruits, to confirm its pathogenicity experimentally, and to compare the susceptibility of apple cultivars to this pathogen. For molecular identification, nucleotide sequences of four genetic markers—the ITS region of rDNA, SSU, tef1-α, and RPB2—were obtained by PCR and sequencing. The sequences were compared with reference data from the GenBank database using BLASTn, and phylogenetic relationships were inferred using the maximum likelihood method based on a concatenated dataset of the four loci. The isolate KZ17 clustered within the A. alternata clade, with the broader node uniting this group with A. gossypina and A. longipes receiving a bootstrap value of 78%. A total of 20 fungal isolates were obtained from 112 symptomatic apple leaf and fruit samples. Among them, one representative isolate, KZ17, was selected for multilocus molecular identification and pathogenicity testing. The pathogenicity of isolate KZ17 was confirmed in inoculation experiments on apple microshoots under controlled conditions. Artificial inoculation of detached leaves and ripe fruits of 14 apple cultivars revealed significant cultivar-dependent differences in susceptibility. Lesion diameters ranged from 12.3 ± 0.20 to 19.2 ± 0.35 mm on detached leaves and from 15.0 ± 1.2 to 30.0 ± 2.4 mm on ripe fruits. The least susceptible cultivars were ‘Granny Smith’, ‘Zaman’, and ‘Maksat’, whereas ‘Voskhod’, ‘Saltanat’, and ‘Kamila’ showed the greatest susceptibility. These differences were statistically significant (p < 0.001). This study provides the first multigene-based confirmation of the association of A. alternata with apple leaf and fruit lesions in southeastern Kazakhstan and demonstrates cultivar-dependent differences in susceptibility to this pathogen. These findings contribute to improved pathogen diagnostics, germplasm screening for resistance, and the development of plant protection strategies for commercial apple orchards.

Cuscuta campestris Yunck. is one of the most destructive parasitic weeds worldwide, causing substantial economic losses because of its broad host range, prolific seed production, and long-term persistence in the soil seed bank. The limited effectiveness and environmental constraints of conventional control measures have intensified the search for sustainable biological alternatives. This study investigated indigenous fungi associated with C. campestris in Kazakhstan as prospective biological control candidates. During field surveys conducted in southern and southeastern Kazakhstan in 2024–2025, symptomatic dodder plants were collected, and 109 fungal isolates were recovered from stems and seeds, including representatives of Fusarium, Alternaria, and Ascochyta, together with several saprophytic genera. Preliminary in vitro seed assays identified Fusarium proliferatum F6 and Alternaria alternata A5 and A19 as producing the highest percentages of affected seeds, reaching 100% by day 15. No visible disease symptoms were observed in soybean or alfalfa during a seven-day preliminary non-target assay. These findings support further greenhouse, field, and host-range evaluation of the selected isolates and provide a basis for continued development of fungal agents against C. campestris.

Bacterial soft rot of potato is predominantly associated with members of the genera Pectobacterium and Dickeya, whereas the contribution of other bacterial taxa to the etiology of the disease remains insufficiently characterized. This study aimed to characterize a bacterial isolate recovered from potato tubers exhibiting naturally occurring soft rot symptoms in Kazakhstan and to evaluate its pathogenic potential. Twelve bacterial isolates were obtained from symptomatic tissue, of which only isolate ZA4 reproducibly caused pronounced tissue softening and maceration following wound inoculation of healthy tubers, whereas disease development remained minimal in the negative control. Reproduction of characteristic symptoms and subsequent reisolation of the bacterium from experimentally affected tissue fulfilled the principal criteria of Koch’s postulates. Multilocus phylogenetic analysis based on 16S rRNA, gyrB, rpoB, and pyrE sequences assigned isolate ZA4 to Bacillus altitudinis. When tested across five potato cultivars and one commercial sample of unknown cultivar identity, the proportion of macerated tissue ranged from approximately 60–85% at 24 h and varied among the tested materials, increasing to 95–98% at 48 h, indicating rapid progression of tissue maceration under the bioassay conditions. ZA4 also exhibited pectinolytic, cellulolytic, proteolytic, and amylolytic activities. These findings demonstrate that B. altitudinis ZA4 is capable of inducing pronounced tissue maceration and soft-rot symptoms in wounded potato tubers under artificial wound inoculation conditions. However, broader studies encompassing a larger number of samples and a wider geographic area are required to determine the occurrence and epidemiological significance of B. altitudinis in association with potato soft rot in Kazakhstan.