Low plasma levels of the vitamin D metabolite 25-hydroxyvitamin D [25(OH)D] and the vitamin D receptor (VDR) gene single nucleotide polymorphisms (SNPs) have been associated with the body’s susceptibility to infectious diseases, including COVID-19. In this pilot retrospective study, representatives of the Kazakh population (central Kazakhstan) were divided into groups based on the test for IgM and IgG for coronavirus infection. We compared the 25(OH)D plasma levels and concluded that the COVID-19-positive group values (25.17 ng/mL ± 16.65) were statistically lower (p = 0.0114) compared to the COVID-19-negative ones (35.58 ng/mL ± 20.67). There was no association between age, gender and 25(OH)D concentration within the groups (p > 0.05). The genotyping of rs2228570 was performed using a TaqMan Real-Time PCR assay. Allele C predominated among the COVID-19-negative participants and significantly reduced the likelihood of coronavirus infection (p < 0.0001; OR = 0.0804; 95% CI 0.02357–0.2798). There were no statistically significant differences in the frequencies of the A, G and T alleles in the studied groups (p > 0.05). The GG genotype of rs2228570 was associated with a 4.131-fold increased likelihood of COVID-19 infection (p = 0.0288; χ² = 5.364; OR = 4.131; 95% CI 1.223–13.71). Comprehensive studies are required to determine whether low 25(OH)D plasma concentrations and genetic background represent a risk factor for COVID-19 infection.

The sustainable preservation of valuable agronomic taxa is critical to addressing global challenges like climate change, which threaten agricultural productivity and food security. Sudan grass, a vital forage crop in arid regions, requires effective conservation methods to maintain its genetic integrity and availability for future use. Current storage techniques are inadequate, making cryopreservation essential for ensuring seed viability and long-term accessibility. An experiment to study Sudanese grass for seed germination was carried out from 2021 to 2023. The objects of the study include four varieties of Sudanese grass. The low concentrations of cryoprotectants of 5-20% were used in the study as some destructive effect on seeds was manifested at the higher concentrations. Despite this fact, the toxic effect of PVS 2 and some concentrations of DMSO was also observed. The results of the study showed that PVS 2 and cryopreservation, without a cryoprotectant, reduce the germination of seeds of the Sudanese grass in the Alina variety by 12% and 18%, respectively. As for the Nika variety, PVS 2 did not have a detrimental effect on seed germination, demonstrating the best germination among all variants (88%). Referring to the Tugai variety, a high germination rate of about 92-95% was observed in all variants of the experiment, which indicated the positive effect of cryoprotectants on the seeds of this particular variety. It has been observed that when studying morphological parameters, seed immersion without cryoprotectants contributed to an increase in the length of the coleoptile in the seedlings of all varieties. PVS2 has a significant reduction in root length by 7.89 cm in the Novosibirskaya 84 variety and by 5.65 cm in the Alina variety compared with the control. In the Tugai variety and Novosibirskaya 84 variety, the use of cryoprotectants affected a decrease in the leaf length compared with the control. Whereas for the Nika variety, cryoprotectants contributed to an increase in the length of the leaf plate. Thus, PVS 2 is recommended as a cryoprotectant for the Nika variety, as well as DMSO and PVS 2 for the Tugai variety to increase seed germination.