Class III Peroxidases in the Peach (Prunus persica): Genome-Wide Identification and Functional Analysis.

Class III peroxidases are plant-specific and play a key role in the response to biotic and abiotic stresses, as well as in plant growth and development. In this study, we investigated 60 POD genes from Prunus persica based on genomic and transcriptomic data available in NCBI and analysed the expression of individual genes with qPCR. Peroxidase genes were clustered into five subgroups using the phylogenetic analysis. Their exon-intron structure and conserved motifs were analysed. Analysis of the transcriptomic data showed that the expression of PpPOD genes varied significantly in different tissues, at different developmental stages and under different stress treatments. All genes were divided into low- and high-expressed genes, and the most highly expressed genes were identified for individual tissues (PpPOD12 and PpPOD42 in flower buds and PpPOD73, PpPOD12, PpPOD42, and PpPOD31 in fruits). The relationship between cold tolerance and the level of peroxidase expression was revealed. These studies were carried out for the first time in the peach and confirmed that chilling tolerance may be related to the specificity of antioxidant complex gene expression.

Genetic Diversity of Peach Cultivars from the Collection of the Nikita Botanical Garden Based on SSR Markers.

The Nikita Botanical Garden (NBG) has a unique Prunus L. collection (peach, apricot, plum, cherry) comprising more than 3000 accessions. NBG is also a breeding center for stone fruits, including peach (Prunus persica (L.) Batsch). In the present study a set of 85 peach cultivars bred in NBG, Europe, and North America was analyzed using 12 SSR markers to assess their genetic diversity and relatedness. The detected polymorphism level was comparable to the previous estimates of genetic variability in peach cultivars. The average number of alleles per locus was 5.67, PIC value averaged 0.49, expected, and observed heterozygosity averaged 0.52 and 0.31, respectively. Among the detected alleles, 19 (27.94%) were rare and 12 (17.65%) were unique. All studied accessions except two could be identified with the used marker set. Cluster analysis revealed some groups according to the cultivars' pedigrees. No clear differentiation of the studied sample according to geographic origin or fruit characteristics of peach cultivars was revealed. The results provide valuable information for identification and rational management of the material preserved in the NBG peach collection.