The red flesh coloration of apples is a result of a biochemical pathway involved in the biosynthesis of anthocyanins and anthocyanidins. Based on apple genome analysis, a high number of regulatory genes, mainly transcription factors such as MYB, which are components of regulatory complex MYB-bHLH-WD40, and several structural genes (PAL, 4CL, CHS, CHI, F3H, DFR, ANS, UFGT) involved in anthocyanin biosynthesis, have been identified. In this study, we investigated novel genes related to the red-flesh apple phenotype. These genes could be deemed molecular markers for the early selection of new apple cultivars. Based on a comparative transcriptome analysis of apples with different fruit-flesh coloration, we successfully identified and characterized ten potential genes from the plant hormone transduction pathway of auxin (GH3); cytokinins (B-ARR); gibberellins (DELLA); abscisic acid (SnRK2 and ABF); brassinosteroids (BRI1, BZR1 and TCH4); jasmonic acid (MYC2); and salicylic acid (NPR1). An analysis of expression profiles was performed in immature and ripe fruits of red-fleshed cultivars. We have uncovered genes mediating the regulation of abscisic acid, salicylic acid, cytokinin, and jasmonic acid signaling and described their role in anthocyanin biosynthesis, accumulation, and degradation. The presented results underline the relationship between genes from the hormone signal transduction pathway and UFGT genes, which are directly responsible for anthocyanin color transformation as well as anthocyanin accumulation during apple-fruit ripening.

Blackcurrant (Ribes nigrum L., family Grossulariaceae) is a perennial shrub that is widely cultivated for its edible berries. These are rich in antioxidants, vitamin C and anthocyanins, making them a valuable ingredient in the food and beverage industry. However, prolonged periods of drought during the fruiting season lead to drought stress, which has serious ecological and agricultural implications, inhibiting blackcurrant growth and reducing yields. To facilitate the analysis of underlying molecular processes, we present the first high-quality chromosome-scale and partially haplotype-resolved assembly of the blackcurrant genome (cv. Rosenthals Langtraubige), also the first in the family Grossulariaceae. We used this genomic reference to analyze the transcriptomic response of blackcurrant leaves and roots to drought stress, revealing differentially expressed genes with diverse functions, including those encoding the transcription factors bZIP, bHLH, MYB and WRKY, and tyrosine kinase-like kinases such as PERK and DUF26. Gene expression was correlated with the abundance of primary metabolites, revealing 14 with significant differences between stressed leaves and controls indicating a metabolic response to drought stress. Amino acids such as proline were more abundant under stress conditions, whereas organic acids were depleted. The genomic and transcriptomic data from this study can be used to develop more robust blackcurrant cultivars that thrive under drought stress conditions.

This review summarises the research projects that have been conducted with the goal of mapping the apple (Malus × domestica) genome. The generation of apple linkage and physical maps, which was started at the end of the 20th century by many scientific teams, has resulted in rich data useful for further fundamental and applied studies. The mapping efforts mainly contained the choice of mapping populations as well as the choice of types and number of markers. Over the years, scientists have achieved major successes and faced major obstacles. Many economically important traits have been mapped in the apple genome, which has a total length of 2000 cM. The recently published integrated genetic and physical maps summarise the data and will be helpful to modern breeding programs, with a special focus on resistance to various diseases, as well as on fruit quality and other desired apple traits.

Open Access Agricultural Journals published by Institute of Agricultural Economics and Information

In the period 2016–2018 the susceptibility to fire blight of seven apple genotypes, including four recently bred was assessed. The studies showed that two of the genotypes (J-2003-05 and ‘Early Szampion’) are highly resistant to the disease. The indicator of assessment was evaluated by the size of necrotized part of terminal shoots after their inoculation with strain Ea659 of Erwinia amylovora. The analysis of disease incidence on individual shoots of both genotypes showed no symptoms on 92% and 100% of shoots inoculated in 2016, 83.8 and 77.0% of shoots in 2017, and 87.8 and 77.3% of shoots inoculated in 2018, respectively. Molecular tests based on 16 genetic markers revealed that genotype J-2003-05 possesses 10 resistance alleles (covering the region of interest from LG 3, 5, 7, 10 and 12). This genotype is derived from the cross between ‘Melfree’ and ‘Sawa’ and produces very large dark-red tasty fruits. Genotype ‘Early Szampion’ representing the selected hybrid from the cross of ‘Gold Milenium’ and ‘Šampion’, producing large, bright red, attractive fruits, was found to possess 10 resistance alleles (covering the region of interest from LG 3, 7, 10 and 12), Both genotypes have the prospect of being used in breeding programs and commercial planting.