Ethylene and expansin biosynthesis related genes polymorphism in local apple (Malus domestica Borkh.) cultivars from VIR Collection of plant genetic resources

Abstract

At Pushkin and Pavlovsk Laboratories of the N.I. Vavilov All-Russian Institute of Plant Genetic Resources (VIR) a diverse collec tion of local apple cultivars is maintained. Some of the cultivars are widely used in breeding programs for their ecological plasticity, increased adaptation to abiotic stress and disease resistance, still there have been no large-scale studies of these local cultivars for fruit storage ability. Fruit softening during storage is an important problem for apple production. Retention of desirable firmness after prolonged storage is one of the key requirements for new apple cultivars. Expansin and ethy lene biosynthesis related genes are known to be involved in control of fruit softening in apple, and gene specific molecular markers have been reported. In this study the polymorphism and allelic configuration of ethylene and expansin biosynthesis related genes Md-ACS1, Md-ACO1 and Md-Exp7 involved in control of fruit softening in 87 local apple cultivars from VIR Collection of Plant Genetic Resources were analyzed. PCR markers Md-ACS1, Md-ACO1 and SSR-marker Md-Exp7 were used in the study. The allele frequencies in the collection generally coincided with the data from previous studies. Md-ACS1 allele 2 associated with reduced ethylene production was found only in three local cultivars, while all the studied local cultivars were heterozygous for the Md-ACO1 locus, as well as most modern Russian apple cultivars. Half of the studied local cultivars were heterozygous for Md-Exp7 (198 : 202). Thirteen local cultivars with rare Md-Exp7 alleles (206, 210 and 212) were detected. No association was found between the Md-Exp7 genotype and the cultivars’ maturation time. The obtained results can be used for additional evaluation of the cultivars’ potential for breeding.

Evaluation of Md-ACS1 gene polymorphism in apple trees for isolation of the identified composition of gene pool and breeding for long-storage fruits

“…Однако, различные аллельные варианты по гену Md-ACS1 не могут показать все разнообразные проявления фенотипа по таким признакам, как длительность периода хранения плодов и сроки их размягчения [11]. Эти сложные процессы обусловлены действием нескольких генов и некоторые из них еще не установлены [13][14][15]. Тем не менее результаты сортового генотипирования перспективны для формирования идентифицированного коллекционного фонда и ускорения селекционного процесса.…”

Identification of apple genes <i>Md-Exp7</i> and <i>Md-PG1</i> alleles in advanced selections resistant to scab

“…When comparing data on allelic variants of the Md-PG1, Md-ACS1 and Md-ACO1 genes and the level of fruit flesh density in 108 apple varieties at the stage of harvesting maturity and after 20 days of storage (at a temperature of 20-25 °С) after harvesting, a relationship was established between the allelic variants of the Md-PG1 and Md-ACS1 genes and the degree of reduction in fruit flesh density (Kwon et al, 2020). Using the DNA markers of the Md-PG1 and Md-Exp7 genes, a number of studies were carried out to identify their alleles, including cultivars and species specimens of the genus Malus (Costa et al, 2008;Longhi et al, 2013a, b;Nybom et al, 2013;Savel'ev et al, 2014a;Shamshin et al, 2018;Savelyeva, Lyzhin, 2019;Dolzhikova et al, 2020), for the purposes of breeding and as part of the study of the allelic diversity of these genes within the genus Malus. For the Md-PG1 and Md-ACS1 genes, allelespecific SNP markers were also deve loped and further integrated into the SNParray for MASselection -International RosBREED SNP Consortium OpenArray v1.0, which allows for the total detection of alleles of 11 genes (Chagné et al, 2019).…”

Evaluation of apple varieties of the Sverdlovsk horticultural breeding station according to the ethylene biosynthesis genes using molecular markers

“…Для изучения генетического потенциала яблони по степени сохранности плодов создан ряд молекулярных маркеров. Они успешно применяются как в зарубежных, так и отечественных исследованиях [3,4,5,6,7,8,9,10,11].…”

“…Аллель Md-ACS1-2 в гомозиготном состоянии не встречается. В большинстве сортов данный ген представлен в гетерозиготном состоянии [2,7,8]. Аналогичная картина наблюдалась и при исследовании местных корейских сортов [20].…”