Apple Rootstock Research Articles

Comparative Physiological and Transcriptome Analysis Reveals Potential Pathways and Specific Genes Involved in Waterlogging Tolerance in Apple Rootstocks.

Apple (Malus × domestica Borkh.) is one of the most cultivated fruit crops in China. Apple trees frequently encounter waterlogging stress, mainly due to excess rainfall, soil compaction, or poor soil drainage, results in yellowing leaves and declined fruit quality and yield in some regions. However, the mechanism underlying the response to waterlogging has not been well elucidated. Therefore, we performed a physiological and transcriptomic analysis to examine the differential responses of two apple rootstocks (waterlogging-tolerant M. hupehensis and waterlogging-sensitive M. toringoides) to waterlogging stress. The results showed that M. toringoides displayed more severe leaf chlorosis during the waterlogging treatment than M. hupehensis. Compared with M. hupehensis, the more severe leaf chlorosis induced by waterlogging stress in M. toringoides was highly correlated with increased electrolyte leakage and superoxide radicals, hydrogen peroxide accumulation, and increased stomata closure. Interestingly, M. toringoides also conveyed a higher ethylene production under waterlogging stress. Furthermore, RNA-seq revealed that a total of 13,913 common differentially expressed genes (DEGs) were differentially regulated between M. hupehensis and M. toringoides under waterlogging stress, especially those DEGs involved in the biosynthesis of flavonoids and hormone signaling. This suggests a possible link of flavonoids and hormone signaling to waterlogging tolerance. Taken together, our data provide the targeted genes for further investigation of the functions, as well as for future molecular breeding of waterlogging-tolerant apple rootstocks.

Rootstock–scion interaction affects Malus transcriptome profiles in response to cadmium

Apple production is threatened by cadmium contamination in orchards. Cd accumulation and tolerance in grafted Malus plants is affected by rootstock, scion, and their interaction. This dataset is part of an experiment investigating the molecular mechanism of Cd bioaccumulation and tolerance in different apple rootstock-scion combinations. We exposed four rootstock–scion combinations to Cd treatment consisting of Hanfu and Fuji apple (Malus domestica) scions grafted onto apple rootstocks of M. baccata or M. micromalus “qingzhoulinqin”. RNA sequencing was conducted in roots and leaves of grafting combinations under 0 or 50 μM CdCl2 conditions. A comprehensive transcriptional dataset of affected rootstock, scion, and their interaction among different graft combinations was obtained. This dataset provides new insights in the transcriptional control of Cd bioaccumulation and tolerance in grafting plants regulated by rootstock and scion. Herein, we discuss the molecular mechanism underlying Cd absorption and bioaccumulation.

Pratylenchus vulnus infecting apple rootstock MM106: Defense reaction, plant nutrient alterations and pathogenic potential

Pratylenchus vulnus infecting apple rootstock MM106: Defense reaction, plant nutrient alterations and pathogenic potential

MdWRKY40is directly promotes anthocyanin accumulation and blocks MdMYB15L, the repressor of MdCBF2, which improves cold tolerance in apple

Cold stress is an important factor that limits apple production. In this study, we examined the tissue-cultured plantlets of apple rootstocks ‘M9T337’ and ‘60-160’, which are resistant and sensitive to cold stress, respectively. The enriched pathways of differentially expressed genes (DEGs) and physiological changes in ‘M9T337’ and ‘60-160’ plantlets were clearly different after cold stress (1°C) treatment for 48 h, suggesting that they have differential responses to cold stress. The differential expression of WRKY transcription factors in the two plantlets showed that MdWRKY40is and MdWRKY48 are potential regulators of cold tolerance. When we overexpressed MdWRKY40is and MdWRKY48 in apple calli, the overexpression of MdWRKY48 had no significant effect on the callus, while MdWRKY40is overexpression promoted anthocyanin accumulation, increased callus cold tolerance, and promoted the expression of anthocyanin structural gene MdDFR and cold-signaling core gene MdCBF2. Yeast one-hybrid screening and electrophoretic mobility shift assays showed that MdWRKY40is could only bind to the MdDFR promoter. Yeast two-hybrid screening and bimolecular fluorescence complementation showed that MdWRKY40is interacts with the CBF2 inhibitor MdMYB15L through the leucine zipper (LZ). When the LZ of MdWRMY40is was knocked out, MdWRKY40is overexpression in the callus did not affect MdCBF2 expression or callus cold tolerance, indicating that MdWRKY40is acts in the cold signaling pathway by interacting with MdMYB15L. In summary, MdWRKY40is can directly bind to the MdDFR promoter in order to promote anthocyanin accumulation, and it can also interact with MdMYB15L to interfere with its inhibitory effect on MdCBF2, indirectly promoting MdCBF2 expression, and thereby improving cold tolerance. These results provide a new perspective for the cold-resistance mechanism of apple rootstocks and a molecular basis for the screening of cold-resistant rootstocks.

The Attraction of Apple Rhizosphere Microorganisms and Changing Leaf Characteristics by Strigolactone

Apple leaf characteristics are the most important vegetative growth and development traits. The apple rhizosphere is also indirectly responsible for apple growth and development. It provides roots with elements and compounds that improve roots’ and shoots’ growth and development. The application of exogenous plant growth regulators such as strigolactones (SLs) has become one of the main trends for improving vegetative growth and enhancing the rhizosphere microbiome. This study aimed to investigate the effect of the exogenous SLs on some leaf characteristics, such as leaf area, angle, nitrogen content, chlorophyll content, and apical area diameter, in addition to the composition of the rhizosphere microbiome of apple M9 rootstock. The apple rootstocks were treated with various concentrations of GR24, an analog of SLs; the concentrations were 0, 1, 5, and 10 µM. The study found that the treatments of 5 µM increased the leaf–stem angles and leaf length while decreasing the apical diameter. The treatments of 1 and 5 µM increased leaf nitrogen content; however, this effect was not observed when using the higher concentration of 10 µM. The lower concentration (1 µM) led to a different abundance and diversity of microorganisms compared to the higher concentration (10 µm).

Exogenous 24-epibrassinolide promoted growth and nitrogen absorption and assimilation efficiency of apple seedlings under salt stress.

High salinity significantly hampers global agricultural productivity. Plants typically undergo lower nitrogen utilization efficiency (NUE) under salt stress. As an active byproduct from brassinolide biosynthesis, 24-epibrassinolide (EBR) is involved in regulating the stress-treated plant N absorption and assimilation. However, the exogenous EBR application effects' on N absorption and assimilation in apple exposed to the salt-stressed condition remains unclear. We sprayed exogenous EBR (0.2 mg L-1) on apple dwarf rootstock (M9T337) seedlings (growing hydroponically) under salt (NaCl) stress in a growth chamber. We analyzed the seedling development, photosynthesis and its-mediated C fixation, N ( ) absorption and assimilation in reponse to exogenous EBR application under salt stress. The findings demonstrated that NaCl stress greatly hampered seedlings' root growth and that exogenous EBR application obviously alleviated this growth suppression. Exogenous EBR-treated plants under NaCl stress displayed the more ideal root morphology and root activity, stronger salt stress tolerance and photosynthetic capacity as well as higher C- and N-assimilation enzyme activities, ion flow rate and nitrate transporter gene expression level than did untreated plants. Furthermore, the results of isotope labeling noted that exogenous EBR application also enhanced 13C-photoassimilate transport from leaves to roots and 15 transport from roots to leaves under NaCl stress. Our findings imply that exogenous EBR application, through strengthening photosynthesis, C- and N-assimilation enzyme activities, nitrate absorption and transport as well as synchronized optimizing the distribution of seedlings' C and N, has a fundamental role in improving NUE in apple rootstock seedlings under salt stress.

Potassium alleviated high nitrogen-induced apple growth inhibition by regulating photosynthetic nitrogen allocation and enhancing nitrogen utilization capacity

There is a close relationship between potassium (K) and nitrogen (N). However, the roles of K under high N conditions remain unclear. Using a hydroponics approach, we monitored the morphological, physiological, and molecular changes in M9T337 apple (Malus domestica) rootstocks under different nitrate (10 and 30 mmol·L−1NO3−) and K supply (0.5, 6, 10, and 20 mmol·L−1 K+) conditions. Results revealed that high nitrate inhibited the root growth of M9T337 rootstocks, downregulated the expressions of K transporter genes (MdPT5, MdHKT1, and MdATK1), and reduced the net NO3− and K+ influx at the surface of roots, thereby resulting in an N/K imbalance in rootstocks. Further investigation showed that 10 mmol·L−1 K increased the activity of N metabolic enzymes (NR, GS, NiR, and GOGAT), upregulated the expressions of genes related to nitrate uptake and transport (MdNRT1.1, MdNRT1.2, MdNRT1.5, and MdNRT2.4), promoted 15N transport from the roots to the shoots, optimized leaf N distribution, and improved photosynthetic N utilization efficiency under high nitrate conditions. These results suggest that the negative effects of high nitrate may be related to the N/K imbalance and that reducing N/K in plants by increasing K supply level can effectively alleviate the inhibition of N assimilation by high nitrate stress.

DNA methylation variation is crucial to restore adventitious rooting ability during in vitro shoot culture-induced rejuvenation in apple rootstock.

In vitro shoot culture has been widely used for restoring adventitious rooting ability in rooting recalcitrant woody perennial species for the past few decades, but its molecular mechanism is largely uncovered. DNA methylation is an essential epigenetic mark that participates in many biological processes. Recent reports suggested a role of DNA methylation in vitro culture in plants. In this study, we characterized the single-base resolution DNA methylome and transcriptome of adult and in vitro shoot culture-induced rejuvenation cuttings of apple rootstock M9T337. We found a global decrease in DNA methylation during rejuvenation, which may be correlated with increased expression of DNA demethylase genes and decreased expression of DNA methyltransferase genes. We additionally documented DNA hypomethylation in 'T337'_R in gene protomer associated with higher transcript levels of several adventitious rooting-related genes. The application of a DNA methylation inhibitor (5-azacytidine) enhanced the adventitious rooting ability and the expression level of adventitious rooting-related genes, such as, MdANT, MdMPK3, MdABCB21, MdCDC48, MdKIN8B, pri-MdMIR156a5 and pri-MdMIR156a12. Together, the DNA hypomethylation is critical for the rejuvenation-dependent adventitious rooting ability in apple rootstock. In addition, increased DNA methylation was also found in thousands of genes in 'T337'_R. We additionally documented that DNA hypermethylation is required for inhibition of adventitious rooting-repressed genes, such as MdGAD5a, encoding glutamate decarboxylase, which can catalyze glutamate decarboxylated to form γ-aminobutyric acid (GABA). Our results revealed that in vitro shoot culture-dependent DNA methylation variation plays important roles in adventitious rooting in apple rootstock.

Fire blight rootstock infections causing apple tree death: A case study in high-density apple orchards with Erwinia amylovora strain characterization

A devastating outcome of fire blight in apple trees is the infection of rootstock, which leads to canker development. Fire blight cankers are infected zones of dead bark on perennial branches, trunk, or rootstock that develop after fire blight pathogen Erwinia amylovora invades wood. Cankers can girdle the trunk, branches and rootstock leading to tree death and production losses, especially significant in high-density orchards. An accurate diagnosis of trunk and rootstock blight is a top challenge for apple growers because fire blight cankers can be visually misdiagnosed with cankers caused by less frequent Oomycete and fungal pathogens (e.g., Phytophthora spp., Botryosphaeria dothidea, B. obtusa, Valsa mali). In addition, detecting E. amylovora in apple rootstocks is essential because this pathogen also causes asymptomatic infections. Accurate fire blight diagnosis is necessary to inform the complete removal of infected trees from the orchard and help replanting efforts while preventing further pathogen dissemination. To determine apple tree losses caused by fire blight rootstock infections, PCR was used to detect E. amylovora in symptomatic and asymptomatic rootstocks for two years. Rootstock canker incidence and tree death were rated in selected infection foci on seven commercial apple orchards in New York. Each infection focus consisted of central rootstock-blighted tree and the nearest surrounding edge trees showing no rootstock blight. E. amylovora strains collected from these seven orchards and other orchards in New York were characterized. In the first year, most of the orchards showed E. amylovora detection rates of 10.7 – 45.3% in asymptomatic rootstocks on the edge trees immediately surrounding visibly infected i.e. rootstock-blighted central trees. One year later, 20.8 – 56.3% cankered rootstocks were detected on the edge trees and from zero to 35.4% dead edge trees were recorded. However, the PCR from sampled edge rootstocks one year later showed no pathogen detections. E. amylovora rootstock strains showed slight variability in enzymatic activity, copper sensitivity, virulence, and exopolysaccharide production. These results elucidate the role and importance of rootstock infections for apple tree survival, the presence of latent fire blight infections, and the valuable utility of molecular detection methods to assist apple tree removal after epidemics.

Transcription factors MhDREB2A/MhZAT10 play a role in drought and cold stress response crosstalk in apple.

Drought and cold stresses seriously affect tree growth and fruit yield during apple (Malus domestica) production, with combined stress causing injury such as shoot shriveling. However, the molecular mechanism underlying crosstalk between responses to drought and cold stress remains to be clarified. In this study, we characterized the zinc finger transcription factor ZINC FINGER OF ARABIDOPSIS THALIANA 10 (ZAT10) through comparative analysis of shoot-shriveling tolerance between tolerant and sensitive apple rootstocks. MhZAT10 responded to both drought and cold stresses. Heterologous expression of MhZAT10 in the sensitive rootstock 'G935' from domesticated apple (Malus domestica) promoted shoot-shriveling tolerance, while silencing of MhZAT10 expression in the tolerant rootstock 'SH6' of Malus honanensis reduced stress tolerance. We determined that the apple transcription factor DEHYDRATION RESPONSE ELEMENT-BINDING PROTEIN 2A (DREB2A) is a direct regulator activating the expression of MhZAT10 in response to drought stress. Apple plants overexpressing both MhDREB2A and MhZAT10 genes exhibited enhanced tolerance to drought and cold stress, while plants overexpressing MhDREB2A but with silenced expression of MhZAT10 showed reduced tolerance, suggesting a critical role of MhDREB2A-MhZAT10 in the crosstalk between drought and cold stress responses. We further identified drought-tolerant MhWRKY31 and cold-tolerant MhMYB88 and MhMYB124 as downstream regulatory target genes of MhZAT10. Our findings reveal a MhDREB2A-MhZAT10 module involved in crosstalk between drought and cold stress responses, which may have applications in apple rootstock breeding programs aimed at developing shoot-shriveling tolerance.

Auxin Participates in the Regulation of the Antioxidant System in Malus baccata Borkh. Roots under Sub-Low Temperature by Exogenous Sucrose Application

Malus baccata Borkh., an apple rootstock, is found to be damaged by oxidation at sub-low root-zone temperature. In previous studies, we have found that exogenous sucrose could alleviate oxidative damage and increase the indole acetic acid (IAA) in roots under sub-low temperature (L). However, the role of IAA in sucrose-induced tolerance to L remains unclear. A pot experiment was conducted to evaluate the effects of exogenous sucrose and IAA synthesis/transport inhibitors (2,3,5-triiodobenzoic acid, TIBA; 4-biphenylboronic acid, BBo) on growth, IAA levels, sugars, and the antioxidant system of M. baccata under L. The results showed that the L treatment decreased IAA contents by 23.69% (48 h) and induced significant increases in root contents of malondialdehyde (MDA) and reactive oxygen (ROS), along with increasing catalase (CAT), ascorbate peroxidase (APX), and glucose-6-phosphate dehydrogenase (G6PDH) activities, while superoxide dismutase (SOD) and monodehydroascorbate reductase (MDHAR) activities first increased (24 h) and then decreased (48 h), and glutathione reductase (GR) and peroxidase (POD) activities significantly decreased. The L treatment also decreased ascorbate/oxidized ascorbate (AsA/DHA), glutathione/oxidized glutathione (GSH/GSSG), and coenzyme II/oxidized coenzyme II (NADPH/NADP+) ratios. Furthermore, the L treatment increased the contents of sucrose, fructose, glucose and sorbitol in the roots and suppressed plant growth. Sucrose pretreatment significantly increased IAA contents (12.42%, 24 h and 14.44%, 48 h) and decreased MDA and ROS contents, which improved the activities of antioxidant enzymes other than APX and increased the contents of AsA, GSH, and NADPH, and increased sucrose, fructose, and sorbitol contents and promoted plant growth. However, the sucrose + TIBA or BBo treatments decreased IAA contents and attenuated or almost abolished the positive effects of exogenous sucrose under sub-low temperature. Our findings indicate that IAA is involved in the sucrose-induced regulation of the antioxidant system in M. baccata roots under sub-low temperature and we provided theoretical references for further study on the adaptability of apple roots to low temperature.

Integrated transgene and transcriptome reveal the molecular basis of MdWRKY87 positively regulate adventitious rooting in apple rootstock.

For most fruit and forest species vegetative propagated from elite genotypes, adventitious rooting is essential. The ability to form adventitious roots significantly decreased during the juvenile to adult phase change. Apart from the miR156-SPL pathway, whether there is another regulation mechanism controlling age-dependent adventitious rooting ability remained largely unknown. In the present study, we showed that MdWRKY87 expression level was positively correlation with adventitious rooting ability. In addition, over-expressing of MdWRKY87 in tobacco leads to enhanced adventitious rooting ability, more adventitious root number and accelerated adventitious rooting process. Comparative transcriptome profiling indicated that MdWRKY87 overexpression can activate the expression of adventitious rooting-induced genes, such as WOX11 and AIL. In addition, MdWRKY87 overexpression can inhibit the transcription of adventitious rooting-repressed genes, such as AUX/IAAs and type-B cytokinin RRs. Collectively, here we demonstrated that higher expression level of MdWRKY87 contributes to age-dependent adventitious rooting-competent in juvenile apple rootstock.

Strigolactone regulates adventitious root formation via the MdSMXL7-MdWRKY6-MdBRC1 signaling cascade in apple.

Propagation through stem cuttings is a popular method worldwide for species such as fruit tree rootstocks and forest trees. Adventitious root (AR) formation from stem cuttings is crucial for effective and successful clonal propagation of apple rootstocks. Strigolactones (SLs) are newly identified hormones involved in AR formation. However, the regulatory mechanisms underpinning this process remain elusive. In the present study, weighted gene co-expression network analysis, as well as rooting assays using stable transgenic apple materials, revealed that MdBRC1 served as a key gene in the inhibition of AR formation by SLs. We have demonstrated that MdSMXL7 and MdWRKY6 synergistically regulated MdBRC1 expression, depending on the interactions of MdSMXL7 and MdWRKY6 at the protein level downstream of SLs as well as the direct promoter binding on MdBRC1 by MdWRKY6. Furthermore, biochemical studies and genetic analysis revealed that MdBRC1 inhibited AR formation by triggering the expression of MdGH3.1 in a transcriptional activation pathway. Finally, the present study not only proposes a component, MdWRKY6, that enables MdSMXL7 to regulate MdBRC1 during the process of SL-controlled AR formation in apple, but also provides prospective target genes to enhance AR formation capacity using CRISPR (i.e. clustered regularly interspaced short palindromic repeats) technology, particularly in woody plants.

Characteristics of composition and content of auxins in tissues of Siberian apple tree <i>Malus baccata</i> L. Borkh.

It is known that the highest content of auxins is found primarily in the areas of active mitosis, including young leaves, apical meristems, cambium, embryos and endosperm, as well as developing fruits, which determines, among other things, plant habitus and fruit size. In agriculture and biotechnology, auxins (indole-3-butyric acid (IBA) and indole-3-acetic acid (IAA) are used to stimulate lateral development, including in apple tree rootstocks. Despite the crucial role of endogenous IBA in rooting, its presence in apple tree tissues remains unconfirmed, although its content in planta was shown for many other plants. Therefore, in this work, the composition and content of auxins in 2 tissue types of Siberian apple tree of lowand high-growing forms, along with the presence of IBA in them, was compared. Tissues of ovary and bark of Siberian apple tree (Malus baccata L. Borkh.) of 2 forms (low and tall) growing on an experimental plot of Siberian Institute of Plant Physiology and Biochemistry SB RAS were used in the study. Bark samples were collected from the 1st year shoots at the stage of intensive sap flow. The ovary samples were collected in July at the stage of active growth. Auxins purified by solid-phase extraction were analysed by GC-MS. In addition to IAA-3, the following auxins were found in fast-growing tissues of the Siberian apple tree both in the cambium layer of annual gain during intensive sap flow and set fruit during the active growth stage: IBA, indole-1-acetic acid, indole-3-carboxylic acid and indole-3-propionic acid. Similar to other plants, the content of these auxins was significantly lower than that of endogenous IAA.

Transcriptome Analysis of the Effects of Grafting Interstocks on Apple Rootstocks and Scions.

Apples are a major horticultural crop worldwide. Grafting techniques are widely utilized in apple production to keep the varieties pure. Interstocks are frequently used in Northern China to achieve intensive apple dwarfing cultivation. High-throughput sequencing was used to investigate differentially expressed genes in the phloem tissues of two different xenograft systems, M ('Gala'/'Mac 9'/Malus baccata (L.) Borkh.) and B ('Gala'/Malus baccata (L.) Borkh.). The results showed that dwarfing interstocks could significantly reduce the height and diameters of apple trees while have few effects on the growth of annual branches. The interstocks were found to regulate the expression of genes related to hormone metabolism and tree body control (GH3.9, PIN1, CKI1, ARP1, GA2ox1 and GA20ox1), these effects may attribute the dwarf characters for apple trees with interstocks. Besides, the interstocks reduce photosynthesis-related genes (MADH-ME4 and GAPC), promote carbon (C) metabolism gene expression (AATP1, GDH and PFK3), promote the expression of nitrogen (N)-metabolism-related genes (NRT2.7, NADH and GDH) in rootstocks, and improve the expression of genes related to secondary metabolism in scions (DX5, FPS1, TPS21 and SRG1). We also concluded that the interstocks acquired early blooming traits due to promotion of the expression of flowering genes in the scion (MOF1, FTIP7, AGL12 and AGL24). This study is a valuable resource regarding the molecular mechanisms of dwarf interstocks' influence on various biological processes and transplantation systems in both scions and rootstocks.

Progress in apple breeding for resistance to fire blight

The paper presents the most important issues concerning the breeding of apple trees resistant to fire blight, which creates great op­portunities to increase the efficiency of apple fruit production without the use of other protection methods, including the chemical treatment. The phenotypic assessment of susceptibility of apple genotypes to the disease is based on observations on the occurrence of symptoms in field and/or closed facilities, e.g. in the greenhouse. Molecular biology methods, including identification of resistance mark­ers, and biotechnology are valuable tools to accelerate the breeding process. Breeding programs conducted in various research centers around the world use wild species of the genus Malus and commercial cultivars of apple. Apple rootstocks with very high resistance to fire blight (USA) and a number of scab-resistant cultivars, also showing high resistance to the disease (Germany, Switzerland) have already been bred. In recent years cultivar Early Szampion and clone No. 69 (J-2003-05) have been bred in Poland. Both genotypes are characterized by a very high resistance, and produce attractive tasty fruit. They have the prospect of being used in breeding programs and commercial plantings.

Optimization of critical determinants for efficient transformation in M7 apple root stock

Optimization of critical determinants for efficient transformation in M7 apple root stock

Hydraulic conductivity and native embolism of Geneva® Series apple rootstocks measured by the XYL’EM-Plus® embolism meter

Hydraulic conductivity and native embolism of Geneva® Series apple rootstocks measured by the XYL’EM-Plus® embolism meter

Comprehensive analysis revealed that titanium dioxide nanoparticles could strengthen the resistance of apple rootstock B9 to saline-alkali stress.

Apple growth and development can be adversely affected by saline-alkali stress, which has become a significant factor restricting the high yield of the apple industry. In recent years, nanomaterials have become a potential source for plant growth and development. Titanium dioxide nanoparticles (TiO2 NPs) play an important role in multiple plant development processes, including mitigating environmental stress. In this study, one-year-old apple rootstock B9 stem cuttings were used as research objects. Different concentrations of TiO2 NPs were applied to the roots before saline-alkali treatment. Principal component analysis showed that 1gkg-1 TiO2 NPs treatment had the best effect in alleviating the stress for B9. It significantly reduced the damage to B9 under salt-alkali stress, increased the content of photosynthetic pigment, enhanced the performance of Photosystem II, and promoted photosynthesis. At the same time, the content of K+ was increased, and the ion toxicity was alleviated. In addition, TiO2 NPs have also been shown to reduce B9 cell damage and lipid peroxidation, increase antioxidant enzyme activity, and regulate the accumulation of solutes. Overall, this study provides a theoretical basis for TiO2 NPs to mitigate the adverse effects of plants under saline-alkali stress and provides useful insights for managing other plants affected by global salinity and alkalinity.

The content of polyphenols in low-growing apple rootstocks depending on the type of soil in Central Russia

Field studies were carried out in 2017-2021. in horticultural farms of Central Russia. We analyzed 11 varieties of apple trees in four seasons (winter, spring, summer, autumn) for the content of polyphenols in the rootstocks of apple trees - dwarf 62-396, semi-dwarf 54-118 and dwarf PB-9, grown on 7 types of soil: floodplain granular, floodplain layered , podzolized chernozem, leached chernozem, meadow-chernozem, gray forest and sod-podzolic soil. It was found that of all the organs of cultivated varieties of apple trees, the largest amount of polyphenols is concentrated in 1-2-year-old shoots. The highest concentration of flavonols in the shoots of all studied rootstocks and catechins in the shoots of rootstock 54-118 was when growing on the most low-fertile soddy-podzolic soil. It was found that the content of flavonols in apple shoots is less affected by the weather conditions of the year than the content of catechins. The content of catechins in the annual shoots of the apple tree is an unstable variable indicator. Its value may increase or decrease by 5.4-12.0 times during the first two years. Of the three apple tree rootstocks, the largest amount of flavonols was noted in shoots 62-396, and catechins - in shoots 54-118. It was found that with an increase in the proportion of fine dust and physical sand and a decrease in the proportion of medium dust in the soil, the content of flavonols in the shoots of the dwarf apple rootstock 62-396 increases, the less medium dust in the soil, the more flavonols are contained in the shoots of the semi-dwarf apple rootstock 54-118. With an increase in the content of medium dust in the soil, the content of catechins increases in the shoots of the dwarf rootstock of the PB-9 apple tree. It was proposed that the accumulation of flavonols in the annual shoots of apple rootstocks should be considered as an adaptation to a decrease in soil fertility.