TY - JOUR

T1 - Differential accumulation of phenolics and phytoalexins in seven Malus genotypes cultivated in apple replant disease-affected soil

AU - Siefen, Nils

AU - Staudt, Jannika

AU - Busnena, Belnaser A.

AU - Orth, Nils

AU - Beuerle, Till

AU - Lankes, Christa

AU - Baab, Gerhard

AU - Beerhues, Ludger

AU - Winkelmann, Traud

AU - Schmitz, Michaela

AU - Liu, Benye

N1 - Funding Information: This study was supported by the German Research Foundation (DFG, BE 1174/19-1) and the Federal Ministry of Research and Education (BMBF) via the project BonaRes-ORDIAmur (031B0512A, 031B0512D, and 031B0512H). Belnaser Busnena is grateful to the German Academic Exchange Service (DAAD) for providing him with a scholarship. The authors thank Eike Luedeling (Horticultural Sciences, University of Bonn) for his helpful feedback; Gertrudis Heimes (University of Bonn) and Ewa Schneider and Bärbel Ernst (Leibniz University Hannover) for their technical assistance; Josef Bauer (Dienstleistungsplattform Pflanzenversuche, Bonn) for facilitating the greenhouse experiment; Kristin Hauschild (Julius Kühn Institute, Institute for Epidemiology and Pathogen Diagnostics) for support in conducting the CFUs; Christian Heck (HGoTECH GmbH) for the possibility of taking the root scans; and Andreas Wrede (Agricultural Chamber, Schleswig-Holstein) for providing and excavating the soil in Heidgraben.

PY - 2024/3/15

Y1 - 2024/3/15

N2 - Apple replant disease (ARD) is a globally recognised soil-borne disease, which affects apple orchards and tree nurseries. Biotic factors are considered to be the main causal agent of ARD. Phenolics and phytoalexins were induced in apple roots grown in ARD soil compared to roots grown in disinfested ARD soil. However, the relationship between ARD susceptibility and production of phenolics and phytoalexins in apple roots is still unclear. To answer this question, we cultivated seven Malus genotypes with varying levels of ARD susceptibility (M.26, EMR 2, M.200, G.214, G.935, Selection 4, and MAL0739) in both ARD soil from Heidgraben, Germany, and the same soil after disinfestation by gamma-irradiation (γ-ARD). Despite the overall growth reduction observed for all seven genotypes, three of them, EMR 2, G.935 and MAL0739, showed better performance, as indicated by the ARD susceptibility index (ASI) and differences in their root structure. Phenolics and phytoalexins were differentially induced in the roots grown for four weeks (T4) and eight weeks (T8) in ARD soil compared to γ-ARD soil. Moreover, differences in the total phenolics content (TPC) and the total phytoalexin content among the evaluated Malus genotypes were observed. The biochemical data from the early time point (T4) separated Malus genotypes more effectively compared to that from the late time point (T8). Among the six ARD-induced phytoalexins, 3-hydroxy-5-methoxybiphenyl at T4 can serve as an early biomarker for ARD. Although TPC and total phytoalexin content of the Malus genotypes exhibited no or weak correlation with root and shoot growth reduction, some individual phenolics and phytoalexins showed higher coefficients, suggesting that they might influence the ARD susceptibility of apple rootstocks.

AB - Apple replant disease (ARD) is a globally recognised soil-borne disease, which affects apple orchards and tree nurseries. Biotic factors are considered to be the main causal agent of ARD. Phenolics and phytoalexins were induced in apple roots grown in ARD soil compared to roots grown in disinfested ARD soil. However, the relationship between ARD susceptibility and production of phenolics and phytoalexins in apple roots is still unclear. To answer this question, we cultivated seven Malus genotypes with varying levels of ARD susceptibility (M.26, EMR 2, M.200, G.214, G.935, Selection 4, and MAL0739) in both ARD soil from Heidgraben, Germany, and the same soil after disinfestation by gamma-irradiation (γ-ARD). Despite the overall growth reduction observed for all seven genotypes, three of them, EMR 2, G.935 and MAL0739, showed better performance, as indicated by the ARD susceptibility index (ASI) and differences in their root structure. Phenolics and phytoalexins were differentially induced in the roots grown for four weeks (T4) and eight weeks (T8) in ARD soil compared to γ-ARD soil. Moreover, differences in the total phenolics content (TPC) and the total phytoalexin content among the evaluated Malus genotypes were observed. The biochemical data from the early time point (T4) separated Malus genotypes more effectively compared to that from the late time point (T8). Among the six ARD-induced phytoalexins, 3-hydroxy-5-methoxybiphenyl at T4 can serve as an early biomarker for ARD. Although TPC and total phytoalexin content of the Malus genotypes exhibited no or weak correlation with root and shoot growth reduction, some individual phenolics and phytoalexins showed higher coefficients, suggesting that they might influence the ARD susceptibility of apple rootstocks.

KW - Apple rootstock

KW - Biphenyl

KW - Dibenzofuran

KW - Epicatechin

KW - Phloridzin

KW - Root anatomy

UR - http://www.scopus.com/inward/record.url?scp=85183659081&partnerID=8YFLogxK

U2 - 10.1016/j.scienta.2024.112902

DO - 10.1016/j.scienta.2024.112902

M3 - Article

AN - SCOPUS:85183659081

VL - 328

JO - Scientia horticulturae

JF - Scientia horticulturae

SN - 0304-4238

M1 - 112902

ER -