Quali-Quantitative Study on Phenol Compounds as Early Predictive Markers of Graft Incompatibility: A Case Study on Chestnut (Castanea spp.)

Giovanni Gamba,Gabriele Loris Beccaro,Zoarilala Rinah Razafindrakoto,Dario Donno,Viviana Cisse

doi:10.3390/horticulturae8010032

Giovanni Gamba, Gabriele Loris Beccaro + Show 3 more

Open Access

https://doi.org/10.3390/horticulturae8010032

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Abstract

In recent years, research has focused on phenolic compounds and their putative role as markers of graft incompatibility. Thus far, no studies have been conducted on the role of phenolic compounds in chestnut (Castanea spp.). The present study investigated the content of phenolic compounds in different combinations of Castanea spp. cultivars and rootstocks. Analyses were performed on the inner and outer tissues of chestnut grafts at two phenological sampling stages. The separation, identification and quantification of the phenolic markers via HPLC were preceded by an ultrasonic green extraction. Two chromatographic methods were tested for a total of 15 phenol compounds. Flavonol compounds were not detected, while cinnamic acids were found in low concentrations. The amount of gallic acid turned out to be higher at the graft union of the incompatible combination (20.11 ± 1.47 mg/100 gFW vs. 8.94 ± 1.08 mg/100 gFW). The same pattern was observed for catechin (15.79 ± 1.83 mg/100 gFW vs. 9.63 ± 1.98 mg/100 gFW). Differences in tannin concentrations seemed to be species-specific, and were apparently not related to graft incompatibility. The present work underlines the potential application of certain phenol compounds for the early prediction of graft incompatibility in Castanea spp.

Highlights

In recent years, the comprehension of the grafting process has made great progress; graft incompatibility remains one of the major obstacles in woody plant breeding, and for the nursery industry
Graft incompatibility can induce the undergrowth or overgrowth of the scion, which can provide dysfunctions in water and nutrients’ flow through the graft union, and can cause the wilting of the plant. It occurs at early stages, when vascular connections are forming, but it can appear at the fruiting stage, when the plant has a high demand for water and nutrients [5]
Tissues from the grafting point, 5 cm above and 5 cm below it were collected at two phenological sampling stages: at the callusing time (CAL), 60 days after grafting, and at the end of the vegetative cycle (EVC), 255 days after grafting

Summary

Introduction

The comprehension of the grafting process has made great progress; graft incompatibility remains one of the major obstacles in woody plant breeding, and for the nursery industry. Graft incompatibility can induce the undergrowth or overgrowth of the scion, which can provide dysfunctions in water and nutrients’ flow through the graft union, and can cause the wilting of the plant. It occurs at early stages, when vascular connections are forming, but it can appear at the fruiting stage, when the plant has a high demand for water and nutrients [5]

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