Changes in Cell/Tissue Organization and Peroxidase Activity as Markers for Early Detection of Graft Incompatibility in Peach/Plum Combinations

Abstract

<jats:p>Changes in cell and tissue organization and in peroxidase activity have been analyzed to find early markers to predict graft incompatibility occurrence in peach/plum combinations (<jats:italic>Prunus persica</jats:italic>/<jats:italic>Prunus</jats:italic> spp.) at 5 months after grafting in the dormancy period. Different compatible and incompatible peach/plum grafts were grown for 5 months in a nursery. The cellular study of the graft interface revealed structural changes associated with graft incompatibility symptoms. The main structural features were cambium cell disorganization, less differentiation of vascular tissues, degeneration of phloem and xylem cells, and accumulation of phenols at the graft interface after 5 months of graft development. The peroxidase study was performed during dormancy and the vegetative growth period, and revealed a significant increase in peroxidase activity in the incompatible unions, with significant differences between compatible and incompatible grafts. Analysis of gel profiles of nonbudded rootstocks and scions revealed an anodal isoperoxidase band [relative front (Rf) = 0.48] present in scions and compatible rootstocks, and another isoperoxidase band (Rf = 0.53) only present in the incompatible rootstocks. Our results show that the analysis of cell organization to detect early structural events and the evaluation of peroxidase activity at graft unions constituted feasible and convenient methods for early diagnosis of graft incompatibility. Also, it was suggested that the presence of band Rf = 0.48 in plum rootstocks and peach cultivars could be used as a marker to predict graft compatibility for peach scions and plum rootstocks.</jats:p>

An overview of grafting re-establishment in woody fruit species

“…Thus, the present review provides an overview of the current state of the art for grafting woody plants based on several review articles, research articles, and book chapters, each emphasizing a speci c aspect fi of the procedure, such as grafting techniques or the vascular alignment of cambium tissues ( ; ), candidate gene Pina et al, 2012Lima et al, 2017 ), phenolic compounds ( Chen et al, 2017Zarrouk et al, 2010Irisarri et al, 2016Prabpreea et al, 2018 ; ; ), or phytohormones ( ; ). In addition, several reports fol- Wang et al, 2014Xu et al, 2015 lowing the restoration of the vascular connection focus on scion root-stock interaction in relation to leaf gas exchange ( ; Xu et al, 2015Baron et al, 2017Moreno et al, 2014, ion accumulation ( ; ė 2016), production, and vigor, among other factors.…”

“…The localized type of incompatibility is characterized by anatomical irregularities at the graft union interface accompanied by anatomical abnormalities of the vascular tissue, as well as breaks in cambial and vascular continuity and poor vascular connections ( ;Errea et al, 2001Zarrouk et al, 2010Hartmann et al, 2011 ). These structural anomalies cause mechanical weakness of the union, which may break over time or following strong wind conditions, which would subsequently lead to major economic losses.…”

“…). Zarrouk et al, 2010 In plants of the genus , the accumulation of phenolic com-Prunus pounds is related to problems in the di erentiation of the callus in the ff initial growth stages of grafted plants. Additionally, the veri cation of fi other phenolic compounds, such as catechins and protocyanidins, may aid our understanding of graft-compatible/incompatible relationships (…”

Peroxidase activity and initial growth of ‘Barbosa’ peach on clonal rootstocks

“…Graft incompatibility symptoms in woody species include bark thickening in the connection region, chlorotic leaves, premature leaf fall, budding delay, vigor differences between rootstock and scion, excessive stem thickening below, above or at the point of graft union, graft union disruption, reduced vegetative growth, low productivity and premature plant death (USENIK et al, 2006;HARTMANN et al, 2011;ZARROUK et al, 2010).…”

The Impacts of Tumorigenic and NontumorigenicAgrobacterium vitisStrains on Graft Strength and Growth of Grapevines

“…Because crown gall in nurseries and in young vineyards is frequently first observed at graft unions, we hypothesize that A. vitis, which is distributed randomly in and on grapevines, affects graft strength, resulting in reduced graft take. Several methods have been used to measure the physical properties of graft unions such as hydraulic conductance measurement, microscopy, and tensile strength testing (Atkinson et al 2003;Moore 1983;Zarrouk et al 2010). Tensile strength in tomato plants has been reported primarily as force divided by grafted area, with force being applied by hand and measured with a pull-force gauge (Bausher 2013;Lindsay et al 1974;Moore 1983;Parkinson and Yeoman 1982).…”