What drives interspecies graft union success? Exploring the role of phylogenetic relatedness and stem anatomy

Abstract

The underlying mechanisms that determine whether two species can form a successful graft union (graft compatibility) remain obscure. Two prominent hypotheses are (1) the more closely related species are, the higher the graft success and (2) the vascular anatomy at the graft junction influences graft success. In this paper these two hypotheses are examined in a systematic way using graft combinations selected from a range of (a) phylogenetically close and more distant legume species, (b) species displaying different germination patterns and (c) scions and rootstocks possessing contrasting stem tissues and vascular patterns. Relatedness of species was not a good predictor of graft compatibility, as vascular reconnection can occur between distantly related species and can fail to occur in some more closely related species. Similarly, neither the stem tissues present at the graft junction nor the vascular anatomy correlated with the success of vascular reconnection. Relatedness and stem anatomy therefore do not appear to be the determining factors in successful vascular reconnection after grafting in legumes. These results are discussed in conjunction with other hypotheses such as the role of auxin.

Tomato Graft Union Failure Is Associated with Alterations in Tissue Development and the Onset of Cell Wall Defense Responses

“…Moreover, new and potentially beneficial graft combinations are not explored due to compatibility barriers. Some incompatibility causes are: (a) genetic distance [7,15,16], (b) physiological and/or anatomical difficulties [14,17], (c) toxic compounds transference [18,19], (d) inadequate cell-to-cell recognition [20], and (e) triggering of stress responses [20][21][22][23].…”

Morphological and Molecular Characterization of Selected Chilean Runner Bean (Phaseolus coccineus L.) Genotypes Shows Moderate Agronomic and Genetic Variability

“…Germination type is often indicative of evolutionary changes among clades [ 23 ], and one of the most relevant morphological traits that differentiates species [ 24 ]. According to Delgado-Salinas [ 6 ], P. coccineus subsp.…”

Vegetable Grafting From a Molecular Point of View: The Involvement of Epigenetics in Rootstock-Scion Interactions

“…An intriguing example is the Solanaceae family where successful grafts have been commercially developed between either tomato or eggplant with potato producing effectively edible fruits from both the rootstock and the scion (TomTato ® and Egg and Chips ® of Thompson and Morgan). However, it was recently proven that plants from different families even distant ones can be grafted successfully (Notaguchi et al, 2020); phylogenetic proximity or similarity in the vascular anatomy of the grafting partners does not seem to result always in grafting realization (Wulf et al, 2020). It is shown that grafting is facilitated by the action of genes such as cellulases that help the reconstruction of cell walls; these genes can facilitate tissue adhesion and promote plant grafting (Kurotani et al, 2020;Notaguchi et al, 2020).…”