Comparisons of Anatomical Characteristics and Transcriptomic Differences between Heterografts and Homografts in Pyrus L.

Abstract

Pear (Pyrus L.) is an important temperate fruit worldwide, and grafting is widely used in pear vegetative propagation. However, the mechanisms of graft healing or incompatibility remain poorly understood in Pyrus. To study the differences in graft healing in Pyrus, the homograft “Qingzhen D1/Qingzhen D1” and the heterograft “QAUP-1/Qingzhen D1” as compatibility and incompatibility combinations were compared. Anatomical differences indicated the healing process was faster in homografts than in heterografts. During the healing process, four critical stages in graft union formation were identified in the two types of grafts. The expression of the genes associated with hormone signaling (auxin and cytokinins), and lignin biosynthesis was delayed in the healing process of heterografts. In addition, the PbBglu13 gene, encoded β-glucosidase, was more highly up-regulated in heterografts than in homografts to promote healing. Meanwhile, the most of DEGs related starch and sucrose metabolism were found to be up-regulated in heterografts; those results indicated that cellulose and sugar signals were also involved in graft healing. The results of this study improved the understanding of the differences in the mechanisms of graft healing between homografts and heterografts.

Genome-wide identification and expression analysis of xyloglucan endotransglucosylase/hydrolase genes family in Salicaceae during grafting

“…These are key points to improve the survival rate of grafting [50] . The high survival rate of reciprocal grafted plants is also related to the positive expression of cell wall related genes [51,52] . Our results found that the expression levels of PtrXTH22 and PtrXTH17 in the low survival rate grafted combination S/P were higher than those in the high survival rate grafted combination, which may play an important regulatory role in the healing process of S/P grafting.…”

Transcriptomic analysis provides an insight into the function of CmGH9B3, a key gene of β‐1, 4‐glucanase, during the graft union healing of oriental melon scion grafted onto squash rootstock

“…Grafting is an ancient horticultural technology widely used to improve yield, quality, and stress tolerance. [ 3 ] It has been widely used in the cultivation and variety improvement of horticultural crops and has created substantial economic value. [ 4 ] Graft union healing is the key to the survival of grafted seedlings, and it is a critical problem to realize the improved properties of grafts.…”