Author:
Liu Ce,Jia Yanhong,He Lixia,Li Hui,Song Jian,Ji Lizhu,Wang Chunguo
Abstract
Abstract
Background
Grafting is widely used as an important agronomic approach to deal with environmental stresses. However, the molecular mechanism of grafted tomato scions in response to biotic stress and growth regulation has yet to be fully understood.
Results
This study investigated the resistance and growth performance of tomato scions grafted onto various rootstocks. A scion from a gray leaf spot-susceptible tomato cultivar was grafted onto tomato, eggplant, and pepper rootstocks, creating three grafting combinations: one self-grafting of tomato/tomato (TT), and two interspecific graftings, namely tomato/eggplant (TE) and tomato/pepper (TP). The study utilized transcriptome and DNA methylome analyses to explore the regulatory mechanisms behind the resistance and growth traits in the interspecific graftings. Results indicated that interspecific grafting significantly enhanced resistance to gray leaf spot and improved fruit quality, though fruit yield was decreased compared to self-grafting. Transcriptome analysis demonstrated that, compared to self-grafting, interspecific graftings triggered stronger wounding response and endogenous immune pathways, while restricting genes related to cell cycle pathways, especially in the TP grafting. Methylome data revealed that the TP grafting had more hypermethylated regions at CHG (H = A, C, or T) and CHH sites than the TT grafting. Furthermore, the TP grafting exhibited increased methylation levels in cell cycle related genes, such as DNA primase and ligase, while several genes related to defense kinases showed decreased methylation levels. Notably, several kinase transcripts were also confirmed among the rootstock-specific mobile transcripts.
Conclusions
The study concludes that interspecific grafting alters gene methylation patterns, thereby activating defense responses and inhibiting the cell cycle in tomato scions. This mechanism is crucial in enhancing resistance to gray leaf spot and reducing growth in grafted tomato scions. These findings offer new insights into the genetic and epigenetic contributions to agronomic trait improvements through interspecific grafting.
Funder
the Innovative Research and Experimental Project of Young Researchers in the Tianjin Academy of Agricultural Sciences
the Tianjin Science and Technology Plan Project
the Science and Technology Foundation of Tianjin, China
the Natural Science Foundation of China
the Sci-Tech Innovation 2030 Agenda
Publisher
Springer Science and Business Media LLC
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