Anatomy and genetics of graft compatibility

Anatomical features from the graft junctions of tomato:tomato, pepper:pepper, tomato:pepper, and pepper:tomato over time were used to inform bioinformatic analysis.

Heterografted tomato and pepper plants show severe vascular patterning defects 30 days after-grafting (DAG). (A-D) Representative images of self-grafted tomato (A), heterografted tomato:pepper (B), pepper:tomato (C), and self-grafted pepper (D) plants taken 30 DAG. White arrows indicate graft junctions. High-resolution confocal imaging of vascular anatomy for self-grafted tomato (E, I), heterografted tomato:pepper (F, J) and pepper:tomato (G, K), and self-grafted pepper (H, L) plants taken at 30 DAG. Tissues were stained with propidium iodide to visualize cell walls, and cleared in methyl salicylate. White arrowheads point to xylem bridges. In A-D scale bars = 2 cm, E-H scale bars = 1 cm, I-L scale bars = 400 um. 
Time-specific modules and their major regulators identified in tomato:tomato and pepper:pepper self-graft gene regulatory networks. (A-B) Causal relations were predicted with a dynamic Bayesian network approach between differentially expressed transcription factors and DEGs associated with Gene Ontology categories related to grafting for the (A) tomato:tomato self-graft and (B) pepper:pepper self-graft. Green, blue and red arrows represent regulations at 1 DAG, 3 DAG, and 5 DAG, respectively. Yellow and grey nodes represent transcription factors and non-transcription factors, respectively. (C-D) Highlighted inferred interactions in the main text from the tomato:tomato (C) and pepper:pepper (D) networks. (E) Sankey diagram visualizing inferred gene regulatory interactions from the tomato:tomato and pepper:pepper networks. The width of the connections between each vertical block represents the number of genes (from left to right): contained within each graft combination network, within each TF family, downstream of the major hub, expressed at a specific time point, and that fall into a specific GO-cluster. All TFs that have an outdegree > 0 are included. (F) Percentage of the downstream target genes associated with each GO-cluster per time point. * = p-value < 0.05 (Fisher exact test).


  • Grafting, plant care
  • Histology and confocal microscopy (propidium iodide, auramine O, calcufluor white)
  • Bioinformatics (RNA seq analysis)
  • Statistics

See associated publication: Gene regulatory networks for compatible versus incompatible grafts identify a role for SlWOX4 during junction formation

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