The graft framework: Quantitative changes in cell wall matrix polysaccharides throughout the tomato graft union formation

AbstractThe use of heterografts is widely applied for the production of several important commercial crops, but the molecular mechanism of graft union formation remains poorly understood. Here, cucumber grafted onto pumpkin was used to study graft union development, and genome-wide tempo-spatial gene expression at the graft interface was comprehensively investigated. Histological analysis suggested that resumption of the rootstock growth occurred after both phloem and xylem reconnection, and the scion showed evident callus production compared with the rootstock 3 days after grafting. Consistently, transcriptome data revealed specific responses between the scion and rootstock in the expression of genes related to cambium development, the cell cycle, and sugar metabolism during both vascular reconnection and healing, indicating distinct mechanisms. Additionally, lower levels of sugars and significantly changed sugar enzyme activities at the graft junction were observed during vascular reconnection. Next, we found that the healing process of grafted etiolated seedlings was significantly delayed, and graft success, xylem reconnection, and the growth of grafted plants were enhanced by exogenous glucose. This demonstrates that graft union formation requires the correct sugar content. Furthermore, we also found that graft union formation was delayed with a lower energy charge by the target of rapamycin (TOR) inhibitor AZD-8055, and xylem reconnection and the growth of grafted plants were enhanced under AZD-8055 with exogenous glucose treatment. Taken together, our results reveal that sugars play a positive role in graft union formation by promoting the growth of cucumber/pumpkin and provide useful information for understanding graft union healing and the application of heterografting in the future.

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Metabolite profiling during graft union formation reveals the reprogramming of primary metabolism and the induction of stilbene synthesis at the graft interface in grapevine

BMC Plant Biology ◽

10.1186/s12870-019-2055-9 ◽

2019 ◽

Vol 19 (1) ◽

Cited By ~ 6

Author(s):

Duyên Prodhomme ◽

Josep Valls Fonayet ◽

Cyril Hévin ◽

Céline Franc ◽

Ghislaine Hilbert ◽

...

Keyword(s):

Amino Acids ◽

Secondary Metabolism ◽

Fruits And Vegetables ◽

Cell Formation ◽

Union Formation ◽

Primary Metabolism ◽

Graft Union ◽

Primary And Secondary Metabolites ◽

Primary And Secondary Metabolism ◽

Graft Interface

Abstract Background Grafting with rootstocks is essential for the culture of many perennial fruit crops and is increasing being used in the production of annual fruits and vegetables. Our previous work based on microarrays showed that transcripts encoding enzymes of both primary and secondary metabolism were differentially expressed during graft union formation in both homo-grafts (a genotype grafted with itself) and hetero-grafts (two different genotypes grafted together). The aim of this study was to profile primary and secondary metabolites, and quantify the activity of phenylalanine ammonia lyase (PAL) and neutral invertase (NI) in the scion and rootstock tissues and the graft interface of homo and hetero-grafts of grapevine 1 month after grafting. Table-top grafting was done on over-wintering stems (canes) of grapevine and the graft interface tissues (containing some woody stem tissues and callus) were compared to the surrounding rootstock and scion tissues. The objective was to identify compounds involved in graft union formation and hetero-grafting responses. Results A total of 54 compounds from primary and secondary metabolism (19 amino acids, five primary and 30 secondary compounds metabolites) and the activity of two enzymes were measured. The graft interface was associated with an increase in the accumulation of the branched-chain amino acids, basic amino acids, certain stilbene compounds and higher PAL and NI activity in comparison to the surrounding woody stem tissues. Some amino acids and stilbenes were identified as being accumulated differently between the graft interfaces of the scion/rootstock combinations in a manner which was unrelated to their concentrations in the surrounding woody stem tissues. Conclusions This study revealed the modification of primary metabolism to support callus cell formation and the stimulation of stilbene synthesis at the graft interface, and how these processes are modified by hetero-grafting. Knowledge of the metabolites and/or enzymes required for successful graft union formation offer us the potential to identify markers that could be used by nurseries and researchers for selection and breeding purposes.

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Characterization of the cell wall matrix polysaccharides and glycoside-hydrolyzing enzymes of Distylium racemosum callus

Plant Science ◽

10.1016/j.plantsci.2009.12.004 ◽

2010 ◽

Vol 178 (2) ◽

pp. 213-220 ◽

Cited By ~ 1

Author(s):

Haruyoshi Konno ◽

Hisaaki Tsumuki ◽

Susumu Nakashima

Keyword(s):

Cell Wall ◽

Cell Wall Matrix ◽

Hydrolyzing Enzymes

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Molecular and physiological characterization of the effects of auxin-enriched rootstock on grafting

Horticulture Research ◽

10.1038/s41438-021-00509-y ◽

2021 ◽

Vol 8 (1) ◽

Author(s):

Longmei Zhai ◽

Xiaomin Wang ◽

Dan Tang ◽

Qi Qi ◽

Huseyin Yer ◽

...

Keyword(s):

Callus Formation ◽

Ethylene Biosynthesis ◽

Union Formation ◽

Biosynthetic Gene ◽

Graft Union ◽

Specific Expression ◽

Physiological Characterization ◽

Graft Healing ◽

Expression Of Genes ◽

Or Gene

AbstractsGrafting is a highly useful technique, and its success largely depends on graft union formation. In this study, we found that root-specific expression of the auxin biosynthetic gene iaaM in tobacco, when used as rootstock, resulted in more rapid callus formation and faster graft healing. However, overexpression of the auxin-inactivating iaaL gene in rootstocks delayed graft healing. We observed increased endogenous auxin levels and auxin-responsive DR5::GUS expression in scions of WT/iaaM grafts compared with those found in WT/WT grafts, which suggested that auxin is transported upward from rootstock to scion tissues. A transcriptome analysis showed that auxin enhanced graft union formation through increases in the expression of genes involved in graft healing in both rootstock and scion tissues. We also observed that the ethylene biosynthetic gene ACS1 and the ethylene-responsive gene ERF5 were upregulated in both scions and rootstocks of the WT/iaaM grafts. Furthermore, exogenous applications of the ethylene precursor ACC to the junction of WT/WT grafts promoted graft union formation, whereas application of the ethylene biosynthesis inhibitor AVG delayed graft healing in WT/WT grafts, and the observed delay was less pronounced in the WT/iaaM grafts. These results demonstrated that elevated auxin levels in the iaaM rootstock in combination with the increased auxin levels in scions caused by upward transport/diffusion enhanced graft union formation and that ethylene was partially responsible for the effects of auxin on grafting. Our findings showed that grafting success can be enhanced by increasing the auxin levels in rootstocks using transgenic or gene-editing techniques.

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Comparative in situ analyses of cell wall matrix polysaccharide dynamics in developing rice and wheat grain

Planta ◽

10.1007/s00425-014-2201-4 ◽

2014 ◽

Vol 241 (3) ◽

pp. 669-685 ◽

Cited By ~ 27

Author(s):

Richard Palmer ◽

Valérie Cornuault ◽

Susan E. Marcus ◽

J. Paul Knox ◽

Peter R. Shewry ◽

...

Keyword(s):

Cell Wall ◽

Wheat Grain ◽

Cell Wall Matrix

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Nucleotide sugars and glycosyltransferases for synthesis of cell wall matrix polysaccharides

Plant Physiology and Biochemistry ◽

10.1016/s0981-9428(00)00167-4 ◽

2000 ◽

Vol 38 (1-2) ◽

pp. 69-80 ◽

Cited By ~ 74

Author(s):

David M Gibeaut

Keyword(s):

Cell Wall ◽

Nucleotide Sugars ◽

Cell Wall Matrix

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Local differentiation of cell wall matrix polysaccharides in sinuous pavement cells: its possible involvement in the flexibility of cell shape

Plant Biology ◽

10.1111/plb.12681 ◽

2018 ◽

Vol 20 (2) ◽

pp. 223-237 ◽

Cited By ~ 14

Author(s):

P. Sotiriou ◽

E. Giannoutsou ◽

E. Panteris ◽

B. Galatis ◽

P. Apostolakos

Keyword(s):

Cell Wall ◽

Cell Shape ◽

Pavement Cells ◽

Local Differentiation ◽

Cell Wall Matrix

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An extensin peroxidase is associated with white-light inhibition of lupin (Lupinus albus) hypocotyl growth

Functional Plant Biology ◽

10.1071/pp98126 ◽

1999 ◽

Vol 26 (1) ◽

pp. 29 ◽

Cited By ~ 6

Author(s):

P. Jackson ◽

S. Paulo ◽

C. P. P. Ricardo ◽

M. Brownleader ◽

P. O. Freire

Keyword(s):

Cell Wall ◽

White Light ◽

Cell Expansion ◽

Structural Changes ◽

Lupinus Albus ◽

Extension Rate ◽

Hypocotyl Growth ◽

Cross Links ◽

Quantitative Changes

The spatial distribution of the major basic (B2; pI 8.8) peroxidase of the intercellular fluid has an inverse relation with extension rate in etiolated hypocotyls of Lupinus albus L., suggesting its possible role in the control of cell expansion. White-light irradiation of etiolated hypocotyls resulted in growth inhibition and the induction of B2 and acidic (A2, pI 4.7–5.2) isoperoxidases (EC 1.1.11.7) to higher physiological activities. However, only the activities of the B2 isoperoxidases underwent quantitative changes in both space and time which suggested their role in growth-retardation. We have purified the B2 and A2 (pI 5.2) peroxidases to apparent electrophoretic homogeneity. To corroborate evidence obtained elsewhere that growth cessation coincides with cell wall structural changes and cell wall rigidification, we have shown that the B2 peroxidase, and not A2 peroxidase, cross-links tomato extensin in vitro. The B2 peroxidase may therefore catalyse the developmentally and light regulated formation of a covalently cross-linked cell wall extensin matrix in lupin hypocotyls. The cell wall would be more rigid or more recalcitrant to wall-loosening and subsequently contribute to the control of cell expansion.

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