scholarly journals Sugars promote graft union development in the heterograft of cucumber onto pumpkin

2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Li Miao ◽  
Qing Li ◽  
Tian-shu Sun ◽  
Sen Chai ◽  
Changlin Wang ◽  
...  
Keyword(s):  
Sugar Content ◽  
Healing Process ◽  
Energy Charge ◽  
Sugar Metabolism ◽  
Union Formation ◽  
Graft Union ◽  
Positive Role ◽  
Exogenous Glucose ◽  
Expression Of Genes ◽  
Graft Interface

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.

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

2019 ◽  
Vol 19 (1) ◽  
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.

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

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.

scholarly journals Light quality and quantity affect graft union formation of tomato plants

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmed Fathy Yousef ◽  
Muhammad Moaaz Ali ◽  
Hafiz Muhammad Rizwan ◽  
Ahmed Gomaa Gad ◽  
Dangdi Liang ◽  
...  
Keyword(s):  
Vascular Tissue ◽  
Red Light ◽  
Anatomical Study ◽  
Union Formation ◽  
Graft Union ◽  
Tomato Plants ◽  
Light Emitting ◽  
Tomato Seedlings ◽  
Expression Of Genes

AbstractIt is already known that there are many factors responsible for the successful formation of a graft union. However, the role of light has been little studied. In an anatomical study, Scanning Electronic Microscope (SEM) was used to explore the effects of different light-emitting diodes (LEDs) on graft union formation in grafted tomato. In addition, the expression genes related to Auxin hormone signaling pathway (SAUR67, AUX1, ARF30, and LAX3) was investigated. The obtained results showed that the concrescence process occurred faster under R7:B3 light conditions, as compared to blue (B) and white fluorescent (WFL) lights. Red light application caused a delay in the vascular tissue differentiation, which may lead to callus development on both sides, causing junctional failure and resulting in ineffective graft junctional arrangement. The expression of genes related to Auxin hormone significantly increased by R7:B3 application. We suggest that LED spectra affects the graft development of tomato plants and can improve the performance of grafted tomato seedlings.

The Formation of Callus at the Graft Interface in Sitka Spruce

IAWA Journal ◽  
1993 ◽  
Vol 14 (1) ◽  
pp. 13-21 ◽  
Author(s):  
Helen Miller ◽  
J.R. Barnett
Keyword(s):  
Epithelial Cells ◽  
Light Microscopy ◽  
Sitka Spruce ◽  
Picea Sitchensis ◽  
Union Formation ◽  
Graft Union ◽  
Ray Parenchyma ◽  
Ray Cells ◽  
Graft Interface ◽  
Resin Canals

The early stages of graft union formation in Sitka spruce [Picea sitchensis (Bong.) Carr] have been examined using light microscopy in order to determine the origin of callus between the scion and rootstock. All living, undamaged cells exposed to the environment by the process of stern preparation for grafting have been found to be capable of producing callus. The first cells to respond in this way, within two days of grafting, were the epithelial cells of severed resin canals and ray parenchyma exposed where the phloem and xylem of the seion and rootstock were cut through. Fusiform cambium cells near to the graft interface dedifferentiated into callus much later (12-15 days after grafting) by becoming rounded in transverse seetion, and by dividing horizontally to produce a large number of smaller callus cells. Most callus was produced by cells external to the cambium by dedifferentiation and proliferation of ray cells, and of parenchyma associated with severed needle traces.

scholarly journals Identifying Molecular Markers of Successful Graft Union Formation and Compatibility

2020 ◽  
Vol 11 ◽  
Author(s):  
Grégoire Loupit ◽  
Sarah Jane Cookson
Keyword(s):  
Current Knowledge ◽  
Genetic Research ◽  
Transcript Abundance ◽  
Redox Status ◽  
Union Formation ◽  
Graft Union ◽  
Expression Of Genes ◽  
Stress Formation ◽  
Graft Compatibility ◽  
Graft Incompatibility

Grafting is a technique used for millennia for vegetative propagation, especially in perennial fruit crops. This method, used on woody and herbaceous plants, can improve several agronomic characteristics, such as yield or vigor, as well as tolerance to biotic and abiotic stresses. However, some scion/rootstock combinations suffer from poor graft compatibility, i.e., they are unable to form and/or sustain a successful graft union. Identifying symptoms of graft incompatibility is difficult because they are not always present in the first years after grafting and in most cases the causes of incompatibility are still poorly understood. Studies of changes in transcript abundance during graft union formation indicate that grafting responses are similar to responses to wounding and include the differential expression of genes related to hormone signaling, oxidative stress, formation of new vascular vessels, cell development, and secondary metabolites, in particular polyphenols. This review summarizes current knowledge of the changes in transcript abundance, redox status and metabolites accumulation during graft union formation and in cases of graft incompatibility. The goal of this review is to discuss the possibility of identifying marker transcripts, enzyme activities and/or metabolites of grafting success and graft compatibility which could be used to score grafting success for genetic research and in breeding programs. We highlight gaps in current knowledge and potential research directions in this field.

scholarly journals Regulation of sugar metabolism genes in the nitrogen-dependent susceptibility of tomato stems to Botrytis cinerea

2020 ◽  
Vol 127 (1) ◽  
pp. 143-154
Author(s):  
Nathalie Lacrampe ◽  
Félicie Lopez-Lauri ◽  
Raphaël Lugan ◽  
Sophie Colombié ◽  
Jérôme Olivares ◽  
...  
Keyword(s):  
Cell Wall ◽  
Botrytis Cinerea ◽  
Sucrose Synthase ◽  
Nitrogen Availability ◽  
Soluble Sugars ◽  
Plant Defence ◽  
Sugar Metabolism ◽  
Sugar Transporters ◽  
Expression Of Genes ◽  
Underlying Mechanisms

Abstract Background and Aims The main soluble sugars are important components of plant defence against pathogens, but the underlying mechanisms are unclear. Upon infection by Botrytis cinerea, the activation of several sugar transporters, from both plant and fungus, illustrates the struggle for carbon resources. In sink tissues, the metabolic use of the sugars mobilized in the synthesis of defence compounds or antifungal barriers is not fully understood. Methods In this study, the nitrogen-dependent variation of tomato stem susceptibility to B. cinerea was used to examine, before and throughout the course of infection, the transcriptional activity of enzymes involved in sugar metabolism. Under different nitrate nutrition regimes, the expression of genes that encode the enzymes of sugar metabolism (invertases, sucrose synthases, hexokinases, fructokinases and phosphofructokinases) was determined and sugar contents were measured before inoculation and in asymptomatic tissues surrounding the lesions after inoculation. Key Results At high nitrogen availability, decreased susceptibility was associated with the overexpression of several genes 2 d after inoculation: sucrose synthases Sl-SUS1 and Sl-SUS3, cell wall invertases Sl-LIN5 to Sl-LIN9 and some fructokinase and phosphofructokinase genes. By contrast, increased susceptibility corresponded to the early repression of several genes that encode cell wall invertase and sucrose synthase. The course of sugar contents was coherent with gene expression. Conclusions The activation of specific genes that encode sucrose synthase is required for enhanced defence. Since the overexpression of fructokinase is also associated with reduced susceptibility, it can be hypothesized that supplementary sucrose cleavage by sucrose synthases is dedicated to the production of cell wall components from UDP-glucose, or to the additional implication of fructose in the synthesis of antimicrobial compounds, or both.

scholarly journals The Impacts of Tumorigenic and Nontumorigenic Agrobacterium vitis Strains on Graft Strength and Growth of Grapevines

Plant Disease ◽  
2018 ◽  
Vol 102 (2) ◽  
pp. 375-381 ◽  
Author(s):  
Lingyun Hao ◽  
David J. Kemmenoe ◽  
Didem Canik Orel ◽  
Thomas Burr
Keyword(s):  
Crown Gall ◽  
Shoot Growth ◽  
Callus Formation ◽  
Aqueous Suspension ◽  
Water Control ◽  
Agrobacterium Vitis ◽  
Graft Union ◽  
Time Points ◽  
Graft Interface ◽  
Grafting Procedure

The effects of tumorigenic and nontumorigenic strains of Agrobacterium vitis on graft strength and growth of grapevines was studied. A procedure was developed for inoculating graft interface surfaces with A. vitis and for measuring the force required to break grafts at different time points. Cuttings were soaked in an aqueous suspension of bacteria, about 106 CFU/ml, and bacteria were spread onto the graft interface during the grafting procedure. Tumorigenic strain CG49 caused reduced bud germination and increased callus (crown gall) at the graft union and at the base of cuttings at 30 days postinoculation (dpi) and significantly reduced shoot growth by 60 dpi whereas, at the same time points, nontumorigenic strain F2/5 inhibited callus formation but did not affect bud germination or shoot growth. Graft strength was enhanced at 30 dpi with CG49, presumably because the crown gall callus served to secure the union; graft strength was weakened by F2/5 over the same period. Between 30 and 60 dpi, the greatest increase in graft strength was observed in the water control. Following graft union inoculations, the A. vitis population increased more than 1,000-fold within 5 days.

scholarly journals Dehydrins and Soluble Sugars Involved in Cold Acclimation of Rosa wichurana and Rose Cultivar ‘Yesterday’

Horticulturae ◽  
2021 ◽  
Vol 7 (10) ◽  
pp. 379
Author(s):  
Lin Ouyang ◽  
Leen Leus ◽  
Ellen De Keyser ◽  
Marie-Christine Van Labeke
Keyword(s):  
Cold Acclimation ◽  
Cold Hardiness ◽  
Prolonged Exposure ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Soluble Sugars ◽  
Winter Season ◽  
Sugar Metabolism ◽  
Northern Regions ◽  
Cold Hardy

Rose is the most economically important ornamental plant. However, cold stress seriously affects the survival and regrowth of garden roses in northern regions. Cold acclimation was studied using two genotypes (Rosa wichurana and R. hybrida ‘Yesterday’) selected from a rose breeding program. During the winter season (November to April), the cold hardiness of stems, soluble sugar content, and expression of dehydrins and the related key genes in the soluble sugar metabolism were analyzed. ‘Yesterday’ is more cold-hardy and acclimated faster, reaching its maximum cold hardiness in December. R. wichurana is relatively less cold-hardy, only reaching its maximum cold hardiness in January after prolonged exposure to freezing temperatures. Dehydrin transcripts accumulated significantly during November–January in both genotypes. Soluble sugars are highly involved in cold acclimation, with sucrose and oligosaccharides significantly correlated with cold hardiness. Sucrose occupied the highest proportion of total soluble sugars in both genotypes. During November–January, downregulation of RhSUS was found in both genotypes, while upregulation of RhSPS was observed in ‘Yesterday’ and upregulation of RhINV2 was found in R. wichurana. Oligosaccharides accumulated from November to February and decreased to a significantly low level in April. RhRS6 had a significant upregulation in December in R. wichurana. This study provides insight into the cold acclimation mechanism of roses by combining transcription patterns with metabolite quantification.

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