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

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.

2016 ◽  
Vol 82 (18) ◽  
pp. 5542-5552 ◽  
Author(s):  
Hanna Faist ◽  
Alexander Keller ◽  
Ute Hentschel ◽  
Rosalia Deeken

ABSTRACTCrown gall disease of grapevine is caused by virulentAgrobacteriumstrains and establishes a suitable habitat for agrobacteria and, potentially, other bacteria. The microbial community associated with grapevine plants has not been investigated with respect to this disease, which frequently results in monetary losses. This study compares the endophytic microbiota of organs from grapevine plants with or without crown gall disease and the surrounding vineyard soil over the growing seasons of 1 year. Amplicon-based community profiling revealed that the dominating factor causing differences between the grapevine microbiota is the sample site, not the crown gall disease. The soil showed the highest microbial diversity, which decreased with the distance from the soil over the root and the graft union of the trunk to the cane. Only the graft union microbiota was significantly affected by crown gall disease. The bacterial community of graft unions without a crown gall hosted transient microbiota, with the three most abundant bacterial species changing from season to season. In contrast, graft unions with a crown gall had a higher species richness, which in every season was dominated by the same three bacteria (Pseudomonassp.,Enterobacteriaceaesp., andAgrobacterium vitis). Forin vitro-cultivated grapevine plantlets,A. vitisinfection alone was sufficient to cause crown gall disease. Our data show that microbiota in crown galls is more stable over time than microbiota in healthy graft unions and that the microbial community is not essential for crown gall disease outbreak.IMPORTANCEThe characterization of bacterial populations in animal and human diseases using high-throughput deep-sequencing technologies, such as 16S amplicon sequencing, will ideally result in the identification of disease-specific microbiota. We analyzed the microbiota of the crown gall disease of grapevine, which is caused by infection with the bacterial pathogenAgrobacterium vitis.All otherAgrobacteriumspecies were found to be avirulent, even though they lived together withA. vitisin the same crown gall tumor. As has been reported for human cancer, the crown gall tumor also hosted opportunistic bacteria that are adapted to the tumor microenvironment. Characterization of the microbiota in various diseases using amplicon sequencing may help in early diagnosis, to serve as a preventative measure of disease in the future.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Li Miao ◽  
Qing Li ◽  
Tian-shu Sun ◽  
Sen Chai ◽  
Changlin Wang ◽  
...  

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.


2019 ◽  
Vol 19 (1) ◽  
Author(s):  
Duyên Prodhomme ◽  
Josep Valls Fonayet ◽  
Cyril Hévin ◽  
Céline Franc ◽  
Ghislaine Hilbert ◽  
...  

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.


2021 ◽  
Vol 8 (1) ◽  
Author(s):  
Longmei Zhai ◽  
Xiaomin Wang ◽  
Dan Tang ◽  
Qi Qi ◽  
Huseyin Yer ◽  
...  

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.


1984 ◽  
Vol 62 (7) ◽  
pp. 1393-1397 ◽  
Author(s):  
M. D. Zhou ◽  
T. T. Lee

The callus-promoting activity of most commonly known as well as some rarely tested auxins was compared with that of 2,4-dichlorophenoxyacetic acid (2,4-D) for in vitro culture of the excised embryo of spring and winter wheat (Triticum aestivum L.), cv. Chinese Spring and cv. Fredrick. Different auxins in a concentration range from 1 to 50 μM showed widely different activities. Also the two wheat cultivars responded differently to the auxins. When rapid callus formation with limited root growth was used as the basis for comparison, 2-(2-methyl-4-chlorophenoxy)propionic acid (2-MCPP), α-naphthaleneacetic acid, 3,6-dichloro-2-methoxybenzoic acid (dicamba), 4-amino-3,5,6,trichloropicolinic acid (picloram), γ-(2,4-dichlorophenoxy)butyric acid, 2,4,5-trichlorophenoxyacetic acid, and 2,4,5-trichlorophenoxypropionic acid, in the order of effectiveness, were superior to 2,4,-D for callus induction from the embryo of 'Chinese Spring,' although the concentration required was higher than that of 2,4-D. For the winter wheat 'Fredrick,' however, only picloram, dicamba, and 2-MCPP performed as well as 2,4-D. All auxins tested promoted shoot growth; 2-methyl-4-chlorophenoxypropionic acid was most effective for 'Chinese Spring,' whereas picloram was most effective for 'Fredrick.'


Plant Disease ◽  
1998 ◽  
Vol 82 (12) ◽  
pp. 1288-1297 ◽  
Author(s):  
Thomas J. Burr ◽  
Carlo Bazzi ◽  
Sandor Süle ◽  
Leon Otten

1998 ◽  
Vol 11 (8) ◽  
pp. 836-838 ◽  
Author(s):  
J.-Y. Salomone ◽  
E. Szegedi ◽  
P. Cobanov ◽  
L. Otten

Crown gall on grapevine is mainly caused by Agrobacterium vitis, which metabolizes tartrate. Competition experiments between a tartrate-utilizing strain and its non-utilizing derivative showed that tartrate utilization confers a selective advantage on grapevine.


Author(s):  
Zhenghai Mo ◽  
Gang Feng ◽  
Wenchuan Su ◽  
Zhuangzhuang Liu ◽  
Fangren Peng

Pecan (Carya illinoinensis), as a popular nut tree, is widely planted in China in recent years. Grafting is an important technique for its cultivation. For a successful grafting, graft union development generally involves the formation of callus and vascular bundles at the graft union. To explore the molecular mechanism of graft union development, we applied high through-put RNA sequencing to investigate transcriptomic profiles of graft union at four time points (0d, 8d, 15d, and 30d) during pecan grafting process. We identified a total of 12,180 differentially expressed genes. In addition, we found that the content of auxin, cytokinin and gibberellin were accumulated at the graft unions during the grafting process. Correspondingly, genes involved in those hormone signaling were found to be differentially expressed. Interestingly, we found that most genes associated with cell division were up-regulated at callus formative stages, while genes related to cell elongation, secondary cell wall deposition, and programmed cell death were generally up-regulated at vascular bundle formative stages. In the meantime, genes responsible for reactive oxygen species were highly up-regulated across the graft union developmental process. These results will aid in our understanding of successful grafting in the future.


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