scholarly journals Mechanisms Underlying Graft Union Formation and Rootstock Scion Interaction in Horticultural Plants

2020 ◽  
Vol 11 ◽  
Author(s):  
Aatifa Rasool ◽  
Sheikh Mansoor ◽  
K. M. Bhat ◽  
G. I. Hassan ◽  
Tawseef Rehman Baba ◽  
...  

Grafting is a common practice for vegetative propagation and trait improvement in horticultural plants. A general prerequisite for successful grafting and long term survival of grafted plants is taxonomic proximity between the root stock and scion. For the success of a grafting operation, rootstock and scion should essentially be closely related. Interaction between the rootstock and scion involves complex physiological-biochemical and molecular mechanisms. Successful graft union formation involves a series of steps viz., lining up of vascular cambium, generation of a wound healing response, callus bridge formation, followed by vascular cambium formation and subsequent formation of the secondary xylem and phloem. For grafted trees compatibility between the rootstock/scion is the most essential factor for their better performance and longevity. Graft incompatibility occurs on account of a number of factors including of unfavorable physiological responses across the graft union, transmission of virus or phytoplasma and anatomical deformities of vascular tissue at the graft junction. In order to avoid the incompatibility problems, it is important to predict the same at an early stage. Phytohormones, especially auxins regulate key events in graft union formation between the rootstock and scion, while others function to facilitate the signaling pathways. Transport of macro as well as micro molecules across long distances results in phenotypic variation shown by grafted plants, therefore grafting can be used to determine the pattern and rate of recurrence of this transport. A better understanding of rootstock scion interactions, endogenous growth substances, soil or climatic factors needs to be studied, which would facilitate efficient selection and use of rootstocks in the future. Protein, hormones, mRNA and small RNA transport across the junction is currently emerging as an important mechanism which controls the stock/scion communication and simultaneously may play a crucial role in understanding the physiology of grafting more precisely. This review provides an understanding of the physiological, biochemical and molecular basis underlying grafting with special reference to horticultural plants.

Development ◽  
2000 ◽  
Vol 127 (15) ◽  
pp. 3197-3204 ◽  
Author(s):  
K. Koizumi ◽  
M. Sugiyama ◽  
H. Fukuda

For the genetic analysis of molecular mechanisms underlying temporal and spatial regulation of vascular pattern formation, we isolated mutants of Arabidopsis thaliana that are impaired in vascular patterning. Microscopic examination of the cotyledonary venation of 3,400 M(3) lines led to the identification of 12 mutant lines. Genetic analysis of 8 of these mutant lines indicated that vein pattern formation in these lines resulted from monogenic recessive mutations in 7 different genes, designated VAN1 through VAN7. Mutations in VAN1 through VAN6 genes caused fragmentation (disconnection or partial loss) of lateral veins of the cotyledon and tertiary veins of the rosette leaf whereas they were less injurious to the formation of major veins. Detailed characterization of the van3 mutant using pAthb8::GUS and pTED3::GUS, as molecular markers for the early stage of vascular tissue formation showed that the provascular tissue of the cotyledonary lateral veins was differentiated in fragments during late embryogenesis. These phenotypes of the van mutants are discussed in relation to the auxin signal flow canalization hypothesis and the diffusion-reaction prepattern hypothesis, with the fragility of the continuity in the minor vein formation favoring the latter hypothesis.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Ahmed Fathy Yousef ◽  
Muhammad Moaaz Ali ◽  
Hafiz Muhammad Rizwan ◽  
Ahmed Gomaa Gad ◽  
Dangdi Liang ◽  
...  

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.


2020 ◽  
Vol 14 ◽  
Author(s):  
Subhajit Makar ◽  
Abhrajyoti Ghosh ◽  
Divya ◽  
Shalini Shivhare ◽  
Ashok Kumar ◽  
...  

: Despite advances in the development of cytotoxic and targeted therapies, pancreatic adenocarcinoma (PAC) remains a significant cause of cancer mortality worldwide. It is also difficult to detect it at an early stage due to numbers of factors. Most of the patients are present with locally advanced or metastatic disease, which precludes curative resection. In the absence of effective screening methods, considerable efforts have been made to identify better systemic treatments during the past decade. This review describes the recent advances in molecular mechanisms involved in pancreatic cancer initiation, progression, and metastasis. Additionally, the importance of deregulated cellular signalling pathways and various cellular proteins as potential targets for developing novel therapeutic strategies against incurable forms of pancreatic cancer is reported. The emphasis is on the critical functions associated with growth factors and their receptors viz. c-MET/HGF, CTHRC1, TGF-β, JAK-STAT, cyclooxygenase pathway, WNT, CCK, MAPK-RAS-RAF, PI3K-AKT, Notch, src, IGF-1R, CDK2NA and chromatin regulation for the sustained growth, survival, and metastasis of pancreatic cancer cells. It also includes various therapeutic strategies viz. immunotherapy, surgical therapy, radiation therapy and chemotherapy.


Cancers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 3730
Author(s):  
Berend R. Beumer ◽  
Roeland F. de Wilde ◽  
Herold J. Metselaar ◽  
Robert A. de Man ◽  
Wojciech G. Polak ◽  
...  

For patients presenting with hepatocellular carcinoma within the Milan criteria, either liver resection or liver transplantation can be performed. However, to what extent either of these treatment options is superior in terms of long-term survival is unknown. Obviously, the comparison of these treatments is complicated by several selection processes. In this article, we comprehensively review the current literature with a focus on factors accounting for selection bias. Thus far, studies that did not perform an intention-to-treat analysis conclude that liver transplantation is superior to liver resection for early-stage hepatocellular carcinoma. In contrast, studies performing an intention-to-treat analysis state that survival is comparable between both modalities. Furthermore, all studies demonstrate that disease-free survival is longer after liver transplantation compared to liver resection. With respect to the latter, implications of recurrences for survival are rarely discussed. Heterogeneous treatment effects and logical inconsistencies indicate that studies with a higher level of evidence are needed to determine if liver transplantation offers a survival benefit over liver resection. However, randomised controlled trials, as the golden standard, are believed to be infeasible. Therefore, we suggest an alternative research design from the causal inference literature. The rationale for a regression discontinuity design that exploits the natural experiment created by the widely adopted Milan criteria will be discussed. In this type of study, the analysis is focused on liver transplantation patients just within the Milan criteria and liver resection patients just outside, hereby ensuring equal distribution of confounders.


2002 ◽  
Vol 12 (3) ◽  
pp. 290-298 ◽  
Author(s):  
M Graflund ◽  
B Sorbe ◽  
M Karlsson

Abstract.Graflund M, Sorbe B, Karlsson M. Immunohistochemical expression of p53, bcl-2, and p21 WAF1/CIP1 in early cervical carcinoma: Correlation with clinical outcome.The objective of this study was to assess the value of p53, bcl-2, and p21WAF1/CIP1 immunoreactivity as predictors of pelvic lymph node metastases (LNM), recurrences, and death due to the disease in early stage (FIGO I-II) cervical carcinomas. FIGO stage, type of histopathology, and tumor grade were also evaluated in this series of patients treated by radical hysterectomy (Wertheim-Meigs) between 1965 and 1990. A total of 172 patients were included. A tumor was regarded as positive when more than 30% of the neoplastic cells exhibited immunoreactivity. Positive immunostaining was found in 8.9% for p53, in 43.5% for bcl-2, and in 25.0% for p21WAF1/CIP1. None of them was able to predict LNM or clinical outcome. Presence of LNM, tumor recurrence, and death from disease were significantly associated with the FIGO stage (P = 0.014, P = 0.009, and P = 0.001, respectively). The 5-year cancer-specific survival rate was 91.6% and the overall survival rate was 90.5%. It was concluded that immunohistochemically detected p53, bcl-2, and p21WAF1/CIP1 appeared to be of no predictive value with regard to LNM, tumor recurrences, or long-term survival in early cervical carcinomas.


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 9 (1) ◽  
Author(s):  
Fan Xia ◽  
Yonju Ha ◽  
Shuizhen Shi ◽  
Yi Li ◽  
Shengguo Li ◽  
...  

AbstractThe retina, as the only visually accessible tissue in the central nervous system, has attracted significant attention for evaluating it as a biomarker for neurodegenerative diseases. Yet, most of studies focus on characterizing the loss of retinal ganglion cells (RGCs) and degeneration of their axons. There is no integrated analysis addressing temporal alterations of different retinal cells in the neurovascular unit (NVU) in particular retinal vessels. Here we assessed NVU changes in two mouse models of tauopathy, P301S and P301L transgenic mice overexpressing the human tau mutated gene, and evaluated the therapeutic effects of a tau oligomer monoclonal antibody (TOMA). We found that retinal edema and breakdown of blood–retina barrier were observed at the very early stage of tauopathy. Leukocyte adhesion/infiltration, and microglial recruitment/activation were constantly increased in the retinal ganglion cell layer of tau transgenic mice at different ages, while Müller cell gliosis was only detected in relatively older tau mice. Concomitantly, the number and function of RGCs progressively decreased during aging although they were not considerably altered in the very early stage of tauopathy. Moreover, intrinsically photosensitive RGCs appeared more sensitive to tauopathy. Remarkably, TOMA treatment in young tau transgenic mice significantly attenuated vascular leakage, inflammation and RGC loss. Our data provide compelling evidence that abnormal tau accumulation can lead to pathology in the retinal NVU, and vascular alterations occur more manifest and earlier than neurodegeneration in the retina. Oligomeric tau-targeted immunotherapy has the potential to treat tau-induced retinopathies. These data suggest that retinal NVU may serve as a potential biomarker for diagnosis and staging of tauopathy as well as a platform to study the molecular mechanisms of neurodegeneration.


2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Ying Zhu ◽  
Wen Xu ◽  
Wei Hu ◽  
Fang Wang ◽  
Yan Zhou ◽  
...  

Abstract Background Portal hypertension induced esophageal and gastric variceal bleeding is the main cause of death among patients of decompensated liver cirrhosis. Therefore, a standardized, biomarker-based test, to make an early-stage non-invasive risk assessment of portal hypertension, is highly desirable. However, no fit-for-purpose biomarkers have yet been identified. Methods We conducted a pilot study consisting of 5 portal hypertensive gastropathy (PHG) patients and 5 normal controls, sampling the gastric mucosa of normal controls and PHG patients before and after endoscopic cyanoacrylate injection, using label-free quantitative (LFQ) mass spectrometry, to identify potential biomarker candidates in gastric mucosa from PHG patients and normal controls. Then we further used parallel reaction monitoring (PRM) to verify the abundance of the targeted protein. Results LFQ analyses identified 423 significantly differentially expressed proteins. 17 proteins that significantly elevated in the gastric mucosa of PHG patients were further validated using PRM. Conclusions This is the first application of an LFQ-PRM workflow to identify and validate PHG–specific biomarkers in patient gastric mucosa samples. Our findings lay the foundation for comprehending the molecular mechanisms of PHG pathogenesis, and provide potential applications for useful biomarkers in early diagnosis and treatment. Trial registration and ethics approval: Trial registration was completed (ChiCTR2000029840) on February 25, 2020. Ethics Approvals were completed on July 17, 2017 (NYSZYYEC20180003) and February 15, 2020 (NYSZYYEC20200005).


2021 ◽  
Vol 9 (2) ◽  
pp. 385 ◽  
Author(s):  
Zongmin Liu ◽  
Lingzhi Li ◽  
Qianwen Wang ◽  
Faizan Ahmed Sadiq ◽  
Yuankun Lee ◽  
...  

Biofilm formation has evolved as an adaptive strategy for bacteria to cope with harsh environmental conditions. Currently, little is known about the molecular mechanisms of biofilm formation in bifidobacteria. A time series transcriptome sequencing analysis of both biofilm and planktonic cells of Bifidobacterium longum FGSZY16M3 was performed to identify candidate genes involved in biofilm formation. Protein–protein interaction network analysis of 1296 differentially expressed genes during biofilm formation yielded 15 clusters of highly interconnected nodes, indicating that genes related to the SOS response (dnaK, groS, guaB, ruvA, recA, radA, recN, recF, pstA, and sufD) associated with the early stage of biofilm formation. Genes involved in extracellular polymeric substances were upregulated (epsH, epsK, efp, frr, pheT, rfbA, rfbJ, rfbP, rpmF, secY and yidC) in the stage of biofilm maturation. To further investigate the genes related to biofilm formation, weighted gene co-expression network analysis (WGCNA) was performed with 2032 transcript genes, leading to the identification of nine WGCNA modules and 133 genes associated with response to stress, regulation of gene expression, quorum sensing, and two-component system. These results indicate that biofilm formation in B. longum is a multifactorial process, involving stress response, structural development, and regulatory processes.


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