Cell wall degrading enzymes in fusarium wilt of chickpea: correlation between pectinase and xylanase activities and disease development in plants infected with two pathogenic races of Fusarium oxysporum f. sp. ciceris

2006 ◽  
Vol 84 (9) ◽  
pp. 1395-1404 ◽  
Author(s):  
Inmaculada Jorge ◽  
Juan A. Navas-Cortés ◽  
Rafael M. Jiménez-Díaz ◽  
Manuel Tena
Keyword(s):  
Cell Wall ◽  
Fusarium Oxysporum ◽  
Fusarium Wilt ◽  
Specific Activity ◽  
Gel Filtration ◽  
Pectate Lyase ◽  
Disease Development ◽  
In Planta ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes

Production of cell wall degrading enzymes (CWDEs) polygalacturonase (PG), pectate lyase (PL), and xylanase was studied in chickpeas ( Cicer arietinum L. ‘P-2245’) inoculated with Fusarium oxysporum f. sp. ciceris (Padwick) Matuo & K. Sato races 0 (mildly virulent, causing a yellowing syndrome) and 5 (highly virulent, causing a wilting syndrome) by the water-culture method. These CWDEs were similarly produced in both syndromes. PG and PL were the only enzymes occurring in roots and stems and attained the highest specific activity, this being generally higher for race 5 than for race 0. Gel filtration chromatography revealed a similar complement of in planta expressed pectinase isoforms, dominated by an endo-PG and two endo-PLs, the endo-PLs being differentially expressed by the two races. CWDE activities in roots and stems were positively correlated with development of yellowing and wilting. Exceptions to this were PG in stems, which was negatively correlated with the development of yellowing, and PG in roots, which showed a negative trend with development of either syndrome. The levels of CWDEs that significantly correlated with disease development were adequately described by exponential functions of disease progress. Results have implications for the role played by CWDEs in the early and later stages of pathogenesis in chickpea fusarium wilt.

Effect of the herbicide Pyradur on host cell wall degradation by the sugarbeet pathogens Rhizoctonia solani and Sclerotium rolfsii

1996 ◽  
Vol 74 (9) ◽  
pp. 1407-1415 ◽  
Author(s):  
Mohamed S. El-Abyad ◽  
Amira M. Abu-Taleb ◽  
Tarek Abdel-Mawgood
Keyword(s):  
Cell Wall ◽  
Rhizoctonia Solani ◽  
Sclerotium Rolfsii ◽  
Pectate Lyase ◽  
Inoculum Potential ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes ◽  
Alkaline Conditions

Pyradur applied to soil at 0.6–2.4 µg∙g−1 active ingredients suppressed infection of three sugarbeet cultivars by Rhizoctonia solani and Sclerotium rolfsii. In the absence of Pyradur, R. solani was more virulent than S. rolfsii against 'Raspoly' and 'TOP', whereas S. rolfsii was more virulent than R. solani against ‘Tribel’. Virulence was directly correlated with the activities of cell wall degrading enzymes produced by mese pathogens in vivo and on cell walls in vitro. Reduced virulence of R. solani and S. rolfsii under Pyradur stress was due to decreased inoculum potential of the two pathogens at the utilized concentrations of herbicide in situ and to reduced production of cell wall degrading enzymes in vitro and in host tissues. In addition, shifts in the pH of cell wall amended media, because of changes in the nature of metabolic products of the pathogens under Pyradur stress, suggest possible repression or stimulation of the activity of the enzymes involved in degradation in vivo, of which cellulase and polygalacturonase are favoured by acid conditions, and galactanase, mannase, and pectate lyase are favoured by alkaline conditions. Keywords: sugarbeet, Rhizoctonia solani, Sclerotium rolfsii, Pyradur, metolachlor, chloridazon, growth activities, pathogenicity, virulence, cell wall enzymes.

scholarly journals The role of L-arabinose metabolism for Escherichia coli O157:H7 in edible plants

2021 ◽  
Author(s):  
Louise Emma Crozier ◽  
Jacqueline Marshall ◽  
Ashleigh Holmes ◽  
Kathryn Wright ◽  
Yannick Rossez ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Cell Wall ◽  
Escherichia Coli O157 ◽  
In Planta ◽  
Cell Wall Degrading Enzymes ◽  
Cell Wall Polysaccharides ◽  
E Coli ◽  
Degrading Enzymes ◽  
Food Borne

Arabinose is a major plant aldopentose in the form of arabinans complexed in cell wall polysaccharides or glycoproteins (AGP), but comparatively rare as a monosaccharide. L-arabinose is an important bacterial metabolite, accessed by pectolytic microorganisms such as Pectobacterium atrosepticum via pectin and hemicellulose degrading enzymes. However, not all plant-associated microbes encode cell wall degrading enzymes, yet can metabolise L-arabinose, raising questions about their use of and access to the glycan in plants. Therefore, we examined L-arabinose metabolism in the food-borne pathogen Escherichia coli O157:H7 (isolate Sakai) during its colonisation of plants. L-arabinose metabolism (araBA) and transport (araF) genes were activated at 18 C in vitro by L-arabinose and expressed over prolonged periods in planta. Although deletion of araBAD did not impact the colonisation ability of E. coli O157:H7 (Sakai) on plants, araA was induced on exposure to spinach cell wall polysaccharides. Furthermore, debranched and arabinan oligosaccharides induced ara metabolism gene expression in vitro, and stimulated modest proliferation, while immobilised pectin did not. Thus, E. coli O157:H7 (Sakai) can utilise pectin/AGP-derived L-arabinose as a metabolite, but differs fundamentally in ara gene organisation, transport and regulation from the related pectinolytic species P. atrosepticum, reflective of distinct plant-associated lifestyles.

scholarly journals Computational proteomics analysis reveals pathogen secreted carbohydrate active enzymes in tomato xylem sap

2021 ◽  
Author(s):  
Abhijeet Roy ◽  
Barsha Kalita ◽  
Aiswarya Jayaprakash ◽  
Annamalai Arunachalam ◽  
Lakshmi PTV
Keyword(s):  
Cell Wall ◽  
Tomato Plant ◽  
Xylem Sap ◽  
In Planta ◽  
Cell Wall Degrading Enzymes ◽  
Carbohydrate Active Enzymes ◽  
Causal Organism ◽  
Degrading Enzymes ◽  
Susceptible Tomato

Abstract Fusarium oxysporum f. sp. lycopersici (Fol), a causal organism of Fusarium wilt in the tomato plant, secretes cell wall degrading enzymes, also known as carbohydrate-active enzymes (CAZymes). These are crucial during colonization and pathogenesis, as evidenced by several proteomic studies, revealing the importance of these CAZymes in virulence and pathogenicity. However, few of them have been done in-planta, exhibiting differences in the expression of these cell wall degrading enzymes compared to in-vitro studies. Therefore, to explore the CAZymes involved in pathogenesis while residing in the host plant, an in-planta (xylem sap) proteomics of a susceptible tomato variety affected with Fol was done. Most of these CAZymes belonged to the hydrolase and oxidoreductase families having no significant homology with tomato proteins. Nearly 90% of them were predicted to be soluble and extracellular. The core CAZymes families with interactional evidence identified were AA3, GH3, GH18, GH20, GH28, GH43, GH47, GH55 and CE8. Thus, apart from annotating some of the hypothetical proteins to be CAZymes, the study sheds light on CAZymes families that may have a role in the pathogenesis and survival of this fungus in the susceptible tomato plant.

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