Navigation Links
Plants recognise pathogenic and beneficial microorganisms
Date:11/1/2012

Plant roots are surrounded by thousands of bacteria and fungi living in the soil and on the root surface. To survive in this diverse environment, plants employ sophisticated detection systems to distinguish pathogenic microorganisms from beneficial microorganisms.

Here the so-called chitin molecules from microorganisms, along with modified versions, play an important role as they are detected by the plant surveillance system. Legumes, for example, build a defence against pathogenic microorganisms in response to simple chitin molecules.

However, when the plant detects a specific modified chitin molecule (called a Nod factor) that is secreted from the rhizobium soil bacteria, formation of new organs in the form of "root nodules" occurs. Rhizobium bacteria are allowed to enter and colonise in these symbiotic organs, and they ultimately produce nitrogen for the plant.

The plants' detection of ligands such as chitin and modified Nod factors takes place through protein receptors that are localised on the surface of cells. Research at the Centre for Carbohydrate Recognition and Signalling (CARB) has now shown that ligand recognition through direct Nod factor binding is a key step in the receptor-mediated signal transduction that leads to root nodule development in legumes.

High-affinity binding was observed in the nano-molar range, comparable to the biologically relevant concentrations where Nod factor has in vivo activity. In contrast to this, simple chitin molecules bind to the receptors with low affinity. Structure-dependent ligand specificity and ligands binding affinities at different receptors may therefore determine which response mechanism is activated in plants exposed to different microbes or microbial communities in the environment.

Interdisciplinary approaches combining advanced biochemistry, chemoselective chemistry and microbial genetics made it possible to investigate the molecular mechanisms involved in distinguishing between Nod factor molecules secreted from rhizobia and chitin secreted by pathogenic microorganisms.

The challenging task of purifying plant receptor proteins, which are present in very low amounts in roots of the model legume Lotus japonicus, was successfully accomplished by expressing the receptors in heterologeous plant-based systems and purifying them from membrane fractions.

Another challenge was the establishment of binding assays with the carbohydrate ligands. Nod factor labelling and Nod factor immobilisation facilitated this, following application of chemoselective chemistry.

The researchers behind the results that have just been published in the international journal PNAS are affiliated with the Danish National Research Foundation's Centre for Carbohydrate Recognition and Signalling at the Department of Molecular Biology and Genetics, Aarhus University (Denmark), Department of Chemistry, University of Copenhagen (Denmark) and Department of Microbiology and Immunology, University of Otago (New Zealand).


'/>"/>

Contact: Jens Stougaard
stougaard@mb.au.dk
45-60-20-26-49
Aarhus University
Source:Eurekalert  

Related biology news :

1. E. coli adapts to colonize plants
2. Plants provide accurate low-cost alternative for diagnosis of West Nile Virus
3. Pitt biologist receives $2 million to study genetic diversity of plants worldwide
4. Scientists uncover mechanism by which plants inherit epigenetic modifications
5. New gene could lead to better bug-resistant plants
6. Researchers use banker plants to help battle whitefly pests
7. Gardeners delight offers glimpse into the evolution of flowering plants
8. No more sneezing, allergen-free house plants
9. No more sneezing, allergen free house plants
10. Plants fungi allies may not help store climate changes extra carbon
11. Plants unpack winter coats when days get shorter
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Plants recognise pathogenic and beneficial microorganisms
(Date:5/9/2016)... UAE, May 9, 2016 Elevay ... comes to expanding freedom for high net worth professionals ... in today,s globally connected world, there is still no ... could ever duplicate sealing your deal with a firm ... passports by taking advantage of citizenship via investment programs ...
(Date:4/28/2016)... -- First quarter 2016:   , Revenues ... first quarter of 2015 The gross margin was 49% ... and the operating margin was 40% (-13) Earnings per ... from operations was SEK 249.9 M (21.2) , Outlook ... 7,000-8,500 M. The operating margin for 2016 is estimated ...
(Date:4/19/2016)... The new GEZE SecuLogic access ... "all-in-one" system solution for all door components. It can ... door interface with integration authorization management system, and thus ... minimal dimensions of the access control and the optimum ... offer considerable freedom of design with regard to the ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... SAN FRANCISCO , June 23, 2016   ... it has secured $1 million in debt financing from ... to ramp up automation and to advance its drug ... for its new facility. "SVB has been ... goes beyond the services a traditional bank would provide," ...
(Date:6/23/2016)... , ... June 23, 2016 , ... STACS DNA Inc., ... Leader at the Arkansas State Crime Laboratory, has joined STACS DNA as a Field ... DNA team,” said Jocelyn Tremblay, President and COO of STACS DNA. “In further expanding ...
(Date:6/23/2016)... , June 23, 2016 Apellis ... Phase 1 clinical trials of its complement C3 ... single and multiple ascending dose studies designed to ... (PD) of subcutaneous injection in healthy adult volunteers. ... (SC) either as a single dose (ranging from ...
(Date:6/23/2016)... Andrew D Zelenetz ... Published recently in Oncology ... touchONCOLOGY, Andrew D Zelenetz , discusses the ... is placing an increasing burden on healthcare systems ... With the patents on many biologics expiring, interest ...
Breaking Biology Technology: