How plantcellcompartments 'chat' witheachother
Central relaystationdiscovered in theinternalcommunication of thalecress
Date:November 4, 2015Source:University of Bonn
Summary:
Scientistshavediscovered a basis of communication in plantcells: The 'MICU' protein controlsthecalciumionconcentration in thecellularpowerstations. Using thesechemicalsignatures, theplantsregulate, forinstance, theformation of organsandreacttowaterstress. Theresultsmay be used in thefutureto optimize agriculturalcrops.
FULL STORY
Thefluorescentsensor protein providesinformation on thecalciumionconcentration in mitochondria in real time. Blue indicateslow, green, mediumandred, highconcentrations.
Credit: Copyright Dr. Stephan Wagner
A team of researchersledbyscientistsfromtheUniversity of Bonn has discovered a basis of communication in plantcells: The 'MICU' protein controlsthecalciumionconcentration in thecellularpowerstations. Using thesechemicalsignatures, theplantsregulate, forinstance, theformation of organsandreacttowaterstress. Theresultsmay be used in thefutureto optimize agriculturalcrops. ThejournalThePlant Cellreports on theresults in itscurrentissue.
Plantsreacttostimulifromtheirenvironmentbyspecificresponses: Ifavailablewaterbecomeslimiting, theycurbevaporationfromtheirleaves. If a pathogenattacks, theyarmthemselveswithchemicalweapons. If a soilfunguswishestocollaboratewith a plantrootformutualbenefit, bothpartnersdiscusstheirduties. "All of thesefineadjustmentsrequire a greatdeal of communicationbetweentheindividualcompartments of theplantcell," says Dr. MarkusSchwarzlaender, principleinvestigator of an EmmyNoethergroup at theInstitute of CropScienceand Resource Conservation at theUniversity of Bonn.
Whenthevariouscomponents of plantcellscommunicatewithanother, they do not usewords but calciumions, i.e. positivelychargedcalciumatoms, instead. "Theinformation is encoded in thefluctuations of thecalciumconcentration of thevariouscellcompartments," explains Dr. Schwarzlaender. How can a singleioncontainandtransducesomuchinformation? This is thequestionscientistshavebeenaskingthemselves since it becameknown how variouscellcompartments 'chat' witheachother.
The 'MICU' protein is a centralrelaystation
Theteam of Dr. Schwarzlaender, togetherwithscientistsfromItaly, France, England, AustraliaandtheMax Planck InstituteforPlantBreedingResearch in CologneandtheUniversity of Muenster, havenowshedlight on thisquestion. Investigatingthecellularpowerstations (mitochondria) of thalecress (Arabidopsisthaliana), thescientistsdiscoveredthatthe 'MICU' protein fulfills a central role in thecontrol of thecalciumionconcentration in themitochondria.
"Inmammals, there is a verysimilar protein whichalsoregulatestheconcentration of calciumions," says Dr. Stephan Wagner fromtheteamworkingwith Dr. Schwarzlaender. Like a turbocharger, it promptsthemitochondria of mammalstoprovidemoreenergy. Thescientistsspeculatedthatthiscould be an interestingcandidate, but theyweretakenbysurprisewhentheyfoundthecloselyrelatedplant-based 'MICU' to be a centralrelaystation in thecommunicationsystem ofArabidopsis. "Thetwo, similarproteins in animalsandplantshaveevidentlyarisenfrom a commonancestor but overthecourse of millennia, theyhavedevelopeddistinctcharacteristics," says Dr. Schwarzlaender.
Fluorescingcellularpowerstationsprovideinformation
Bydestroyingthe gene withthe MICU blueprint in theArabidopsisgenome, theresearcherswereabletoexperimentallyexplorewhatinfluencethe protein has on thecalciumcommunication of theplantcells. Theyequippedthemitochondriawith a fluorescingsensor protein. Using thevariablefluorescenceintensities of thesensor, it waspossibletovisualizechanges in thecalciumconcentrations of thecellularpowerstations in thelivingplants. "Wewereabletoidentify a clearinfluence on thecommunication of themitochondria," reports Dr. Wagner. Knockout of the MICU gene resulted, amongotherconsequences, in modifiedproperties of cellrespiration.
"Withourfindings, wehaveestablished a basisforinfluencingthecalciumsignals in specificparts of theplantcell," Dr. Schwarzlaendersummarizes. SinceArabidopsisis consideredto be an experimental model forplants in general, thefindingsmay be usable in thefutureforoptimizingcrops. Lookingaheadtheresearchersnotethatif, forexample, specificplantscould be taughttoallythemselveswithnitrogen-fixingsoilbacteriaviamodifiedcalciumsignals, a largeamount of fertilizerused in agriculturemay be saved.
Story Source:
Theabove post is reprintedfrommaterialsprovidedbyUniversity of Bonn.Note: Materialsmay be editedforcontentandlength.
Journal Reference:
- Stephan Wagner et al.The EF-Hand Ca2 Binding Protein MICU ChoreographsMitochondrial Ca2 Dynamics in Arabidopsis.ThePlant Cell, 2015 DOI:10.1105/tpc.15.00509