IJS KOLOKVIJ, ponedeljek, 17. 6. 2019, ob 13.00 uri, prof. dr. Stephan Clemens

[Natasa Gosevac]

Vabimo vas na 18. predavanje iz sklopa "Kolokviji na IJS" v letu 2018/19, ki
bo v ponedeljek, 17. junija 2019, ob 13 uri v Veliki predavalnici Instituta
>Jožef Stefan<  na Jamovi cesti 39 v Ljubljani. Napovednik predavanja
najdete tudi na naslovu http://www.ijs.si/ijsw/Koledar_prireditev, posnetke
preteklih predavanj pa na http://videolectures.net/kolokviji_ijs. 

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



prof. dr. Stephan Clemens 

Univerza v Bayreuthu, Bayreuth, Nemčija

 

Na poti do pridelkov z optimalno sestavo mikrohranil

 

Prehodne kovine, kot sta cink (Zn) in železo (Fe), so bistvene za domala
vsak biološki proces. Sedanje ocene npr. kažejo, da je okoli 10% vseh
evkariontskih proteinov odvisnih od Zn. Naše razumevanje načinov
pridobivanja in razporeditve teh mikrohranil pa ostaja omejeno. Rastline
morajo dobiti esencialne mikroelemente iz talne raztopine, v kateri
koncentracija relevantnih ionov lahko variira za več redov velikosti. Težave
ne predstavlja le pomanjkanje, temveč tudi strupenost. Presežek Zn ali
drugih kovinskih ionov, ki močno interagirajo z različnimi komponentami
celic, lahko namreč zavre rast in razvoj. Homeostatični sistem, ki vključuje
transporterje za kovine, kovinske ligande in regulatorne proteine, v
rastlinskih tkivih vzdržuje koncentracijo esencialnih elementov znotraj
razmeroma ozkih fizioloških območij. 

Kot okoljski faktorji za rastline niso relevantni le makro- in
mikroelementi, temveč tudi potencialno zelo strupeni elementi brez biološke
funkcije, npr. kadmij (Cd) in arzen (As). Prisotnost ne-esencialnih
strupenih elementov v okolju je bodisi naravna bodisi posledica
antropogenega onesnaževanja.

Zdravstveno stanje ljudi je v mnogočem odvisno od ionoma rastlin, tj. od
koncentracije esencialnih in ne-esencialnih elementov, predvsem v užitnih
tkivih. Hrana rastlinskega izvora je namreč glavni vir mikrohranil in okoli
tri milijarde ljudi po svetu ogroža pomanjkanje Zn in Fe. Prav tako je
večina Cd in znaten del As, ki pride v naša telesa, posledica uživanja
rastlin. Zato moramo bolje razumeti načine za določanje kopičenja kovin v
rastlinah, mesta in mehanizme kopičenja, kakor tudi kemijsko okolje
elementov, ki v veliki meri vpliva na njihovo biodostopnost. To bo omogočilo
razvoj kmetijskih rastlin z večjimi koncentracijami mikrohranil in mnogo
manj nalaganja ne-esencialnih strupenih elementov.

V našem laboratoriju proučujemo akumulacijo kovin v rastlinah. Pri tem se
osredotočamo na sposobnost določenih rastlinskih vrst, da akumulirajo zelo
veliko Zn in Cd - celo 1000-krat več kot ostale rastline. Naša modelna
rastlina je Arabidopsis halleri, bližnji sorodnik modelne rastline
dvokaličnic (A. thaliana), ki raste v starih rudarskih predelih osrednje
Evrope. Hkrati poskušamo identificirati komponente tolerance za kovine pri
A. thaliana. Ne nazadnje,  raziskujemo še modelni rastlini enokaličnici, to
sta riž in ječmen.

 

Lepo vabljeni!

***********

 

We invite you to the 18th Institute colloquium in the academic year 2018/19.
The colloquium will be held on Monday, June 17, 2019 at 13 PM in the main
Institute lecture hall, Jamova 39, Ljubljana. To read the abstract click
<http://www.ijs.si/ijsw/Koledar_prireditev>
http://www.ijs.si/ijsw/Koledar_prireditev. Past colloquia are posted on
<http://videolectures.net/kolokviji_ijs>
http://videolectures.net/kolokviji_ijs.

********************************************

prof. dr. Stephan Clemens

University of Bayreuth, Bayreuth, Germany

 

Moving towards micronutrient-optimized crops

 

Transition metals such as zinc and iron are essential for virtually every
biological process. For example, current estimates assume that around 10% of
all eukaryotic proteins are zinc-dependent. Our understanding of acquisition
and distribution pathways for these micronutrients, however, is still
limited. Plants have to acquire essential microelements from soil solutions
that can vary in concentrations of the respective ions by orders of
magnitude. Not only deficiency is a threat but also toxicity. An excess of
zinc or other metal ions can inhibit growth due to their tendency to
interact strongly with various cellular components. A homeostatic system
comprising metal transporters, metal ligands and regulatory proteins
maintains the concentrations of essential elements within rather narrow
physiological ranges inside plant tissues. 

Relevant as environmental factors for plants are not only macro- and
microelements, but also potentially highly toxic elements without biological
function, for example cadmium and arsenic. Nonessential toxic elements are
present in the environment either because of natural causes or because of
anthropogenic pollution. 

Human well-being depends in many ways on the ionome of plants, i.e. the
concentrations of essential and nonessential elements especially in edible
tissues. Plant-derived food is a major source of micronutrients and an
estimated three billion people around the world are threatened by zinc or
iron deficiency. Furthermore, most of the human cadmium intake and a large
fraction of the arsenic intake are due to the consumption of plants. Thus,
we need to better understand the pathways determining metal accumulation in
plants, the storage sites and mechanisms as well as the chemical
environment, which greatly influences bioavailability. This will enable the
generation of crops with elevated micronutrient concentrations and much less
accumulation of non-essential, toxic elements. 

We are pursuing different approaches to dissect metal accumulation in
plants. One of them focuses on the ability of certain plant species to
hyperaccumulate zinc and cadmium up to levels more than 1000-fold higher
than in non-hyperaccumulating plants. Our model is Arabidopsis halleri, a
close relative of A. thaliana, and growing in old mining areas in Central
Europe. A second approach is aiming at identifying components of metal
tolerance in A. thaliana. Finally, we are studying the monocot models rice
and barley.

 

Cordially invited!

 

 

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