Transcript Volcani

Topic/s number/s:
SFS-2B-2015: Sustainable crop production - Assessing soilimproving cropping systems
Project Description:
Alleviating drought stress: The role of Aquaporins in regulating
hydraulic conductivity in response to drought and ABA in
selected crop species.
Partners search:
UK experts in plant abiotic stress tolerance, especially drought
stress, water and ion channels (aquaporins, transporters);
experts in the evolution of plant drought stress tolerance.
Organization:
Hebrew University of Jerusalem, Institute of Plant Sciences and
Genetics in Agriculture, Faculty of Agriculture, Rehovot
Contact person:
Dr. Menachem Moshelion (Senior Lecturer) – PI
[email protected]
Professor (Emeritus) Arie Altman - [email protected]
The Robert H. Smith Institute of Plant Sciences and Genetics
in Agriculture, and Food and Environment, Rehovot, The
Hebrew University of Jerusalem
Alleviating drought stress tolerance:
The role of Aquaporins in regulating the
bundle sheath and endodermis hydraulic
conductivity in response to drought and ABA
Dr. Menachem Moshelion (Senior Lecturer) – PI
and
Professor (Emeritus) Arie Altman
Abiotic stress tolerance, especially drought and salinity, is
nowadays the single most important trait of relevance to
sustainable crop production.
It is a complex trait to breed for, however solvable in part
The complexity of plant responses to abiotic stress
Stress-associated genes and proteins
Signaling
pathways,
Transcription
Factors
Plant
Breeding
and
Molecular
markers
HSP’s/
chaperones
and LEA
proteins
Ion
and water
transporters,
aquaporins
ROS
scavenging
and
detoxification
Acquired Plant Stress Tolerance
(e.g.QTL’s)
Osmolytes,
Osmoprotectants
Hormones,
Polyamines,
ROS
scavengers
Carbon,
Amino acid,
Fatty acids
metabolism
Genetic
transformation
Other stressresponse
mechanisms
(eg.Apoptosis)
Stress-associated metabolites
Vinocur and Altman (2005) Current
Opinion in Biotechnology
Unique anatomic structure implies the role of two
tissues controlling plant water conductance
The root
endodermis
The shoot
bundle sheath (BS)
BS
)Taiz and Zeiger, 2002(
The main mediators:
Aquaporins – water channels
Trans-membrane water channels proteins which facilitate the transport of
water and/or small neutral solutes (urea, glycerol, boric acid) .
In plants, AQPs are classified into 4 subfamilies (PIPs, TIPs, NIPs, SIPs).
(Maurel C. 2007)
Their function is regulated by several processes, such as gene expression,
protein activity and protein trafficking.
Aquaporins involvement in leaf hydraulic conductance regulation
It is most likely that AQPs evolution across plant species is
of great relevance their water transport efficiency
The radial hydraulic conductivity of the leaf - Kleaf
Kleaf determined as the ratio of water flow rate through the
leaf to the flow driving force.
Kleaf decreases dramatically in response to many
environmental and abiotic stresses. (AQPs involvement).
Logically, the anatomical location of the BS layer should
expose it to long-distance signals coming from the roots.
In dehydrated plants, the concentration of the stress
phytohormone abscisic acid (ABA) progressively increased
in the xylem sap.
BS
Hypothesis
The bundle sheath cells (BSCs) and endodermis
play a key role in controlling leaf and root
hydraulic conductivity (K) in response to ABA
stress signal, going through the vascular system.
Vein ending tracheid
The root
endodermis
Bundle sheath
Mesophyll
)Taiz and Zeiger, 2002(
Objectives
To understand AQPs evolution across relevant crop
plants by:
Characterizing the transcript levels of all (35) aquaporins
expresed in the BSc and endodermis cells under wellirigated and drought conditions.
Characterize their expresssion profile in response to ABA
added directly to the protoplasts.
Examine the BSc and endodermis role in the regulation
of K in response to drought and ABA.
Identify, by silencing, those BSCs AQPs which mediate
Kleaf decrease in response to xylem application of ABA
All experiments are assessed by both genotyping and
phenomics, thus bridging the genotype to phenotype gap
Selected Publications (M. Moshelion et al.)
Sade et. al., (2009) New Phytologist. 181: 651–661.
Shatil-Cohen et. al,.(2011) The Plant Journal 67: 72–80.
And more…