The Effect of Water Channels on
Germination and Seedling Growth
Charlotte Carroll1, Dr Lorenzo Frigerio1, Prof Bill Finch-Savage2
1School
of Life Sciences, Gibbet Hill Campus, The University of Warwick, Coventry, CV4 7AL, United Kingdom
2School of Life Sciences, Wellesbourne Campus, The University of Warwick, Wellesbourne, Warwick, CV35 9EF United Kingdom
Introduction
• Cell membranes contain proteins, for example water channels
Vacuole
Membrane
• Water channels transport water and solutes across cell membranes(1)
• Water channels at the vacuole membrane are called Tonoplast Instrinsic Proteins (TIP)
• We work on Arabidopsis thaliana, which has 10 types of TIP(2)
Arabidopsis Thaliana Plants
• TIP3 are found in the seed embryo and TIP1;1 in all adult tissues
THE PLANT CELL
Aim
The Global
Drought Monitor
May 2013
• To study TIP3 and roles in seedling growth, specifically in water stress conditions
Provided by UCL
Department of
Space and
Climate Physics
• TIP3 could be a future target for drought resistant crop development
• 68,939,000 people were affected by ‘Exceptional Drought’ in May 2013
Germination
• TIP3 locates to both tonoplast AND cell
Germination Rate
membrane(3)
Water Stress
Low
Med
• TIP3 could be responsible for water uptake in germinating seeds
High
• We measured Germination Rate of seeds
from genetically modified plants
• In different water stress conditions
TIP3 tagged with Yellow
Fluorescent Protein (YFP),
imaged with Confocal
Microscopy. Scale Bar 10µm.
• Germination rate is significantly different
between seed types at each stress level
(P=0.002)
Growth
Wild
Type
Wild-Type
‘LOTS more TIP3’ tagged
with YFP
More
moreTIP1;1
TIP1;1
More
more TIP3
LOTSmore
moreTIP3
TIP3
LOTS
Germination Rate decreases in seeds with a higher amount of TIP3,
but it is similar in each water stress condition
Water Stress
Seedling Growth
• We measured Seedling length as a
measure of Growth from the same
seeds
Low
Med
High
• Seedlings were transferred to water
stress conditions post-germination and
measured at 3 weeks old
Left to right: Two ‘more TIP3’
seedlings, two ‘Wild Type’ and
two ‘LOTS more TIP3’
Cellular level using YFP. Scale
Bar 20µm. Left: ‘LOTS more
TIP3’ Right: ‘more TIP3’
• Mean seedling length is significantly
different between plant types at each
stress level (P=0.03)
Wild-Type
Wild Type
more
More TIP1;1
moreTIP3
TIP3
More
LOTSmore
moreTIP3
TIP3
LOTS
Seedling Growth is limited by water stress, and high amounts of TIP3.
Conclusions and Future Work
More
• ‘More TIP3’ enhances seedling growth and ‘LOTS more TIP3’ reduces germination rate and seedling growth
• Increased TIP3 could enhance drought resistance but only if a certain amount is present
• We would now like to study the effect of less TIP3 on germination rate and seedling length.
• These experiments could be repeated in crops to evaluate drought tolerance.
Acknowledgements
Thank you to my supervisors and lab colleagues past and present for resources, guidance, and encouragement.
(1) Johanson U, Karlsson M, Johansson I, Gustavsson S, Sjovall S, Fraysse L, Weig AR, KjellbomJ P (2001) The complete set of genes encoding (2) Gattolin S, Sorieul M, Hunter PR, Khonsari R, Frigerio L (2009) Expression mapping of the tonoplast intrinsic protein family in Arabidopsis
major intrinsic proteins in Arabidopsis provides a framework for new nomenclature for major intrinsic proteins in plant. Plant Physiology
root tissues BMC Plant Biology 9:1333
126:1358-1369
(3) Gattolin S, Sorieul M, Frigerio L (2011) Mapping of tonoplast intrinsic proteins in maturing and germinating Arabidopsis seeds reveals
dual localization of embryonic TIPs to the tonoplast and plasma membrane. Molecular Plant 4,1:180-189