Research Interests.
Energy-rich
molecules produced by photosynthesis feed our planet. The majority
of these substances are moved from the sites of assimilation in the
plants (sources) to distant tissues for growth, energy conversion,
and/or storage (sinks). Photoassimilate translocation in plants
takes place in the phloem. An estimated 90% of the food we consume
has been translocated through this tissue. The phloem is also the
target for an armada of pests such as aphids and leafhoppers, and
plant viruses use it for systemic infection. Therefore the phloem is
of fundamental importance for food security, impact of climate
change on plant performance, and the development of bio-energy
crops. Unfortunately, the complexity of the phloem tissue and the
notorious problems it causes for cell biological investigations have
left us with many open questions regarding its basic functions
including the mechanism of translocation, allocation of assimilates,
and plant pathogen interactions. Our group has developed a variety
of techniques to investigate the secrets of the least understood
major tissue type in plants. Current projects include:
A)
Proteomics of sieve elements.
Sieve elements are the functional
(transporting) units of the phloem. Their cell biology is quite
unique in that they lose many of their organelles including the
nucleus but retain a few specific organelles whose function is
basically unknown. So far, omics approaches have been hampered by
the lack of protocols for sieve element separation from the
neighboring cells. We recently developed a method to isolate sieve
elements, from which we expect major advances in our understanding
of phloem function and protein interactions with plant pathogens.
B) Phloem unloading
The process of phloem unloading allows
plants to generate energy-rich organs such as fruits, storage roots,
cereals, tubers etc., which are our major food sources. The
mechanisms of phloem unloading are poorly understood. We made
significant progress by developing microscopy techniques for in situ
observations of solutes exiting the phloem. We discovered unique
funnel-shaped plasmodesmata which control the exit of solutes.
Currently we work on principles of exit control which in the future
may allow us to direct flow to specific sinks of interest.
C)
Many other interesting things such as:
– engineering of plants
for phytoremediation
– the role of cell wall swelling on plant
cell biology
– the cell biology and physiology of giant kelp
–
any kind of basic principles of plant cell biology / physiology
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