Morrris Lab @BGSU
Our long-term goal is to identify the molecular basis of how plant cells sense and respond to changes in the concentrations of polyamines and polyamine conjugates. Our hypothesis is that polyamines are regulated by compartmentation within the cell, and therefore transporters play an essential role in polyamine homeostasis.
A new pathway for putrescine synthesis in plants.
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In our 2017 Plant Science paper, we describe a new pathway for putrescine synthesis in plants involving the enzymes ADC2 and ARGAH2. Since all ARGAH enzymes in plants are highly conserved and ARGAH1 also has agmatinase activity. the mitochondria may also be a second site for putrescine biosynthesis.
Altered expression of PUT5 affects flowering
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PUT5 is localized to the ER. put5 plants flower four days ealier than WT plants but plants overexpressing a PUT that is localized to the ER flower 14-17 later. A similar delay of flowering was noted for transgenic plants overexpressing PUT transporter that was localized to the chloroplast.
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Increased expression of these PUT transporters also resulted in plants having larger leaves, thicker floral stems, and more flowers. Consitutive expression of these PUTS was associated with an extreme delay of senescence.
ER is a storage site for polyamines
​In Ahmed et al. (2017) we show that a polyamine transporter in A. thaliana and another in rice are localized to the ER. Thus polyamines can be sequestered form the cytoplasm by PUTs. This has important implications for polyamine signaling as we describe in this paper.
Polyamine Synthesis and Metabolism in Plants
