1. Front Cover.cdr - CORE
1. Front Cover.cdr - CORE
1. Front Cover.cdr - CORE
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A B S T R A C T B O O K – A B S T R A C T S O F P O S T E R S<br />
Arabidopsis RNA polymerase II (RNAPII) C-terminal domain (CTD) phosphatases regulate stress-responsive<br />
gene expression and plant development via the dephosphorylation of serine (Ser) residues of the CTD.<br />
Some of these phosphatases (CTD phosphatase-like 1 (CPL1) to CPL3) negatively regulate ABA and stress<br />
responses.<br />
We isolated AtCPL5, a cDNA encoding a protein containing two CTD phosphatase domains (CPDs). To<br />
characterize AtCPL5, we analyzed the gene expression patterns and subcellular protein localization,<br />
investigated various phenotypes of AtCPL5-overexpressors and knockout mutants involved in ABA and<br />
drought responses, performed microarray and RNA hybridization analyses using AtCPL5-overexpressors,<br />
and assessed the CTD phosphatase activities of the purified AtCPL5 and each CPD of the protein.<br />
Transcripts of the nucleus-localized AtCPL5 were induced by ABA and drought. AtCPL5-overexpressors<br />
exhibited ABA-hypersensitive phenotypes (increased inhibition of seed germination, seedling growth, and<br />
stomatal aperture), lower transpiration rates upon dehydration, and enhanced drought tolerance, while the<br />
knockout mutants showed weak ABA hyposensitivity. AtCPL5 overexpression changed the expression of<br />
numerous genes, including those involved in ABA-mediated responses. In contrast to Ser-5-specific<br />
phosphatase activity of the negative stress response regulators, purified AtCPL5 and each CPD of the<br />
protein specifically dephosphorylated Ser-2 in RNAPII CTD. We conclude that AtCPL5 is a unique CPL family<br />
protein that positively regulates ABA-mediated development and drought responses in Arabidopsis.<br />
CALLUS INDUCTION AND FATTY ACID PROFILES OF JATROPHA CURCAS INDUCED CALLI<br />
ChongSiang Tee 1 , ThenSoong Siow 1 , Adelin Ting Su Yien 2<br />
1 Department of Biological Science, Faculty of Science, Universiti Tunku Abdul Rahman, Jalan Universiti, Bandar Barat, Kampar, Perak, Malaysia<br />
2 School of Science, Monash University, Jalan Lagoon Selatan, Bandar Sunway, Selangor Darul Ehsan, Malaysia.<br />
E-mail: teecs@utar.edu.my<br />
Jatropha curcas, a biodiesel production plant, is intensively cultivated in many countries. The main<br />
objectives of this study were to induce callus from various types of J. curcas explants and study the fatty<br />
acid content of the induced calli. In this study, different types of auxins at various concentrations were used<br />
to induce callus. In addition, fatty acid compositions and total oil content in the induced calli were also<br />
investigated. It was observed that 4 µM of picloram, 4 µM of dicamba and 2 µM of 2,4-D, cotyledon and<br />
petioles explants, respectively. For leaf explants, 2,4-D was used in combination with cytokinin to induce<br />
callus. Besides, embryogenic calli induced from cotyledon explants using MS medium containing 4 µM<br />
dicamba. The fatty acid analysis revealed that fatty acid compositions in the induced calli were similar to<br />
that of seed kernels particularly the fatty acid profile of embryogenic calli. Generally, induced calli had lower<br />
oil content than seed kernels. Among all types of induced calli studied, embryogenic calli had higher total oil<br />
content than non- embryogenic calli but significantly lower than the seed kernels.<br />
NEW PERSPECTIVE IN PLANT VITAMIN D PRODUCTION<br />
Daniele Silvestro 1 , Christina Fredslund 1 , Rie Bak Jäpelt 2 , Poul Erik Jensen 1<br />
1 Department of Plant Biology and Biotechnology, Faculty of Life Sciences, University of Copenhagen, Copenhagen, Denmark<br />
2 Division of Food Chemistry, National Food Institute, Technical University of Denmark, Kongens Lyngby, Denmark<br />
E-mail: dasi@life.ku.dk<br />
The presence of vitamin D compounds has been established in a few plant species and could represent an<br />
alternative source of vitamin D. Interestingly, the metabolic pathway leading to the formation of vitamin D<br />
in plants is basically unknown. The enzyme Δ5,7-sterol-Δ7-reductase (7DHCR) is known to catalyze the<br />
conversion of 7DHC into cholesterol in vertebrates while in plants a similar enzyme (DWARF5) converts the<br />
Δ5,7-sitosterol (7DHS) into sitosterol. The structure similarity should make possible the conversion of 7DHS<br />
into vitamin D (vitamin D5) by exposure to UV B light.<br />
To verify if this conversion is occurring in plants A. thaliana dwarf5 mutants have been exposed to UV B<br />
light. This mutant is accumulating Δ5,7-sterols (mainly 7DHS) due to a mutation in the Δ7-reductase and it<br />
displays a dwarf phenotype due to the down regulation of the brassinosteroid biosynthesis.<br />
Moreover two cDNA sequences highly homologous to A. thaliana DWARF5 were isolated from S.<br />
lycopersicum. The activity of the codified enzymes was assessed by enzymatic assay via expression studies<br />
in yeast and plant. The results on yeast made by GC-MS sterol characterization of the transformants<br />
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