BUKU ABSTRAK - Universiti Putra Malaysia

Oil Palm Metallothionein-like Gene (MT3-B) Promoter as an Inducible Promoter
for Root-specific Expression
Assoc. Prof. Datin Dr. Siti Nor Akmar Abdullah
Zubaidah Ramli
Institute of Tropical Agriculture, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 4117; sakmar@agri.upm.edu.my
Keywords: Elaeis guineensis, metallothioneins, promoter analysis, Zn2+ binding
Somatic Embryogenesis from Scutellar Embryo of Oryza sativa L. Var. MR219
Assoc. Prof. Datin Dr. Siti Nor Akmar Abdullah
Syaiful Bahri Panjaitan, Maheran Abdul Aziz, Sariah Meon and Othman Omar
Institute of Tropical Agriculture, University Putra Malaysia,
43400 UPM Serdang, Selangor, Malaysia.
+603-8946 4117; sakmar@agri.upm.edu.my
1
Agriculture
Silico analysis showed that type 3 oil palm metallothionein-like gene MT3-B contain important putative
promoter regulatory elements. The identified motifs include root-specific element, metal-responsive element,
W-boxes, GCC-box, TATCCA element, binding element for cytokinin response regulators and pollen-specific
elements. Promoter activity of the MT3-B gene was analysed using a transient assay by bombarding oil palm
tissue slices with a ?-glucuronidase (GUS) gene construct and a stable reporter assay by analysing GUS expression
in transformed Arabidopsis thaliana plants. Transient expression analysis revealed MT3-B promoter activity in
oil palm root tissues but not in fruit mesocarp at 12 weeks after anthesis and spear leaves. The T3 homozygous
transgenic Arabidopsis plants, harbouring the MT3-B promoter/GUS construct, showed reporter activity in
cotyledons and mature leaves with lower expression levels in root tissues. The expression levels in the roots of
the T3 homozygous transgenic plants increased five and 2.5-folds when treated with 80? M of Zn2+ and Fe2+
respectively. Altogether, these results indicate that the MT3-A and MT3-B promoter activities may be regulated
by a variety of abiotic factors and MT3-B promoter may potentially be manipulated to be used in plant genetic
engineering for induced synthesis of gene product.
Somatic embryogenesis is an efficient plant regeneration system and it is a potentially useful tool for genetic
transformation. An experiment was carried out on somatic embryogenesis from scutellar embryo of rice var.
MR219. High intensity of callus formation (100%) was initiated through culturing the scutellar embryo on
modified MS medium with the macro nutrients reduced to half-strength and supplemented with different 2,4-
D concentrations (1, 2, 4 and 6 mgL-1). Meanwhile the highest percentage of embryogenic callus formation
(80%) was obtained on modified MS medium containing 4 mgL-1 2,4-D. The calli produced were yellowish and
friable with nodular structures on the surface. Rounded cells with highly dense cytoplasm were observed under
an inverted microscope and their viability confirmed based on apple green fluorescence staining in FDA solution.
High mean number of somatic embryos was also produced in this treatment at 85 somatic embryos per explant.
Upon transferring the somatic embryos onto modified MS medium with 2 mgL-1 BAP and 0.05 mgL-1 NAA for
germination, 82.5% of the somatic embryos germinated into seedlings.
Keywords: Rice (Oryza sativa L.) var. MR219, 2,4-dichlorophenoxyacetic acid phthalenacetic acid, 6-Benzylaminopurine