Biomedical Engineering Reference
In-Depth Information
and this technology has been transferred to farmer's level. However, the effective-
ness of this technique is limited by the presence of residual and alternative sources
of inoculum in abaca plantations, making the absolute eradication of the virus
diseases almost impossible. Often, the initially disease-free planting materials
will get infected within a few growing seasons. It is therefore of great importance
that new abaca cultivars which are resistant to pests and diseases be developed.
Genetic engineering utilizing plant transformation and gene cloning are becom-
ing important tools in plant improvement. However, the success in utilizing the
potentials of the technique is largely dependent on the development of efficient and
reproducible protocols for the establishment of cell suspension cultures, induction
of somatic embryogenesis, and protoplast fusion.
Excellent progress has recently been made in obtaining regenerants from
somatic embryoids and recently gene expression in abaca. The technique involves
adventitious shoot induction, shoot multiplication in the medium supplemented
with BA or 2,4D and coconut water. Addition of 2,4D also induced callus forma-
tion. Subsequent root induction in adventitious shoots was also obtained in MS
medium supplemented with IAA, NAA, and IBA [
48
]. Buds and shoots were
induced in young floral sections and floral apices in MS medium supplemented
with Ki in combination with NAA, IAA, or IBA. The formation of embryogenic
(nodular) structures which developed into shoots was first observed in explants
grown in MS medium supplemented with 2-ip and Ki. Somatic embryos have been
included from cell suspension cultures derived from globules that formed from
meristematic buds (scalps) or leaf sheaths in modified liquid MS medium
supplemented with 2,4D, zeatin, and
L
-cysteine. These methods of producing
somatic embryos are essential to the process of genetically engineering abaca.
Transient expression of the GUS reporter gene has been observed in transformed
meristematic globules of abaca [
49
]. Researchers at the FIDA and the University of
the Philippines Diliman (UPD) and Los Ba
˜
os (UPLB) campuses are collaborating
to genetically engineer abaca bunchy top-resistant and abaca mosaic-resistant
abaca.
Opportunities/Prospects and Developments
The Philippine abaca industry is expected to continue making a stronghold in both
the domestic and international markets. The growing concern for environmental
protection and forest conservation worldwide has further provided demand oppor-
tunities to natural raw materials like abaca. Considering its superior fiber qualities
over other natural materials, the utilization of abaca for industrial applications is
expected to increase.
The total world abaca demand averaged 73,917 MT per year, 85 % of which was
supplied by the Philippines. The Food and Agriculture Organization (FAO) of the
United Nations projects that global consumption of abaca will increase further to
more than 85,000 MT.
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