MANILA, OCTOBER 14, 2003  (STAR) By Arlene R. Obmerga  - Five Philippine crops–papaya, mango, banana, coconut, and corn– joined the biotechnology R&D bandwagon conducted by scientists from the University of the Philippines Los Baños (UPLB).

To make papaya tolerant to papaya ringspot virus (PRSV), which decreased the fruit’s production by 80 percent in 1995, scientists already obtained coat-protein (cp) resistance genes from the virus. Based on the project "Development of Transgenic Papaya Resistant to Ringspot Virus" monitored by the Philippine Council for Agriculture, Forestry and Natural Resources Research and Development-Department of Science and Technology (PCARRD-DOST), a team of researchers from UPLB’s Institute of Plant Breeding (IPB) led by Dr. Pablito Magdalita obtained the cp genes from PRSV itself, cloned those genes, and inserted them into the papaya embryos to protect the papaya from PRSV. The then embryos now grow into plants under observation at UPLB-IPB transgenic greenhouses.

Another group of UPLB-IPB researchers headed by Dr. Antonio Laurena is developing transgenic or genetically modified papaya with controlled ripening trait to prolong the fruit’s shelf life while retaining high quality in transit. Ripening genes from ‘solo’ papaya were cloned to produce the so-called delayed ripening gene. According to a report submitted to PCARRD-DOST, this gene inhibits the production of ethylene, which induces the ripening of papaya. The researchers are now observing the papaya in its fruiting stage at UPLB-IPB greenhouse.

On the other hand, genetic engineering in ‘carabao’ mango is under way. Another group of UPLB-IPB scientists headed by Dr. Evelyn Mae Tecson-Mendoza already developed somatic embryos in preparation for genetic engineering. The fruit’s shelf life.

For banana, genetic engineering, through the use of cp and other mutated viral genes for the development of resistant transgenic plants, is now being applied against banana bunchy top virus (BBTV). BBTV significantly reduces yield by 90 percent to 100 percent based on a report submitted to PCARRD-DOST. Thus, a team of UPLB-IPB researchers led by Dr. Olivia Damasco developed gene constructs by cloning the cp gene of local BBTV isolate.

In coconut, a group of researchers led by Dr. Rita Laude from UPLB’s Institute of Biological Sciences (IBS) aims to increase the medium chain fatty acid content of coconut oil to boost its use in high-value industrial applications. With a complementary deoxyribonucleic acid (cDNA) library constructed, the group screened out the full-length sequence of each gene and identified the genes that will lead to medium chain fatty acid production. According to the researchers, cloning coconut genes can increase fatty acid.

However, the researchers are yet to determine the specific percentage increase of fatty acid when cloning the genes. The UPLB-IBS team already identified six genes responsible for increasing the fatty acid in coconut. This may lead to better chances of developing a transgenic line of coconut producing more fatty acid with higher quality for industrial applications.

The project on corn, on the other, aimed at increasing its productivity through the development of molecular marker technology that would improve corn cultivars with high-yield potential combined with multiple disease resistance. The researchers believe that it is now possible to search for new and more effective genes to increase yield and resistance to diseases such as downy mildew and stalk rot by using the said technology. The reseachers already mapped the specific location in the chromosome where resistance genes can be found to protect the plant from downy mildew.

Some genes, which are possibly resistant to stalk rot and at the same time can lead to high yield have also been developed through crossing disease-susceptible line and disease-resistant line.

With the abovementioned developments in crop biotechnology, Filipino scientists hope to address food shortage in the country.

Reported by: Sol Jose Vanzi

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