The Republic of the Philippines

8/11/2019 The Republic of the Philippines

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I. INTRODUCTION

GM or biotech crops were initially grown in 1991 in China (tobacco) and then in theUS in 1997 (soybean, cotton, and corn) at 1.7 ha.

In 2004, there are ~50 GM crops approved in commercialization that are utilized forhuman food and animal feed.

II. OBJECTIVES

At the end of this lesson, the student should be able to gain an appreciation andunderstanding of genetically modified (GM) corn, cotton, and papaya.

III. CONTENT

A. GENETICALLY MODIFIED (GM) CORN

Maize line MON 810 (trade name YieldGard) was developed through a specificmodification to be resistant to attack by European corn borer (ECB, Ostrinia nubilalis).Cry1Ab, derived from Bacillus thuringiensis. Delta-endotoxins, such as the Cry1Abproteins, only insecticidal only to lepidopteran insects (ECB).

The Method of Genetic Modification for MON8 10

Maize line MON 810 was produced by biolistic transformation of maize genotype Hi-IIwith a mixture of plasmid DNAs, PV-ZMBK 07 and PV-ZMGT 10 . The PV-ZMBK07 plasmidcontained the cry1Ab gene and PV-ZMGT 10 plasmid contained the Cp4 EPSPS and goxgenes. Both plasmids contained the nptII gene under the control of a bacterialpromoter.

Characteristics of GM Corn MON8 10

The introduced DNA

MON810 genomic DNA cry1ab gene and enhanced CaMV 35S (E35s) (use in planttransformation )

Glyphosate tolerance(weeds resistance) (CP4 EPSPS and gox gene)

Genetic Stability of the Introduced Trait
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MON810 was derived from the 3 rd generation of backcrossing and stableintegration

Backcrossing is a crossing of a hybrid with one of its parents or an individualgenetically similar to its parent, in order to achieve offspring with a genetic

identity which is closer to that of the parent.

Expressed Material

The synthetic cry1Ab gene was linked to a strong constitutive promoter andmodified for maximum expression in corn. The cry1Ab protein was shown to degradereadily in the environment.

Environmental Safety Conditions

Outcrossing

Since pollen production and viability were unchanged by the genetic modificationresulting in MON810, pollen dispersal by wind and outcropping frequency should be nodifferent than for other maize varieties. Gene exchange between MON810 maiz and theother cultivated maize varities will be similar to that which occur naturally betweencultivated maiz varieties at the present time.

Maize (Zea mays ssp. Mays) freely hybridizes with annual teosinte (Zea mays ssp.Mexicana) when in close proximity.

Weediness Potential

Cultivated maize is unlikely to establish in non-cropped habitats and there have been noreports of maize surviving as a weed.

Secondary and Non-Target Adverse Effects

The history of use and literature suggest that the bacterial Bt protein is not toxic tohumans, other vertebrates, and beneficial insects. In summary, it was determined thatwhen compared with currently commercialized maize varities, MON810 maize did not

present an increased risk to or negative impact on interacting organisms, includinghumans, with the exception of specific lepidopteran insect species.

Impact on Biodiversity

MON810 has no novel phenotypic characteristics that would extend its use beyond thecurrent geographid range of maize production. Since the risk of outcrossing with wild
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relatives in North America is remote, it was determined that risk of transferring genetictraits from MON810 maize to species in unmanaged environments was insignificant.

Other Considerations

In order to prolong the effectiveness of plant-expressed BT toxins, and the microbialspray formulations of these same toxins, regulatory authorities in Canada and UnitedStates have required developers to implement specific Insect Resistance Management(IRM) Programs.

Food and/or Feed Safety Considerations

Dietary Exposure

Maize is a raw material for the manufacture of starch. As such, dietary exposure tohumans of grain from insect resistant hybrids will not be different from that for othercommercially available field maize varieties.

Nutritional Data

The observed variations in nutritional composition were judge to arise from normalvariability rather than as a result of the inserted novel traits. As a percentage of dryweight, the component analyses for line MON810, are approximately: protein 13.1%; fat3.0%; moisture 12.4%; calories 408 Kcal/100g; ash 1.6%; and carbohydrates 82.4%.

Toxicity

The low potential for toxicity of plant-expressed Cry1Ab protein was furtherdemonstrated by a lack of amino acid sequence homology with known protein toxins,rapid digestion in simulated gastric juices, and lack of toxicity in feeding studies withlaboratory animals.

Allergenicity

The Cry1Ab protein was evaluated for potential allergenicity by examining: (1)physiochemical characteristics; (2) amino acid sequence homology to known protein

allergens; (3) digestibility; and (4) history of safe use of microbial insecticides containingthis protein.

The source of the cry1Ab gene has a long history of use on food crops as a biopesticideand no evidence of adverse effects. This fact, combined with the lack of amino acidsequence homology between Cry1Ab protein and known allergens, and the rapid


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degradation of Cry1Ab protein in acidic gastric fluids, were sufficient to provide areasonable certainty of lack of allergenic potential.

B. GENETICALLY MODIFIED (GM) PAPAYA

Papaya(Carica papaya L) best known member of Caricaceae, a small dicotyledousfamilyCarica largest genus with 23 speciesMating System dioiecious(staminate and pistillate plants) or gynodioecious(hermaphrodite and pistillate plants)

Papaya Transgenic Line 55-1 and 63-1

Developed using recombinant DNA to resist infection by Papaya ringspot virus (PRSV).

inserted with virus-derived sequences that encode PRSV coat protein (CP).PRSV potyvirus group

- ony infects papaya causing serious disease and economic loss

GM Papaya exh ibit pathogen -derived resistanceCross protection uncoating (removal of CP) from the incoming virus.

Method of Genetic Modification for GM Papaya

Produced by biolistic (particle bombardment) transformation

Characteristics of the GM Papaya

The introduced DNA

DNA from line 55-1 contained the PRSV CP gene with NPTII and GUS gene. Incompleteand under regulatory control of promoter.DNA from line 63-1 with PRSV CP and NPTII but no GUS gene. Result: not functional.

Field Testing

55-1 and 63-1 were field test in United States (1991 -1996)-laboratory,greenhouse and field-contained typical agronomic characteristics of the parent papaya Sunset withresistance to PRSV infection.


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-had no effect on nontarget organisms or the environment.

Weediness

-No Carica species considered a weed.-if PRSV-resistance transferred from line 55-1 or 63-1 to another Carica, the resultantoffspring would not be weed pests.

Secondary and Not-Target Adverse Effects

-its was concluded that it would not result in any deleterious effects or significantimpacts on nontarget organisms.- The PRSV coat protein can be ingested by animals,humans when it is consumed.

Nutritional Data

-rich in Vitamins A and C and total soluble solids (TSS)-TSS in PRSV-infested transgenic papaya are slightly higher than non-transgenic.-Vitamin A are the same.-Vitamin C are slightly lower in transgenic line 55-1 than to non-transgenic

Endegonous Toxicants

Benzyl isothiocyanate (BITC) in the latex of green papaya tissues has been linked toabortions in pregnant women and prostate cancer in Japanese men over the age of 70.

Toxicity and Allergenicity

-safe consumption-does not possess any physiochemical properties (proteins allergens or toxins)

IV. GENERALIZATION

V. REFERENCES


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