BT-COTTON: SAFETY ASSESSMENT AND RISK MANAGEMENT

Transcription

1 BT-COTTON: SAFETY ASSESSMENT AND RISK MANAGEMENT T. M. MANJUNATH WORKSHOP ON GM CROPS WITH A FOCUS ON POST-RELEASE MONITORING Organised by: Department of Agriculture & Cooperation, Ministry of Agriculture, Government of India University of Agricultural Sciences, Bangalore and Biotech Consortium India Limited, New Delhi At UAS, Bangalore 09 January 07

2 WHAT IS BT-COTTON? Bt-cotton contains Lepidopteran specific gene(s) derived from the soil bacterium, Bacillus thuringiensis introduced into it by genetic engineering

3 Transgenic Technology: What is Unique? A transgenic plant carries new gene(s) New gene(s) can be Introduced into a plant from any source -bacteria, virus, fungi, animals - thus overcoming taxonomic or reproductive barrier A Big Breakthrough! Man-made! Unnatural. Hence its safety is doubted?

4 1996: A Turning Point Three Bt-crops approved in USA Bt-corn against European Corn Borer Bt-potato against Colorado Potato Beetle Bt-cotton against Cotton Bollworms

5 Bt-Corn Against European Corn Borer Bt-Potato Against Colorado Potato Beetle

6 Bt-Cotton Against Bollworm Complex Cotton Bollworm Tobacco Budworm Pink Bollworm

7 DEVELOPMENT OF BT-CROPS IN USA 1983 : First transgenic plant in lab 1990 : First Bt plants 1992 : Lead lines selected. First field Tests 1993 : Seed companies cross into elite germplasm 1995 : Safety studies completed 1996 : USDA & FDA consultation completed EPA approval for commercialization ~ 14 years of intensive research and field trials. Millions of $ investment

8 DEVELOPMENT OF BT-COTTON IN INDIA 1994: Application to DBT by MAHYCO for import of Bt-cotton seeds from Monsanto,USA 1995: Permit to import seeds (100 gm Coker 312) 1996: Seeds imported. Greenhouse studies. Back-crossing : Limited field trials. Feeding and allerginicity studies : Multi-location field trials : ICAR trials and other multi-location trials More bio-safety studies 26 Mar 02: GEAC approval for commercialization >500 agronomic field trials and bio-safety studies for 7-8 years. Faced unjustified opposition.

9 26 MARCH 2002 Govt. of India approved Mahyco s Bt-Cotton Containing Bollgard Bt gene, cry 1Ac,, licensed from Monsanto targeted against cotton bollworms India s First Biotech Crop

10 WHAT IT TOOK TO GET APPROVAL? Comprehensive research data to demonstrate: Bio-safety Environmental safety Social and economic benefits Safety is accorded the highest priority in biotechnology

11 Safety Assessment

12 SAFETY ACCORDED HIGHEST PRIORITY Throughout Discovery, Product Development and Advancement Post-Market Market Field Production Variety Development Commercialization Advancement Line Selection GH & Field Evaluation Transformation Development Gene Discovery Product Concept Discovery

13 SAFETY ASSESSMENT Takes place at two Levels: Internal Safety Audit by Product Developers - Internal experts Safety Regulations by Government - National safety regulations - International safety guidelines (Cartagena,, FAO, WHO)

14 WHAT ARE SAFETY CONCERNS? v v v v v v Toxicity Allergenicity Out-crossing / Gene flow Effects on non-target organisms Environmental impact Pest resistance All safety issues are to be addressed before regulatory approval is given for any product

15 ISSUE: SAFETY TO NON-TARGET ORGANISMS Apprehension: Bt-protein may have toxic effect on humans, animals or other non-target organisms

16 WHAT IS BACILLUS THURINGIENSIS (BT) Soil bacterium; ubiquitous First discovered in 1901 in Japan About 80 subspecies /strains Different strains produce their own insecticide proteins >140 Bt-insecticide cry proteins characterized Endospore Crystal EM view of Bt with spores and crystals Each cry protein selectively affects insects belonging to a particular order (eg( eg.. Lepidoptera, Coleoptera, Diptera etc) and at their very early larval stage EM view of a purified inclusion body

17 BT-GENES USED IN COMMERCIALIZED TRANSGENIC CROPS Cotton - Cry1Ac, Cry2Ab, Cry1Ab Corn - Cry1Ab, Cry1Ac, Cry 3Bb Potato - Cry3Ab Selected after thorough screening to ensure that the Cry proteins have no toxic or allergenic effects on higher animals

18 SELECTIVE ACTION OF BT IN INSECTS Ingestion (While feeding plant tissues) Solubilization (Alkalinity) Activation (ph >9.5) Binding (Specific receptor) Insertion (Damage gut wall) Pore formation Cell lyses D e a t h

19 BT HAS NO IMPACT IN HIGHER ANIMALS BECAUSE OF.. Acidic intestine Very low ph (~1.5 in humans) Absence of required receptors

20 SAFETY TO NON-TARGET ORGANISMS Feed safety studies were conducted using high dose of Bt-cotton seed-meal / protein on: Fish Birds Mammals - goats, buffaloes, cows, rabbits Honey bees Earthworms Biological control agents (Lacewing, Ladybird beetles etc) RESULTS REVEALED NO ILL EFFECTS & BT TO BE SAFE

21 FEED-SAFETY STUDIES CONDUCTED AT Industrial Toxicological Research Centre, Lucknow National Dairy Research Institute, Karnal Central Institute of Fisheries Education, Mumbai Central Avian Research Institute, Izatnagar National Institute of Nutrition, Hyderabad G. B. Pant Univ of Agri. and Tech., Pantnagar

22 ISSUE: SUBSTANTIAL EQUIVALENCY Apprehension: The introduction of the new Cry gene may alter the chemical composition and characteristics of the plant, thereby adversely effecting other organisms

23 COMPOSITIONAL EQUIVALENCY: PROXIMATE ANALYSES g / 100 g Protein Fat Carbohydrates Ash Moisture Control Bollgard 531 Bollgard (Event 531) is substantially equivalent to conventional cotton

24 COMPOSITIONAL EQUIVALENCY: TOXICANTS Gossypol, % dry weight Dihydrosterculic acid, % total lipids Sterculic acid, % total lipids Malvalic acid, % total lipids Control Bollgard Forage composition of Bollgard cotton is substantially equivalent to conventional cotton - Similar results found with Roundup Ready Cotton Event 1445

25 MOUSE ORAL TOXICITY STUDIES WITH CRY1AC 35 Mean body Weight, gm Body wt., pre-test Males Body wt., day 7 males Body wt., pre-test Females Body wt., day 7 females Vehicle control 500 mg/kg Cry1Ac 1000 mg/kg Cry1Ac 4300 mg/kg Cry1Ac No acute toxic effect on health upon ingestion of large amounts based on body weights, food consumption and gross necropsy About 14 other oral toxicity studies were conducted on rats, rabbits, r sheep etc.

26 Issue: Cry Proteins in Soil Apprehension: Bt-protein may accumulate in soil when roots and other parts of Bt-plants are incorporated in soil and this may have harmful effect on soil organisms.

27 BT PROTEINS IN SOIL GET DEGRADED No difference between soils from Bt-crop and non-bt Bt-crops. Readily susceptible to metabolic, microbial and abiotic degradation once they are ingested or excreted into soil Bt insecticidal proteins cannot bio- accumulate causing delayed effects

28 Issue: Gene Flow & Weediness Apprehensions: Genes may escape from transgenic plants and cause Genetic contamination or Genetic pollution. Vertical gene transfer: : Pollen containing Bt genes from Bt -crop plants may be transferred to their relative plant species, including weeds, making them insect resistant ( Super( weeds ) Horizontal gene transfer: : Genes from transgenic plants may be transferred to bacteria and other microorganisms or from bacteria to plants, thereby affecting their original constitution

29 Gossypium spp.(cotton) New World Cotton - Tetraploid Gossypium hirsutum Gossypium barbadense Desi Cotton - Diploid Gossypium arboreum Gossypium herbaceum No cross pollination between tetraploid and diploid species because of reproductive incompatibility

30 GENE FLOW IS A NEGLIGIBLE RISK Vertical gene transfer: Feral crops related to corn, potato and cotton cannot be pollinated by these crops due to: Difference in phenology (Diff. in flowering time etc.) Sexual incompatibility (Diff. in chromosome umbers) Difference in habitat Horizontal gene flow: Several sub-species species of Bt already exist in soil. Bt crops are not going to add anything more to the already existing flux of cry genes among soil microorganisms No evidence of horizontal gene transfer from plants to microbes

31 WEED RELATIVES OF COTTON (GOSSYPIUM) Gossypium stocksii : Occurs in northern part of Gujarat (India) where cotton is not cultivated. Bollworms do not feed on this weed. Gossypium tomentosum : Occurs in Hawaii (USA) where this weed is considered on the decline. However, Bt-cotton is not cultivated in Hawaii.

32 ISSUE: PEST RESISTANCE Apprehension: The insect pests constantly exposed to Bt proteins may develop resistance thereby resulting in super pests.

33 INSECT RESISTANCE MANAGEMENT (IRM) STRATEGIES Proactive IRM strategies have been initiated to prevent or delay the potential development of resistance by the target pests

34 IRM STRATEGIES WITH BT CROPS Optimal dose Refuge Gene stacking Baseline susceptibility data for target pests Surveillance for product performance Bt-crop as a major component of IPM

35 REFUGE FOR INSECT RESISTANCE MANAGEMENT

36 REFUGE A refuge is a crop without Bt gene planted close to that with Bt gene Insect will feed and proliferate on non-bt plants and will remain susceptible to Bt protein. When these mate with the scant few that have become resistant by surviving on the Bt crop, the susceptible genes will dilute any resistant genes in the overall gene pool.

37 Refuge Structured 20% with normal pp measures 5% with no control Natural Highly preferred alternative hosts

38 Refugia - Before Selection refuge Bollgard cotton R R S S

39 Refugia - During Selection refuge Bollgard cotton R R S

40 Refugia - After Selection refuge Bollgard cotton R S R S R + S = RS / SS (No RR = Resistant population)

41 Refugia - Before Selection refuge Bollgard cotton R R S S

42 NATURAL REFUGIA

43 Helicoverpa armigera feeding on Red Gram (Tur)

44 Helicoverpa armigera feeding on Bengal Gram

45 Helicoverpa armigera feeding on Sunflower

46 Relative Population of Helicoverpa armigera larvae on alternate crops and cotton Ratio Cotton Pigeonpea Sunflower Chickpea Sorghum Crops Fig 5b Larval ratio (Cotton v/s other hosts) at Eklashpur Ratio Cotton Pigeonpea Sunflower Sorghum Crops Fig 5b Larval ratio (Cotton v/s other crops) at Hosur

47 GENE STACKING (PYRAMIDING) Two Bt genes eg. Cry1Ac & Cry2Ab in the same plant with different modes of action. Bt gene with other insecticidal gene eg.. Protease inhibitor, amylase inhibitor. In case an insect develops resistance to one gene, it would succumb to the other

48 NO INCIDENCE OF PEST RESISTANCE In the last 10 years ( ) of commercial cultivation of Bt-cotton and other Bt-crops on millions of acres, there has not been any field incidence of pest resistance to in planta expressed Bt-proteins Lab studies and incidence of resistance by other insects to Bt sprays have often been misquoted as resistance to Bt-crops

49 ISSUE: REGULATION OF GM CROPS Apprehension: Regulation of genetically modified crops is not adequate and dependable

50 REGULATION OF GMOs IN INDIA Ministry of Science & Technology Ministry of Environment & Forests DBT GEAC IBSC RCGM Each major committee has sub-committees, comprising experts in various fields drawn from various public institutions

51 SAFETY REGULATIONS IN USA Three federal agencies ensure safety of biotech products: USDA: EPA: Field testing and environmental safety Environmental, food and feed safety for pest-protected protected product registration and sales; and for herbicide use on Roundup Ready crops FDA: Food and feed safety Similar regulatory bodies exist in other countries also

52 Are the Criticism/Opposition Justified? The following facts reveal a lot

53 SAFETY OF GMOS: A NEVER-ENDING ENDING DEBATE! Issues raised have been mostly speculative, complex, inconsistent and confusing. The issues ranged from: Ethical - Emotional Economical - Egoistic Political - Publicity Ignorance - Arrogance Legal - Illegal Social - Scientific Scientific issues should receive utmost priority

54 SAFE HISTORY OF BACILLUS THURINGIENSIS (BT) In 1901 : Bt discovered in Japan Since 1956 : Used as foliar spray to control a variety of pests all over world Since 1996 : After due regulatory approval as safe and beneficial, transgenic Bt-crops commercially grown on several millions of hectares in several countries In 2001 : Bt completed 100 years No negative impact for more than 100 years!

55 GLOBAL AREA OF TRANSGENIC CROPS, Hectares in Million More than a 50-fold increase in 10 years

56 GM-COTTON: COUNTRIES & AREA IN Countries, 9.8 M Ha (Year of Introduction in Parentheses) USA 4.6 M Ha (1996) China 3.3 M Ha (1997) Mexico 0.12 M Ha (1998) Colombia < 0.1 M Ha (2002) Australia 0.3 M Ha (1996) Argentina 0.07 M Ha South Africa 0.03 M Ha India 1.3 M Ha (1997) (1998) (2002)

57 AREA UNDER BT-COTTON IN INDIA (IN 6 to 9 STATES) Year Area in Hectares Area in Acres ,415 72, ,240 2,13,099 No. of Bt farmers 25,000 75, ,53,000 13,66,463 3,50, ,66,690* 31,28,724 10,00,000 *This adoption is about 14% of 9.0 m ha of total cotton area in India

58 IMPACT OF BT COTTON IN INDIA, 2004 State Bollworm pesticide reduction % Rs/acre Yield increase % Qtl/acre Increase in net profit % Rs./acre Andhra Pradesh 79 2, ,782 Karnataka Maharashtra ,270 Gujarat ,545 15,095 Madhya Pradesh 60 1, ,270 Tamil Nadu ,263 All India av. 72% 1,137 58% % 5,950 Indian Market Research Bureau (IMRB), April 05

59 HIGHEST SAFETY STANDARDS EVER Never before in the history of agriculture has food been subjected to such stringent safety assessment as biotech products Healthy criticism is always helpful. Blind opposition is unhealthy Safety is our primary responsibility. We should always strive to do better

60 Incorrect knowledge is more dangerous than ignorance!

61 Effective dissemination of correct knowledge is a pre-requisite requisite to promote any new technology Biotechnology has the potential to revolutionize agriculture and benefit the farmers and society

62 Thanks T. M. Manjunath