This document discusses various applications of plant genetic engineering for crop improvement, including conferring insect resistance, resistance to abiotic stresses like drought and salinity, herbicide resistance, and improving crop quality and storage. It outlines specific genes used from bacteria, plants, and animals to generate these traits in transgenic crops. Common insect resistance genes discussed include Bt genes from Bacillus thuringiensis effective against lepidopteran and coleopteran pests. Abiotic stress resistance has utilized genes for osmoprotectants like proline, glycine betaine, and mannitol. Herbicide resistance relies on overexpression of herbicide targets or detoxification genes. Quality improvements include storage proteins and phytase genes.

1. Applications of Plant Genetic
engineering in Crop
Improvement
By
Mr. Pramod Vilas Shelar

2. Insect Resistance
• Approximately 40 Genes are used in conferring insect resistance in
crop plants.
• Most popular genes used from microbes in insect resistance are
 Bt gene from Bacillus thuringiensis.
Ipt Gene isopentyl transferase from Bacillus thuringiensis.
Cholesterol oxidase gene from Streptomyces.
Pht gene from Photorhabdus luminescens.
• Resistance inducing genes from higher plants can be
a) Proteinase and amylase inhibitor
b) Lectin- snowdrops lectin (GNA)
• Resistance gene From animals can be
a) Serine proteinase inhibitor

3. Resistance genes from microorganisms
• Bt Toxin gene
• Delta endotoxine : works against Lepidopteran larvae but some are
specific to Dipterian and Colepteran insect.
• Protein with approximately 1155 amino acids
• More than 100 cry protein sequences have been published
• Cry1Ab against European corn borer
• Cry1Ac against tobacco budworm and cotton ball worm
• Provids resistance against many plant pathogens.

4. • Cholestrol Oxidase(CO):Gene from
Streptomyces shows acute toxicity
to boll weevil larvae in tobacco.
• Isopentenyl Transferase: a gene
from Bacillus thuringiensis, codes
key enzymes in Cytokinin
biosynthesis pathway. Expression
in tobacco and tomato has resulted
in decrease in consumption.
Resistance genes from microorganisms

5. Resistance genes from higher plants
• Non Bt insecticidal gene which produces proteins which interfere with
nutritional needs of insect.
• Proteinase inhibitor: known since 1938 that plants contains peptides
acting as protease inhibitor, different proteinase are serine, cysteine,
Aspartate and metallo proteinases.
• Alfa Amylase inhibitor: Gene for amylase inhibitor is isolated from
Phaseolus Vulgaris , enzyme works against Zabrotes, Callosobruchus
inhibits gut amylase
• Lectins :Glycoproteins from plants, affects Aphids, and many other
sucking and Piercing insects. Works only when ingested in large
quantities
• Reduces Fecundity

6. Advantages of insect resistant Transgenic plants
• More effective
• Greater Resilience to weather
• Protection through out season
• Only pest eating crops are affected
• Insects are always treated at sensitive stage
• Can protect specific tissue
• No skilled labour required
• Biodegradable
• No risk to farmers
• No chemical residues in food and food products

7. Resistance to Abiotic Stresses
• Aboitic stresses like Drought , high temperature, low temperature, salinity
and alkanity adversely influence growth and induces senecense.
• Osmoprotectant lowers the osmatic potential
• Common osmoprotectant: Inorganics ions, polyols, soluble carbohydrates,
amino acids, Quaternary ammonium compounds such as glycine betaine.
• Several enzymes coding enzymes for biosynthesis of these osmoprotectants
have been cloned.

8. • Strong stress resistance has been reported with proline accumulation,
Gama Pyrroline-5 Carboxylate synthase is the limiting enzyme for
synthesis of proline
Glycine betain is wide spread in angiosperms, give drought and salt
stress resistance. Genes like CMO and BADH
Choline Betaine aldehyde Glycine betaine
• E.coli bacterial gene mt1D (mannitol1-1 Phosphate dehydrogenase)
biosynthesis of mannitol
Increases salt resistance
Resistance to Abiotic Stresses
CMO BAHD

9. • Fructane biosynthesis
• LEAs(late embryogenesis abundant) HVA-1 in barley for rice
• HSPs and AtHSF
• Fatty acid desaturase for Cold tolerance
Resistance to Abiotic Stresses

10. Herbicide Resistance
• Herbicide resistance plants form about 72% of total transgenic crops.
• Broad spectrum or nonselective and selective herbicide resistance are
used
• Approaches used for Herbicide resistance
1. Over expression of herbicide sensitive biochemical target
Example: Enolpyruvyl shikimate phosphate synthetase (EPSPS),
Acetolactate synthetase (ALS)
2. Structural alteration of target molecule
3. Detoxification of degradation of the herbicide

11. Herbicide Resistance

12. Transgenics for quality
• Transgenic for Storage protein
• 2s albumin protein gene from brazil nut expressed in tobacco by
Phaseolin promoter,
• Sunflower albumin protein was not allergic, was expressed in lupin using
pea vicilin gene promoter
• Amala gene from Amaranthus in potato
• Soybean gene in rice ,beta-casein gene in tobacco
• Phytase gene from alfa alfa to tobacco, hydrolyses phytate to inorganic
phosphate

13. Transgenics for Improved storage
• Flavr savr tomato in 1994
• Two approaches used
Antisense tech
1- aminocyclopropane-1- carboxylic acid deaminase

14. Antisense Tech.

15. ACC Deaminase

16. The End