1. Production of Anti Bacterial Proteins of Non-Plant Origin Lytic Peptides from Insects Lysozymes Other antibacterial Peptides 2. Inhibition of Bacterial Pathogenicity or Virulence Factors Inhibition of Bacterial toxins Other Approached 3. Enhancement of Natural Plant Defenses Enhanced Production of Elicitors Expression of cloned resistant genes Enhanced production of reactive oxygen species Expression of plant defense genes 4. Artificially Induced Programmed Cell Death at the site of infection R and avr genes Barnase and Barstar genes Bacterio-opsin gene Production of anti-Bacterial Proteins of Non-Plant Origin: a) Lytic Peptides from Insects: Small Proteins with alpha helices Causes pores in bacteriaExample: Cecropins, attacins – giant silk moth Cecropins Synthetic analogs of cecropin gene – Potato, Tobacco. Transgenic tobacco – bacterial wilt – delayed mortality. Limitation: Degradation of cecropins by plant proteases. b) Lysozyme Lysozymes are ubiquitous enzymes. Hydrolytic bacterial cell wall containing peptidoglycan. Examples Transgenic tobacco- hen egg lysozyme – resistance to several species. Transgenic potato – T4 Bacteriophage – Partial resistance to Erwinia. Transgenic tobacco- human lysozyme – Partial resistance to P.syringae. c) Other antibacterial peptides Lactoferin: Iron binding glycoprotein Bactericidal properties Transgenic Tobacco Human Lactoferin gene Delayed symptoms on Rhizoctonia solanaceae Trachyplesin: Codes for lytic peptides Horseshoe crab. Transgenic potato: genes from horseshoe crab - partial resistance. Limitation: Expressed reduced amount of tuber. Inhibition of Bacterial Pathogenicity or Virulence Factors a) Inhibition of bacterial toxins Pathogen protects itself against toxin by expressing tabtoxin resistant genes (ttr), transgenic tobacco with genes show resistance towards many bacteria. b) Other Approaches 3. Enhancement of Natural Plant Defenses a) Enhanced Production of Elicitors b) Expression of cloned resistant genes c) Enhanced production of reactive oxygen species A glucose oxidase gene from A.niger is cloned into potato plants resulted in resistance. This enzyme induce large amount of hydrogen peroxide. transgenic potato results in increased level of resistance. d) Expression of plant defense genes In certain cases resistance was not seen though high level of thionin is produced. This may be due to thionin is secreted into intracellular space, where bacteria are generally found. Plant defense mechanism is due to battery of synergetic reactions. Hence the expression of combination of heterologous genes would be more promising 4. Artificially Induced Programmed Cell Death at the site of infection R and avr genes applied to fungus Barnase and Barstar genes Barnase - Bacterial ribonuclease gene Barstar - Inhibitor of barnase Bacterial opsin gene Limitations Efficacy, durability, absence of toxicity and low environmental impact Gene silencing Got something to say about this post? Leave a comment...your comments are valuable for improving the posts.