plant biotic and abiotic stress

plant molecular mechanism to drought and salt stress, and other stresses.

1. PLANT BIOTECHNOLOGY BIOTIC & ABIOTIC STRESS Guided By Dr. Kishor Kumar Presented By Dushyant Kumar

2. Plant homeostasis Metabolic processes can only take place in specific physical and chemical environmental conditions. The maintenance of a steady state results in a meta-stable condition called homeostasis.

3. STRESS Modulation of homeostasis (Or) External factors that adversely affect the growth, development and productivity . Stresses trigger a wide range of plant responses: altered gene expression cellular metabolism changes in growth rates and crop yields

4. Abiotic Stress Water Excess- plant cell swell and burst. Drought- plant drying called desiccation. Temperature High- plant cell proteins denaturation, enzymatic activity imbalance. Low- chilling stress : affect the rate & amount of water & nutrient uptake Salts/ Ions Toxicity Deficiency Air pollution Radiation

5. 1. Signaling during excess salt

6. 2. Cold & Drought stress

7. PYL- pyrabactin resistance family molecule: acceptor of ABA PP2C- protein phosphatase 2 SnRK2- serine threonine like kinases family SLAC 1- slow anion channels NF Y- nuclear factor Y

8. Genes involved in responses

9. Proteins and hormones in response to stress

10. Biotic stresses Damages caused by living organisms like Weeds- compete with plant for food, water, minerals & space. Pathogens- causes diseases to plants Bacterial pathogens Fungal pathogens Viral pathogens Insects- cause damage to leaves, stem, fruit, root Herbivores animals

11. Pathogen Strategies Necrotrophic – plant tissue killed and then colonized; broad host range Bacteria and fungus 2. Biotrophic – plant cells remain alive narrow host range (1 plant species) viruses , fungus

12. Plant Defense Physical barriers: cuticle thorns cell walls 2. Constitutively produced chemicals phytoalexins proteins (e.g., Ricin) 3. Induced responses (the Plant Defense Response )

13. Induced responses Plant reaction to invading pathogens- role of hypersensitive reaction. Hypersensitive reaction initiates many changes in plant physiology and biochemistry. Early activation of defense related genes to synthesis pathogenesis related proteins Protease inhibitors to stop cell wall lysis by specific enzymes expressed by pathogens. Bacterial cell wall lytic enzymes ( chitinase , glucanase ). Change cell wall composition. Express enzymes providing structural support to cell walls via synthesis of lignin, suberin , callose , glycoproteins. Syntheises secondary metabolites to isolate and limit the pathogen spread. E.g.. – iso -flavonoids, phytoatexins

14. Thank you