1. WELCOME

2. PLANT- PATHOGEN INTERACTION IN DISEASE DEVELOPMENT with reference to Pyricularia oryzae causing Rice Blast AKHILESH K KULMITRA I.D. NO – PAL(M) 4016 DEPARTMENT OF PLANT PATHOLOGY 69

3. ORGANISATION OF TOPIC Conclusion 68

4. Introduction Rice Facts • Rice is the staple food of almost half of the world's population • More than 90% of world’s rice is grown and consumed in Asia. • Among the rice producing countries, India rank 2nd after China. (FAO, 2014) 67

5. The Major Rice Growing Countries (204.3 Mmt) 1st -Production 2nd -Production 3rd (152.6 Mmt) (69.0 Mmt) SOURCE : FAOSTAT(October 2014) 66

6. Contribution of State in India's Rice Production 1st –Area & Production 2nd –Area & Production 1st -Productivity www.mapofindia.com 15th jan.2015 65

7. Factors Effecting Rice Plants BIOTIC STRESS ABIOTIC STRESS Extreme temperatures High winds Drought Flood Chilling/Freezing pH levels /Salinity high radiation Fungi Bacteria Viruses Nematodes 64

8. Worldwide distribution of Rice Blast disease blast disease reported countries www.intechopen.com 63

9. Distribution and occurrence of Rice Blast Disease in India Source: ICAR 62

10. Mandya District (All Taluk Affected by Blast Disease) 61

11. Yield losses • Each year, rice blast disease ( Magnaportheoryzae) claims between 10–35%of the global rice harvest, this is more than enough rice to feed 60 million people. This would have an enormous impact on global food security. • Khush and Jena (2009) • Eastern India has the highest occurrence of blast followed by North and South. yield losses reach as high as 50-100% in upland conditions. • Widawsky and O’Toole (1990) Repeated epidemics and frequent breakdown of rice blast resistance causing yield losses of 20–100% have been reported in India. Sharma et al., (2012) 60

12. Yield losses • Blast is known to attack all above ground parts as well as during all growth stages of plant. • Recent reports have shown that the fungus has the capacity to infect plant Roots also. (Sesma and Osbourn., 2004). 59

13. History • Rice blast was 1st reported in China by Soong Ying-shin in 1637. • In Japan by Tsuchiya in 1704. -Goto,1953 • In India: • 1st recorded in Thanjavur (Tanjore) delta of Tamil Nadu in 1971 BY Mc Rae (1922). • It attracted attention only when a devastating epidemic occurred in 1919. • -Padmanabham (1965) 58

14. Causal Organism • Pyricularia • Kingdom: Fungi • Division: Ascomycota • Subdivision: Pezizomycotina • Class: Sordariomycetes • Subclass: Sordariomycetidae • Order: Magnaporthales • Family: Magnaporthaceae • Genus: Pyricularia Sacc. 1880 • Species: ………………………...... • Scientific classification: 57

15. Species of Pyricularia 56

16. ① white point type: white, mostly round, does not produce spores. The young leaves in susceptible occurs. ④ brown-point type: the lesion is brown dots, more confined between the veins, brown necrotic central portion, the peripheral portion of the yellow poison, no spores. Symptoms • Large spindle shape lesions usually develop a greyish center, with a brown margin on older lesions. ② acute type: dark green spots, most nearly circular needle to the mung bean size, gradually developed into a spindle. ③ chronic type: Typical spindle-shaped, the outermost layer of yellow, brown inner ring, the central gray; spots at both ends extending outwardly brown necrotic cord. 55

17. Rice Blast : Symptoms Leaf Healthy leaf   Infected leaf Nodal  Neck Collar 54

18. HOST – PATHOGEN INTERACTION 53

19. Plant–Pathogen Interaction • Plant–pathogen interactions are the interactions taking place between a pathogen (e.g. fungi, bacteria, virus, nematodes etc.) and their host (e.g. humans, plants).  Pathogenicity Factor Source: Wikipedia Disease = Life cycle on host completed 52

20. INTERACTION Natural = No effect Beneficial Harmful = pathogenic Rice-Blast interaction Bio-fertilizer Bio-control 51

21. Rice Host R I C E B L A S T Rice Blast Pathogen 50 Pyriculariaoryzae

22. Rice: A Model Plants for Host-Pathogen Interaction Valent (1990). 49

23. In addition to its economic importance, Rice Blast provides a reliable model system to study Host- Pathogen Interactions • A well defined infection process. • Diversity of fungal populations. • Host cultivar/species specificity and pathogenecity. • Short sexual cycle. • The disease cycle is rapid. • Easily culture under laboratory condition. • Whole genome sequences of both rice and Magnaporthe grisea. • Magnaporthe grisea is phylogenetically closely related to other model filamentous fungi. The American Phytopathological Society (1990) 48

24. PATHOGEN Necrotrophic pathogen Ex - gray mold fungus Botrytis cinerea bacterial pathogen Erwiniacarotovora Biotrophic pathogen Ex: fungus Blumeriagraminis bacterial pathogen Xanthomonasoryzae Hemibiotrophic pathogen Ex-fungus  PLANT PATHOGENS An organism that, to complete a part or all of its life cycle, grows inside another organism and in so doing has a detrimental effect on its host. Magnaporthegrisea Kankanalaet al., (2007) 47

25. Mode of Infection Attachment • Pre Penetration phase : • Attachment of blast conidia • Germination of conidia • Hooking • Appressorium formation • Penetration and entry phase • 3. Post penetration phase: • Invasion and growth • Symptom expression • Sporulation Germination Hooking Appressorium Formation Penetration Invasion and Growth Lesion/Symptoms Sporulation 46

26. Life Cycle of Rice Blast Sexual Asexual 45

27. A B C D 44

28. The Penetration Process of Magnaporthe grisea 43

29. A E PP C O E B GT AP C D F AP AP PP 42

30. DEFENSE MECHANISMS IN PLANTS • Pre existing defence mechanism Physical/ structural barriers Biochemical • Wax • Cuticle • Cell wall • Natural openings • Inhibitors • Phenolic compounds 41

31. Cuticular waxes relieve self-inhibition of germinationand appressorium formation by the conidia ofMagnaporthe grisea HEGDE,Y AND KOLATTUKUDY,P.,(1997) 40

32. Induction of Magnaporthe oryzae conidia germination and appressorium formation by plant surface waxes Hegde,Y and Kolattukudy,P.,(1997) 39

33. Effects of Magnaporthe grisea conidial population density on germination and appressorium formation More no. of conidia less appressorium formation due to fatty acid toxicity. 38 Hegde,Y and Kolattukudy,P.,(1997)

34. Reversal of self-inhibition of germination and appressorium formation of Magnaporthe grisea conidia by Rice leaf surface wax Hegde,Y and Kolattukudy,P.,(1997) 37

35. Penetration of hard substrates by a fungus employing enormous turgor pressures RICHARD J. HOWARD et al.,(1991) 36

36. Materials and Methods • Organism- Magnaporthe grisea (strain 042) • When conidia placed on distilled water surface Conidia germinate in 1-3 hour. • Appressorium formation start in 4 hour. • Complete appressorium form in 6-8 hour. 34

37. substrates used for appressorium formation and penetration- Mylar [poly(ethylene terephthalate)] films (non-biodegradable), numbered 1-6. Vickers's indentation technique (load kept 2-20g Density gradient technique crystallinity Sample 1 was heated at various temperatures (T anneal) and for various times (T anneal) to yield samples 2, 3, 5, and 6. Sample 4 was obtained separately. ND, not determined. 33

38. The external osmotic pressure induce cytorrhisis (collapse) of Appressoria AP. Incubation period 1st -water droplet on mylar membrane (6-8 hr) then after 18,26, 46hr replaced with PEG-8000 • RICHARD J. HOWARD et al.,(1991) 32

39. 1-140MPa,2-173MPa,3-180MPa, 4-200MPa,5-240MPa,6-250MPa • RICHARD J. HOWARD et al.,(1991) 31

40. Result • The incubation time required for penetration was directly proportional to surface hardness. • The appressorium turger pressure was also direct related with the ability of penetration. 30

41. MPG1, a gene encoding a fungal Hydrophobins of Magaporthe grisea, involved in surface recognition BECKERMAN AND EBBOLE, (1996) 29

42. Hydrophobins (MPG1) Wostenet al., (1994) Rodlet layer helps in adhesion of hyphae to hydrophobic surfaces Hydrophobins MPG 1 Wet the surface of hyphae not produced appressorium Hydrophobins mutant mpg1 Beckerman and Ebbole(1996) 28

43. Effect of substrate on appressorium formation • Guy11 strain conidia formed appressorium on Teflon film and not on the hydrophilic side of Gelbond film. • No appressorium formation on glass coverslips. • Treatment of coverslips with 10% chromic acid or 50% hydrofluoric acid allowed appressoria formation. Beckerman and Ebbole,(1996) 27

44. (Beckerman and Ebbole, 1996) 26

45. Beckerman and Ebbole (1996) 25

46. Effect of yeast extract and cAMP on appressorium formation Conidia of wild type on hydrophobic Gelbond Short germ tube 2% yeast extract Long Germ tube 2% yeast extract with 10mM cAMP Appressorium 24 Beckerman and Ebbole ( 1996)

47. An Anti-hydrotactic Response and Solid Surface Recognition of Germ Tubes of the RiceBlast Fungus, Magnaporthe grisea • LIN-ZHONG XIAOet al., (1997) 23

48. A droplet of conidial suspension in distilled water was placed on the gel surface and incubatedthe germ tubes grew into the gel. • LIN-ZHONG XIAO et al., (1997) 22

49. Dryconidia were directly placed on the gel surface and the gel was over-laid with liquid paraffin and incubated, the germ tubes grew into thehydrophobic phase. • LIN-ZHONG XIAO et al., (1997) 21

50. Appressorium Formation of Magnaporthe grisea on Hycel A-342with Different Hardness. • LIN-ZHONG XIAO et al., (1997) 20