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- 1. - SYMPTOMS OF BACTERIAL DISEASES AKSHAYA.CK ASST. PROF. (PLANT PATHOLOGY
- 2. BACTERIA Microscopic, Single celled Prokaryotic Achlorophyllous Commonly reproduced by bin fission Beneficial and harmful Mostly gram negative bacteria – plant pathogenic
- 3. ▣Bacterial DNA floats free twisted thread like mass– nucleoid ▣Circular DNA of bacteria – plasmid ▣Types of plasmid ▣F-plasmid- code for proteins of sex pili ▣R plasmid- carry genes that provide resistance to antibiotics like tetracycline & heavy metals ▣Bacteriocinogens/ col factors- carry genes for bacteriocinsmproteins killing closely related bacteria ▣Virulence plasmid – produce toxins in disease ▣Tumor plasmid/ Ti plasmid – responsible for tumor formation in plants (now used in genetic engineering) ▣Catabolic plasmid – contains genes for catabolic enzymes
- 4. CLASSIFICATION -BASED ON ❖ shape ❖ staining character ❖ Arrangement of flagella ❖ Nutrition requirements ❖ Oxygen requirement ❖ Temperature depends ❖ Phylogenic relationship
- 13. BASED ON STAINING CHARACTER Gram positive Gram negative
- 14. ▣ Cell wall made up of – Mucopeptide (Peptidoglycon) ▣ Cell wall of +ve bacteria (thick layer of Peptidoglycon 85% + Simple polysaccharide, like teichoic acids) ▣ Cell wall of -ve bacteria (thin layer of peptidoglycon (3-12% )+ Lipo protein + liposaccharides) ▣ The wall function like a sieve. The outer membrane contains proteins called porins ▣ Safranin/ carbolfuschin – retained by gram –ve.
- 15. Based on arrangement of flagella Monotrichous Amphitrichous Lophotrichus Peritrichous Atrichous
- 17. BASED ON NUTRITION REQUIREMENT Phototrophs • photolithotrophs(photoautotrophs)-green sulful bacteria •Photoheterotrophs (photoorganotrophs) non –sulfur bacteria Chaemotrophs – chemolithotrophs (chemoautotrophs)nitrifying bacteria - nitrosomonas •Chemohetrotrophs E.coli •Symbionts - Rhizobium
- 18. BASED ON OXYGEN REQUIREMENT Aerobes Anaerobes Obligate Facultative anaerobes
- 19. BASED ON TEMPERATURE Thermophilic – above 40 degree C Mesothermic – 25 to 40 degree C Psychrothermic – below 25 degree C
- 20. BACTERIAL GROWTH CURVE Lag phase Exponential or log phase Stationary phase Decline or death phase
- 22. REPRODUCTIO N Asexual Binary fission , Endospore formation, cyst fragmentation Sexual Conjugation Transformation Transduction
- 23. FISSION
- 25. CYST FRAGMENTATION • Cyst – less resistant than endospores • The whole cells transformed into cyst • Cysts are formed in Azatobacter & Myxobacteria E.g. Myzococcus , Chondromyces • Fragmentation is common in Actinomycetes
- 26. Conjugation • 1946 – Lederberg & Tatum discovered in E.coli • Physical contact involved , the DNA passed from one cell to another cell through a conjugation tube. • One acting as donor- male • Another as recipient of genes (female)
- 27. Conjugation
- 28. Transformation • Transformation- 1928,Fred Griffith observed the phenomenon in the bacterium Pneumonococcus • Transformation the phenomena occur in heat killed bacteria
- 29. Transformation
- 30. Transduction • Zinder & Lederberg,1952 observed transduction in salmonella • Bacteriophage plays important role in it • Bacteriophage – the virus that kills / eating bacteria • The bacteriophage in transduction mechanism which contains ppiece of bacterial DNA are called as Transducing phages
- 33. ▣ Protoplast –A protoplast is a completely wall free cell which is bound only by the plasmalemma. It lacks all the properties of a cell which associated with in cell wall ▣ Sphaeroplast – it is a bacterial cell with damaged cell wall. The wall is not completely removed. Therfore, of the properties of the cell wall are lost. ▣ L form bacteria – is a protoplast or sphaeroplast like body capable of growth and multiplication in this form
- 34. BACTERIAL PLANT PATHOGENS • The American Thomas J. Burrill (1839 - 1916) of the University of Illinois was the first to describe a bacterial disease in plants when 1878 - 1884 he showed that fire blight of pears and apples was caused by the bacterium now known as Erwinia amylovora.
- 35. BACTERIA • Bacteria are unicellular and one of three shapes; round (coccus, spherical or ovoid); • All plant pathogenic bacteria are rod-shaped • About 200 out of the total 1600 known bacterial species are recognized as plant pathogens.
- 36. BACTERIA
- 37. BACTERIAL SPOTS AND BLIGHTS • The most common types of bacterial symptom on plants are those that appear as spots of various sizes on leaves, stems and fruits. • Bacterial spots appear as necrotic, usually circular or roughly circular and in some cases they are surrounded by a yellowish halo. • In dicotyledonous plants the development of some bacterial spots is restricted by intermediate or large veins and the spots appear typically angulareg.Angularleafspotofcotton • Bacterial spots on leaves and stems of monocotyledonous plants appear as streaks or strips.LEAFSTREAKOFPADDY • In leaf blight disease, the spots enlarge in size, rapidly necrotic, and through coalescence of several small spots, may produce large dead areas of various shapes. • Eg: Bacterial leaf spot of Tomato caused by Xanthomonas campestris pv. vesicatoria • Bacterial leaf blight of rice caused by Xanthomonas campestris pv. oryzae
- 38. BACTERIAL SPOTS AND BLIGHTS
- 39. Bacterial leaf Streak •Long, narrow necrotic lesions on leaves or stems •Translucent streaks are formed on the veins •Band like exudates
- 41. Bacterial leaf Blight • Appears at the time of heading • In nursery circular yellow spots in margin • Coalesce and cause drying of foliage • Kresek symptom • 1-2 weeks after transplanting • Enters through wounds, leaf tips • In grown up plants water soaked translucent spots, appear nearly margin of leaf-turn straw coloured, milky opaque dew drops seen
- 42. Bacterial ooze Exudates, consisting of bacterial cells, on the surface of plant parts infected with bacteria
- 43. Bacterial ooze Exudates, consisting of bacterial cells, on the surface of plant parts infected with bacteria
- 44. BACTERIAL BLIGHT
- 47. COTTON BACTERIAL BLIGHT XANTHOMONAS AXONOPODIS PV.MALVACEARUM • Seedling blight • Angular leaf spot • Vein blight (vein necrosis / black vein) • Black arm • Boll rot
- 48. • 1.Seedling blight On cotyledons, bacterial blight causes small, quarter-inch- diameter lesions that are initially dark green turning to dark brown. • 2.Angular leaf spot • Symptoms are observed on the leaves, stem and branches and on bolls. On leaves, angular brown to black water soaked spots are seen and the spots are restricted by veins. • 3.Veinal blight / Black vein • The infection spreads to the vein and the affected vein becomes black with bacterial ooze forming an encrustation on veins. This is veinal blight stage (black vein). • 4.Black arm • On the surface of stems and branches, elongate black lesions are observed. This causes breaking of the branches which hang on the affected plant. This is black arm stage. • 5.Boll rot. • On the surface of bolls, round to irregular black water soaked, sunken lesions develop. This causes premature opening and shedding of bolls. The lint turns yellow because of bacterial ooze. • The bacterium is a Gram negative, rod shaped
- 49. 5.Boll rot.
- 50. Oil soaked lesions STEM INFECTION VEINAL BLIGHT
- 51. SOFT ROTS • Rotting tissues become soft and watery, and slimy masses of bacteria and cellular debris frequently ooze out from cracks in the tissues. • At first symptom appears on the tissue as a water soaked lesion, which enlarge rapidly in diameter and in depth. • The objected area becomes discolored and some what depressed or it may appear wrinkled or blistered. • The margins of the lesions usually are well defined of first but later become obscure. • The tissue with in the appeared region become opaque in a short time or appear cream coloured and slimy disintegrating into a mushy mass of disorganized cells. • Eg: Soft rot of tomato, egg plant, carrots radishes, onion, cabbage, celery, lettuce is caused by Erwinia carotovora pv. carotovora
- 52. SOFT ROT IN CARROT
- 53. SOFT ROT IN POTATO
- 54. SCAB • At first scab appears as small brownish raised spots. • Later they enlarge, coalesce and become very corky. • In potato, the lesions extend below the tuber surface and when the corky tissue is removed 3-4 mm deep pits are present in the tuber. • Eg: Scab of potato caused by Streptomycis scabies
- 55. SCAB
- 56. GALLS • Galls are produced on stems and roots of plants. • The galls may be amorphous, consisting of other growths of more or less amporganized or disorganized plant tissues. • Bacterial carrying a tumor inducing (Ti) plasmid induce crown gall. • While bacteria carrying a root inducing (Ri) plasmid induce hairy root symptoms. • The gall-inducing bacteria enter plants through wounds and stimulate cells to divide and enlarge. • Eg: crown gall of rose caused by Agrobacterium tumefaciens • hairy root of apple caused by Agrobacterium rhizogenes.
- 57. GALLS
- 58. WILTS • In bacterial vascular wilts, bacteria enter, multiply in and more through the xylem vessels of the host plant. • During the infection time, interfere with the translocation of water and nutrients, and this results is the drooping, wilting and death of the above ground parts of the plants. • In bacterial wilts, the bacteria often destroy parts of cell walls of xylem vessels or cause them to rupture quite early in disease development. • But in fungal wilts the fungi remain almost exclusively in the vascular tissues • Eg: bacterial wilt of cucumber caused by Erwinia tracheiphila
- 59. BACTERIAL WILTS
- 60. CANKER • The lesions at first appear as small, slightly raised, water soaked, round spots, darker green than the surrounding tissue. • Later, the lesions become grayish white, rupture and appear spongy. • The margins of the lesions are sharply defined and are often surrounded by a yellowish halo. • Eg: Canker of citrus caused by Xanthomonas capestris pv. citri.
- 61. CANKER
- 62. CANKER
- 63. FIRE BLIGHT -ERWINIA AMYLOVORA • This disease is caused by bacteria. The symptoms are seen as distinct fire-like appearance on infected plant parts. • New shoots are highly susceptible to infection. The shoot tips wilt and droop without browning. • Secretion of golden coloured bacterial ooze is seen on the stem. • In fruits, Necrotic spots and oozing lesions are observed on the outer surface of the fruit surface.
- 64. MANAGEMENT OF FIRE BLIGHT • affected trees and host plants should be collected and burnt immediately on observing the incidence of fire blight. • Sprays of streptomycin -300ppm can control the infection in spring blossom of apple.
- 65. FIRE BLIGHT OF APPLE
- 66. FIRE BLIGHT OF APPLE
- 67. Thank you!