Phytoplasma are prokaryotic, cell-wall less bacteria that infect the phloem of plants and are transmitted by insect vectors. They lack the ability to be cultured independently and are pleomorphic, ranging from 0.17-0.25 μm in size. Phytoplasma cause diseases in hundreds of plant species and are characterized by symptoms such as phyllody, yellowing, witches' brooms, and little leaf. They are detected using PCR and fluorescent staining. Major phytoplasma diseases include little leaf disease of brinjal, sesame phyllody, and lethal yellowing of coconut.

1. PHYTOPLASMA
N.H. SHANKAR REDDY
2ND PH.D. PLANT PATHOLOGY
ANNAMALAI UNIVERSITY

2. • Phytoplasma are prokaryotic unicellular,
gram +ve, pleomorphic and non motile
• They lack cell wall but bounded by a
membrane & have cytoplasm, ribosomes
and strands of nuclear materials.
• Phytoplasmas are mollicutes comes under
the division Tenericutes of kingdom
Protista.

3. • Discovered by Doi et al. (1967) in the phloem of mulberry plants and named as
MLO (mycoplasma like organism), later name changed to Phytoplasma in 10th
international congress of mycoplasmology.

4. Properties
• They belonging to the order Acholeplasmatales, and genus Phytoplasma, is at Candidatus
stage.
• Contains both DNA, RNA along with ribosomes as genetic material, size ranges from 0.17 –
0.25µm Genome size ranges from 530–1350 kb, with low G+C content of DNA (23–29.5
%).
• Generally, present in sap of phloem sieve tubes. It cannot be cultured on nutrient agar
medium, that why it referred called as ‘Candidatus Phytoplasma’ (candidatus means cannot
be cultured), but phytoplasma can grow in alimentary canal, haemolymph, salivary glands
and different body parts of their insect vectors.

5.  Phytoplasma have no flagella, and produce no spores. Cells can be differentiated
through bacteriological filter and Koch postulated have not been proved.
 Two common symptoms of phytoplasma infection are Phyllody (floral parts are
converted into leaf like structure), yellowing of leaves (colour of leaves due to
disrupt of transport of carbohydrates)
 Phytoplasma is mainly transmitted by leafhopper (family - Cicadellidae), but
plant hoppers (family - Fulgoridae) and psyllids are also been reported as
vectors.
 Detected by using PCR (based on 16sr DNA) and fluorescent staining with either
the DNA -specific stain 4,6-diamidino-2-phenylindole (DAPI) or the callose
specific stain aniline blue or Dienes’ stain.

6. Eg – Little leaf of brinjal (Leaf hopper - Hishimonus phycitis, Amrasca biguttula)
• Sesame phyllody (Leaf hopper -Orosius albicinctus)
• Grassy shoot of sugarcane (Leaf hoppers - Saccharosydne saccharivora)
• Coconut lethal yellowing (Plant hopper - Myndus crudus/ Haplaxius crudus)

7. List of phytoplasma diseases
1. Rice yellow dwarf
2. Rice orange leaf
3. Rice stripe
4. Grassy stunt of Rice
5. Giallume yellows of Rice
6. Potato witches broom
7. Potato phyllody
8. Purple top roll of potato
9. Marginal Flavescence of potato
10. Purple top wilt of Potato
11. Potato Stolbur
12. Sesamum phyllody
13. Little leaf of Brinjal
14. Grassy shoot of Sugarcane
15. Sandal spike
16. Peach X disease
17. Peach yellows
18. Lethal yellowing of coconut
19. Root wilt of coconut
20. Apple Rubbery wood
21. Aster yellows
22. Mulberry dwarf
23. Witches broom of neem
24. Paulownia witches broom
25. Little of eucalyptus
26. Phyllody of marigold
27. Phyllody of Phlox
28. Yellows of Catharanthus roseus
29. Bushy stunt of Grewia asiatica
30. Jujube witches broom.
31. Grapevine yellows
32. Safflower phyllody
33. Rosette of Pegion pea
34. Little leaf of bottle brush
35. Clover dwarf
36. Onion yellow dwarf
37. Sweet potato witches broom
38. Plantago witches broom
39. Bush clover witches broom
40. Sumach witches broom
41. White leaf disease of sugarcane
42. Alfa alfa witches broom
43. Beet yellow wilt
44. Celery yellows
45.Citrus vein – phloem degeneration
46. Cotton virescence
47. Cotton small leaf
48. Groundnuts witches broom
49. Legume little leaf
50. Oat sterile dwarf
51. Pear decline