Disease Caused by Mycoplasma
1. They are known to cause “Yellows” disease in plant.
2. Economically important plant disease caused by mycoplasms are sandle spike aster yellows, mulberry dwarf , grassy shoot of sugarcane , citrus greening, seasamum phyllody , little leaf of brinjal, etc.
3. They cause disease in human and animals. E. g Pneumonia.
Spiroplasma are helical prokaryotes lacking a rigid cell wall, but bounded by unit membranes 8-10 µm in thickness, with RNA granules and DNA strand in the nuclear region.
They vary in shape from spherical to slightly ovoid to helical and branched non helical structure. Unlike Phytoplasma, they can be cultured on artificial media, colonies on agar have 0-2 mm diameter and appears as granules but some have fried egg appearances. They do µµµnot have any flagella but have rotary mortality and reproduce by fission. They transmitted mostly by leaf hoppers. They are resistant to penicillin but inhibited by tetracycline.
Citrus stubborn (Spiroplasma citri), Leaf roll, yellow dwarf of rice, Pear decline, Corn stunt, etc.