Question

Which of the following is not caused by mycoplasmas?

• A. Little leaf of brinjal
• B. Bunchy top of papaya
• C. Citrus canker
• D. Witches-broom of potato

Answer 1

The correct option is C Citrus canker

Phytoplasmas are plant mycoplasma like organisms (plant MLO) that lacks cell wall but have rigid plasma membrane and exhibit pleomorphy. Little leaf of brinjal is caused by phytoplasma and is characterized by extreme reduction in leaf size and excess growth of axillary shoot with short internodes. Bunchy top of papaya is caused by MLO and is characterized by faint mottling of upper leaves, reduced growth of leaves, petiole and internode followed by cessation of apical growth to give “bunchy top”. Witches-broom of potato condition caused by phytoplasma and is characterized by loss of apical dominance of the branches and phyllody. Citrus canker is not caused by mycoplasmas but by the bacterium Xanthomonas axonopodis.

Thus, the correct answer is option C.