Which of the following bacteria present in the soil produces a characteristic odor when it rains on heated soil?

Correct option is C

Ans. (c) Streptomycetes
Sol. Streptomycetes, particularly Streptomyces species, produce a characteristic earthy odor when it rains on dry, heated soil. This smell is due to the release of a compound called geosmin, which is produced by these bacteria as part of their metabolic processes. Geosmin is highly sensitive to moisture and is responsible for the pleasant "petrichor" scent after rainfall.
Explanation of each option:
· (a) Micrococcus – Incorrect, as Micrococcus bacteria are found in soil but do not contribute to the petrichor scent.
· (b) Staphymycetes – Incorrect, as this name is not associated with geosmin production or the characteristic smell of rain.
· (c) Streptomycetes – Correct answer. These bacteria release geosmin, producing the distinct earthy odor after rain.
· (d) Diplomycetes – Incorrect, as this is not a known bacterial genus linked to soil odor.