Question

Common bread mould is
(a) Aspergillus
(b) Penicillium
(c) Erysiphe
(d) Rhizopus

Answer 1

Hint: The organism is a Zygomycota member and can grow in both the tropical and subtropical regions. It grows mostly in the indoor environment and is a saprophyte.

Complete answer:
Rhizopus stolonifer is popularly referred to as black bread mould. It is a member of Zygomycota and has been considered the most important species in the Rhizopus genus.
It is a member of Zygomycota and has been considered the most important species of the genus Rhizopus. It is one of the world's most common fungi and has a global distribution although it is found most often in tropical and subtropical regions. It is a common agent of stored food decomposition. Like other members of the Rhizopus genus, R. Stolonifer is fast-growing, mostly indoor environments.
It is observed on mouldy materials of all kinds. Sometimes it is one of the first moulds to be observed on the surface of the stale bread. It can live both in soil and air. This species colonizes several natural substrates, since R. Stolonifer can tolerate large variations in the concentration of essential nutrients, and may use combined carbon and nitrogen in various forms.

Additional Information:
Apart from affecting the bread, the Rhizopus stolonifer causes a disease that occurs predominantly on ripe fruit such as strawberries, melon, and peach, which are more susceptible to wounds and have higher sugar content. The infected fruits become soft after a couple of days and release juices with an acidic odor. When the humidity and temperature are favorable, mycelial growth occurs rapidly on the infected fruit surface and the disease causes long mycelial stolons with black sporangia and spores to develop. When the fungus germinates, various types of esterases, including cutinase, are produced which help the fungus to penetrate the plant cell wall. If spread by wind or insect, the disease may also affect other healthy fruits adjacent to it.

So, the correct answer is ‘Rhizopus’.

Note:
Some species of Syncephalis can decrease asexual reproduction of Rhizopus Stolonifer, and thus the disease caused by this fungus can be postponed or even avoided. Fengycin, an antifungal complex, also triggers the death of fungal cells by necrosis (bursting of cells) and apoptosis (programmed cell death). Treatment with sodium ortho phenyl phenol (Stopmold B) and dichloran (Botran W) in sweet potatoes has effectively minimized storage rot.