​Appressorium is expected to be formed during which one of the following diseases?​

Correct option is C

The correct answer is Powdery mildew in pea. An appressorium is a specialized infection structure formed by certain fungal pathogens during the infection process. It is particularly formed by the fungi responsible for powdery mildew, a common plant disease caused by obligate biotrophic fungi. In the case of pea plants, the powdery mildew fungus forms an appressorium on the surface of the plant tissue, which facilitates penetration and subsequent infection. Appressoria are specialized structures that enable the fungus to exert mechanical force or secrete enzymes to penetrate the host plant cell walls.

Information Booster

1. An appressorium is a specialized structure formed by fungi, especially obligate biotrophs like those causing powdery mildew.
2. The appressorium facilitates penetration by exerting physical force or secreting enzymes that break down the plant cell wall.
3. Powdery mildew fungi form these structures on the surface of leaves, stems, and other parts of plants to initiate the infection.
4. The formation of an appressorium is typically observed in fungal pathogens like Erysiphe species, which are responsible for powdery mildew.
5. Appressorium formation is a critical step in the infection cycle of the fungus, as it leads to the establishment of a feeding structure called the haustorium.
6. Powdery mildew affects many plants, including peas, tomatoes, and other crops, and the appressorium plays a major role in disease progression.

Additional Information

• Option (a): Bacterial leaf blight in rice is incorrect because bacterial pathogens do not typically form appressoria. Bacterial infections in rice are caused by bacteria such as Xanthomonas oryzae, which do not form appressoria for infection.
• Option (b): Bacterial wilt in tomato is incorrect because, like in rice, bacterial wilt in tomatoes is caused by bacteria, and bacterial pathogens do not form appressoria.
• Option (d): Leaf curl disease in tobacco is incorrect because leaf curl disease is caused by viruses, not fungi, and viral pathogens do not form appressoria.