The white rust fungus, Albugo species, is the water mold and plant pathogen which attacks a variety of vegetables. It is a big concern for the farmers.

Asexual reproduction is the main way Albugo reproduces. Its hyphae is developing a bedlike mass between the mesophyll cell and epidermis cell of the host. Sporangia will be produced continually at the enlarged tip of the hyphae which will cause the epidermis to uplift and rupture eventually, releasing the mature sporangia.

Cheuk Ki: thanks for your additional information.