Cellulose synthase 3 (Phytophthora infestans) (PiCesA3)

Cellulose synthase 3 (PiCesA3) is an essential enzyme in the oomycete pathogen Phytophthora infestans, responsible for the biosynthesis of cellulose, which serves as a critical structural component of the pathogen's cell wall [1, 9]. Unlike true fungi that primarily utilize chitin, oomycetes rely heavily on cellulose to maintain cell wall integrity and support life stages such as hyphal growth and the formation of pre-infection structures called appressoria [8, 10]. PiCesA3 belongs to the glycosyltransferase family 2 (GT2) and is the primary molecular target for carboxylic acid amide (CAA) fungicides, including mandipropamid and dimethomorph [1, 3]. These fungicides act by inhibiting the catalytic activity of the enzyme, leading to defective cell wall construction and eventual osmotic lysis of the pathogen [1, 3]. Resistance to these agents is commonly linked to specific point mutations in the PiCesA3 gene, particularly at the glycine residue at position 1105 [1, 4]. Because cellulose biosynthesis is absent in vertebrate systems, PiCesA3 represents a highly selective target for controlling late blight, one of the most destructive diseases in global potato and tomato production [8].

Other names

PiCesA3CesA3Cellulose synthase catalytic subunit 3Cellulose synthase-like PiCesA3Cellulose synthase A3

Inhibition of cellulose synthase activity leading to disruption of cell wall biosynthesis and subsequent cell lysis