Phenotypic Characterization and Molecular Phylogenetic Relationship of Erysiphe necator Infecting Grapes (Vitis vinifera)

Abstract

Grapes powdery mildew is caused by the most destructive pathogen Erysiphe necator leading to severe yield losses around the world.  In order to study the phenotypic and molecular characters, the powdery mildew infected leaf samples were collected from eight different places in Coimbatore and Theni districts in the state of Tamil Nadu India. The identity of the pathogen as E. necator was established by microscopic studies and the isolates were further confirmed molecularly by amplification of Internal transcribed spacer (ITS) and Cytochrome b gene (Cyt b). Further molecular confirmation was obtained by characterizing Cytochrome b. An amplicon size of ~ 367 and ~ 470 bp were obtained from amplification with Uncin144 and Uncin511 and Cyt b F and Cyt b R gene primers respectively. The identity for cyt b gene segment was 96 to 98%, similarity with E. necator isolates deposited in NCBI genbank (KY418048.1, KY418049.1). A phylogenetic tree was constructed on the basis of nucleotide sequence of cytochrome b gene of the study isolates as well as E. necator and other Erysiphe species in NCBI database. From the tree it was evident that the study isolates from Tamil Nadu, India were very distinct from other E. necator isolates deposited in NCBI genbank database.