Early detection of gray mold in grape using conventional and molecular methods

Abstract

Botrytis cinerea affects grape quality and yield, and can be difficult to manage due in part to non-symptomatic, quiescent infection in berry development. The aim of this study was to develop a dual system for the detection, isolation and quantification of B. cinerea. After three days of samples replication on the modified selective medium (mKERS), the results showed a significant infection effect on the majority of inflorescence samples, especially on the small berries which demonstrated Botrytis infection in all tested plants and appeared to be highly susceptible to Botrytis infection prior to harvest. Moreover, infection variation was determined in almost all inflorescence samples taken from different plants. The real-time PCR assay was used to determine the DNA quantity of B. cinerea in each sample tested. A linear relationship was found in these two systems, conventional and molecular assays, to demonstrate the infection of different samples with B. cinerea. Although, the real-time PCR assay was highly expensive, it appeared to be more rapid and sensitive than the conventional selective medium assay, allowing both detection and quantification of B. cinerea within 3 h. However, conventional assay has an advantage of both detection and isolation of viable cells of B. cinerea, which resulted in making a wide collection of different isolates. Furthermore, this conventional assay is cheaper than molecular test, especially when we carry out a routine work. This dual method proved to be selective and sensitive assays and should be used to monitor Botrytis infection in the field.

Key words: Botrytis cinerea, inflorescence infection, latent/quiescent infection, real time polymerase chain reaction/real-time quantitative PCR (PCR/qPCR).