Direct Colony Nested-PCR for the Detection of Fusarium oxysporum f. sp. PsidiiCausing Wilt Disease in Psidium guajava L.

Guava (Psidium guajava L.) is one of the important fruit crops which are grown in tropical and subtropical countries including India. Wilt is an important disease in guava which is caused by Fusarium oxysporum f. sp. psidii (Fop) as a major obstacle for guava fruit production. It is manifested symptomatically with alterations in the development process such as premature shedding of leaves, pre-maturation of fruits, entire/whole tree defoliation and eventually death of the plant. In this study a colony PCR assay was developed for direct amplification of Internal Transcribed Spacer (ITS) region of fungal rDNA of Fop isolates. For this, two sets of primers were developed for amplification of ITS region. . The sensitivity of both the primer pair was ranged up to 10-6 and 10-7 dilutions of the pure mycelium suspension. This study provides new insight for rapid, sensitive and specific molecular detection of Fop isolates, and also useful for earlier diagnostic for better management of guava wilt disease