Molecular detection and identification of a phytoplasma associated with cinnamon (Cinnamomum cassia B.) witches’ broom disease in Quang Ngai province, Vietnam

Abstract

Cinnamon (Cinnamomum cassia B.) is an important crop in Vietnam for domestic consumption and exportation. In recent years, a disease known as cinnamon witches’ broom (CinWB) has been discovered on cinnamon grown in Tra Bong district - Quang Ngai province. The typical symptoms of CinWB were the formation of small tumors on the stems, branches, petioles, and veins of plants. The tumors become long squid-like tassels giving the appearance of a witches’ broom. Infected plants are stunted, with delayed growth and development, causing a high reduction in the yield and quality of farmed cinnamon. In the present study, nested-PCR was applied with the universal primer pairs P1/P7 and R16F2n/R16R2. PCR products of an approximate size of 1200 bp were amplified from the twelves CinWB-showing samples collected from Tra Bong district, Quang Ngai province. All PCR products were directly sequenced in both directions using R16F2n and R16R2 primers. A BLAST search indicated that DNA sequences of all 12 PCR products were identical and show 99% identity with phytoplasma sequences of the 16SrXIV group. And the CinWB phytoplasma isolated from the CinWB-showing cinnamon from Tra Bong district - Quang Ngai province (QQNVN) was deposited in GenBank under an accession number JX413793.