PERSIMMON (DIOSPYROS KAKI L.) AND JOHNSONGRASS [SORGHUMHALEPENSE (L.) PERS.] ARE NEW NATURAL HOSTS OF PEACH LATENT MOSAIC VIROID

Abstract

Peach latent mosaic viroid (PLMVd) naturally infects stone fruits worldwide. Here, we report the first detection of PLMVd in persimmon (Diospyros kaki L.) and a weed Johnsongrass [Sorghum halepense (L.) Pers.]. Samples corresponding to 12 persimmon specimens and weeds nearby the persimmon trees were collected from a germplasm collection plot in Malatya (Turkey). Total RNAs were isolated using a silica-based method and the complete viroid genome was amplified by reverse transcriptase polymerase chain reaction (RT-PCR). From these samples, PLMVd was detected in 7 of the 12 persimmons and in Johnsongrass revealing 8 new sequence variants. Multiple alignment and phylogenetic analyses revealed that identified persimmon and Johnsongrass isolates clustered only with PLMVd-walnut isolates previously identified from same locality. The nucleotide sequences of PLMVd persimmon and Johnsongrass isolates showed 96.71-99.11% similarity with the PLMVd isolates detected in different fruit crops in the world. A single specific mutation identified in two PLMVd persimmon variants (-TH2 and-TH10) effectively changed the predicted secondary structure of the agent. The identification and the genetic analyses of PLMVd variants in persimmon and Johnsongrass confirm that the agent is a ubiquitous and genetically variable viroid that infects cultivated fruit and weeds worldwide.