Identification of an Australian-like dicot-infecting mastrevirus in Pakistan.

Abstract

Although members of five distinct viral species in the genus Mastrevirus (family Geminiviridae) infect dicotyledonous plants in Australia, in the remainder of the world, only a single dicot-infecting mastrevirus, chickpea chlorotic dwarf virus (CpCDV) has ever been identified. This virus has been found infecting leguminous hosts in Africa, the Middle East and the Indian subcontinent. To further explore the diversity of CpCDV in Pakistan, ten full mastrevirus genome sequences from chickpea and lentil plants were determined. Eight of these genomes were from previously described CpCDV strains and included the first reported strain D and H isolates in Pakistan. Two other genomes derived from infected chickpea plants are more closely related to dicot-infecting mastreviruses found in Australia than they are to CpCDV. These two divergent genomes shared less than 75% genome-wide nucleotide sequence identity with other characterised mastreviruses and therefore are likely to belong to a second species of dicot-infecting mastreviruses outside of Australia. We propose naming this species Chickpea yellow dwarf virus. We discuss how the presence of chickpea yellow dwarf virus (CpYDV) in Pakistan weakens the hypothesis that Australia is the geographical origin of the dicot-infecting mastreviruses.