Viruses Infecting Papaya (Carica papaya L.): Etiology, Pathogenesis, and Molecular Biology

Abstract

During the last few decades, over 20 plant virus species capable of infecting papaya (Carica papaya L.) have emerged in tropical and subtropical regions. The extent and severity of disease symptoms vary widely from minor or unapparent to reduced tree vigor, yield, and impaired fruit quality. Existing data on molecular characteristics of viruses infecting papaya also vary; while phenotypic data are available for the majority, the genotype of many have not been characterized and partial or complete nucleotide sequences have not been determined. As a result, some virus species are classified in recognized taxa while others are tentatively assigned to genera or have not been sufficiently distinguished from viruses in recognized genera so as to form a new genus. This paper presents an overview of the virus species capable of infecting papaya, diseases they elicit, genetic structure and diversity, and factors contributing to their emergence where molecular data are available.