Citrus Leprosis; a complex viral disease Ron Brlansky • Citrus leprosis (CL) is an economically important viral disease affecting citrus. • Leprosis is widely distributed in South and Central America, from Argentina to Mexico. • The disease is associated with different non-systemic viruses, which cause similar symptoms in the citrus hosts • The viruses are transmitted by false spider mites of the genus Brevipalpus; however the viruses have different genomes Symptoms of Citrus Leprosis • Localized symptoms in leaves, stems, and fruits. • In leaves, characteristic lesions are often circular (from 5 to 12 mm in diameter), chlorotic or necrotic, colored light yellow to dark brown. • In older lesions, a darker central point can also be observed. • In young stems, lesions are small, chlorotic and shallow but with time they become darker brown or reddish and prominent. • In old stems lesions can join together and appearing larger. • In fruits, dark and depressed lesions are found in large numbers and affecting only the external part. • Commercial losses result from undesirable appearance of fruits, premature absission of fruit and leaf loss with canopy thinning Symptoms of Citrus Leprosis • Chlorotic leaf lesions becoming brown with or without necrotic centers • Flat or slightly raised necrotic areas on twigs and leaves • Flat or depressed lesions on fruit with concentric patterns and gumming • Abscission of leaves and fruit and twig dieback due to extensive lesion development Citrus Leprosis Symptoms in Panama Citrus Leprosis Symptoms in Columbia Citrus Leprosis Disease Symptoms in Colombia 2011 Nuclear Leprosis Symptoms Types of Citrus Leprosis • Defined by where the virus is found in the cell • Nuclear – in the nucleus and cytoplasm • Cytoplasmic – only in the cytoplasm • Virus sequence Nuclear A B M NM CW N NI V Cytoplasmic A B CW CW CW Timeline on Leprosis • 1940. A leprose dos citrus –Discusses a disease called leprosis • 1955. Estudos sobre a leprose dos citros. I-Distribuição geográfica e sintomatologia • 1968. Studies on the etiology of leprosis in citrus. (in Florida) • 1972 Short, rod-like particles associated with citrus leprosis (nuclear) • 1995. Ultrastructural studies of citrus leprosis virus showed the virions only in the cytoplasm (cytoplasmic). Hence 2 types seen, nuclear & cytoplasmic • 2000. Transmission of Citrus Leprosis Virus by Brevipalpus phoenicis (Acari: Tenuipalpidae) • 2003. Citrus leprosis virus vectored by Brevipalpus phoenicis (Acari: Tenuipalpidae) on citrus in Brazil and the cytoplasmic type virion is the most prevalent one. • 2006 Complete nucleotide sequence, genomic organization and phylogenetic analysis of Citrus leprosis virus cytoplasmic type in Brazil • 2006. The cytoplasmic virus was considered in the Rhabdoviridae family and is now classified as the type member of Cilevirus. • 2006 Occurrence of cytoplasmic citrus leprosis virus in Colombia but symptoms reported in 2003-04. • 2008 Natural infection of Swinglea glutinosa by the cytoplasmic type (CiLV-C) in Colombia • 2010 Citrus Leprosis: Centennial of an unusual mite-virus pathosystem (Review) • 2013 A novel virus of the genus Cilevirus causing symptoms similar to citrus leprosis in Colombia(cytoplasmic citrus leprosis 2 (CiLV C2) • 2013. Characterization of a virus infecting Citrus volkameriana with citrus leprosis-like symptoms in Hawaii (CiLV-C2 Hibiscus strain) • 2013 A leprosis-like cytoplasmic virus found infecting ornamental hibiscus in Hawaii. Now Hibiscus green spot virus 2 (HGSV-2) • 2013. Citrus leprosis virus nuclear type from Mexico reveals a close association with orchid fleck virus, (OFV citrus strain 1) • 2014. First report of Citrus leprosis virus nuclear type in sweet orange in Colombia • 2014. Characterization of a proposed dichorhavirus associated with the citrus leprosis disease in Mexico (nuclear leprosis) • 2015. Identification and molecular characterization of nuclear Citrus leprosis virus infecting multiple Citrus species in Mexico • 2015 Complex relationships between viruses, hosts, and vectors related to citrus leprosis, an emerging disease • 2015 History and Diversity of Citrus Leprosis Virus Recorded in Herbarium Specimens (Citrus nuclear leprosis (CiLV-N0) from Florida found) • 2016 Cytoplasmic Isolate BR_SP_SJP_01: RNA1 and RNA2 sequences, clade SJP, 85.6% and 88.4%, similarity with CiLV-C but RNA2 5’-proximal region was a minor donor in a putative inter-clade recombination event. Infects Commelina benghalensis • 2017 Detection and differentiation of five cytoplasmic and three nuclear citrus leprosis associated viruses using conventional multiplex reverse transcription polymerase chain reaction (CiLV-C, CiLV-C2, SJRP isolate of CiLV-C, hibiscus infecting Cilevirus (CiLV-C2H) and Hibiscus green spot higrevirus -2 (HGSV-2) and Nuclear types N0, N and N2. • 2018. Identification and Characterization of Citrus Chlorotic Spot Virus, a New Dichorhavirus Associated with Citrus Leprosis-Like Symptoms • 2019 Citrus Leprosis Complex Cytoplasmic Nuclear Dichorhavirus (Bi-partite, - sense) Cilevirus (Bi-partite, + sense) Higrevirus (Tri-partite, + sense) • Orchid fleck virus-Citrus strain 1 • Citrus leprosis virus C Hibiscus green spot virus-2 (HGSV-2) • Orchid fleck virus-Citrus strain 2 • Citrus leprosis virus C SJP strain • Orchid fleck virus-2 • Citrus leprosis virus C2 • Citrus necrotic spot virus • Citrus leprosis virus C2 Hibiscus strain • Citrus leprosis virus N0 • Citrus leprosis virus N • Citrus chlorotic spot virus NB: I did not add OFV-1 in the Dichorhavirus list because there is no information of infection of OFV-1 in Citrus. OFV-2 infects citrus in South Africa and produced leprosis like symptoms Citrus Leprosis Virus Complex Cytoplasmic Nuclear Dichorhavirus (Bi-partite, - sense) Cilevirus (Bi-partite, + sense) Higrevirus (Tri-partite, + sense) • Orchid fleck virus-Citrus strain 1 • Citrus leprosis virus C Hibiscus green spot virus-2 (HGSV-2) • Orchid fleck virus-Citrus strain 2 • Citrus leprosis virus C SJP strain • Orchid fleck virus-2 • Citrus leprosis virus C2 • Citrus necrotic spot virus • Citrus leprosis virus C2 Hibiscus strain • Citrus leprosis virus N0 • Citrus leprosis virus N • Citrus chlorotic spot virus Citrus Leprosis Distribution 1960’s 1920 Leprosis or not? Virus or Mistaken Identity? A B NI CW Citrus Leprosis Virus (TEM) Hypersensitivity - Autophagy Response (TEM) Images courtesy of Dr. Ron Brlansky Fig. 1. A, Localized chlorotic symptoms in sweet orange (Citrus sinensis L.) leaves infected with citrus chlorotic spot virus (CiCSV). B, Mature spots or older lesions may have necrotic areas (two leaves at the right). C, Localized chlorotic symptoms in beach hibiscus (Hibiscus tiliaceus L. syn. Talipariti tiliaceum (L.) Fryxell) leaves infected with CiCSV. Published in: C. Chabi-Jesus; P. L. Ramos-González; A. D. Tassi; O. Guerra-Peraza; E. W. Kitajima; R. Harakava; J. E. A. Beserra Jr.; R. B. Salaroli; J. Freitas-Astúa; Plant Disease 2018, 102, 1588-1598. Copyright © 2018 The American Phytopathological Society • DOI: 10.1094/PDIS-09-17-1425-RE Fig. 1. A, Localized chlorotic symptoms in sweet orange (Citrus sinensis L.) leaves infected with citrus chlorotic spot virus (CiCSV). B, Mature spots or older lesions may have necrotic areas (two leaves at the right). C, Localized chlorotic symptoms in beach hibiscus (Hibiscus tiliaceus L. syn. Talipariti tiliaceum (L.) Fryxell) leaves infected with CiCSV. Published in: C. Chabi-Jesus; P. L. Ramos-González; A. D. Tassi; O. Guerra-Peraza; E. W. Kitajima; R. Harakava; J. E. A. Beserra Jr.; R. B. Salaroli; J. Freitas-Astúa; Plant Disease 2018, 102, 1588-1598. Copyright © 2018 The American Phytopathological Society • DOI: 10.1094/PDIS-09-17- 1425-RE Vectored by Brevipalpus mites A B Brevipalpus californicus sensu lato (A) Dorsal of ventral overview. (B) Ventral overview (C) Dorsal of ventral D Propodosoma (D) C Ventral Opisthosoma (EM Mag 600X).