5S Ribosomal RNA Gene Repeat Sequences Define at Least Eight Groups of Plant Trypanosomatids (Phytomonas spp.): Phloem‐Restricted Pathogens Form a Distinct Section

Abstract

Trypanosomatids isolated from plants have been assigned typically into the genus Phytomonas. Such designations do not reflect the biology of the diverse isolates; confusion may arise due to the transient presence in plants of monogenetic (insect) trypanosomatids deposited by phytophagous bugs. To develop further molecular markers for the plant kinetoplastids, we have obtained the DNA sequence of the 5S ribosomal RNA gene from 24 isolates harvested from phloem, latex, and fruit. Small, distinct sequence differences were found at the 3'-ends of the transcribed regions; substantial sequence and size differences were found in the non-transcribed regions. Alignment of the gene sequences from all the isolates suggested the presence of eight groupings. While six groups contained isolates from single plant tissues, groups C and A contained isolates from both fruit and latex. The DNA sequences of the 10 phloem-restricted pathogenic isolates from South America and the Carribean were highly conserved and thus comprised a single group (H). The conserved nature of the 5S ribosomal RNA genes in these plant pathogens supports the proposal that they be considered as a distinct section, the phloemicola.

Evidence That a Laminin-Like Insect Protein Mediates Early Events in the Interaction of a Phytoparasite with Its Vector's Salivary Gland

“…Species of the genus Phytomonas are found in a wide range of geographical areas, including Northern and Central Africa, China, India, several European countries, and on the American continent [1]–[4]. The parasitism may occur without any apparent pathogenicity in the plants, but may also cause devastating diseases in plantations of economic significance.…”

Kinetoplast DNA minicircles of phloem-restricted Phytomonas associated with wilt diseases of coconut and oil palms have a two-domain structure

“…The previously described Phytomonas spp. isolates used for PCR ampli¢cation are: Ps1G [16]; Lima.Pe, Berg.Br, E.hi.Sur, Mand.sc.Br, Tom.Sp, E.M.1, E.hi.Ind, E.hi.Sen, Mani.Br, E.hi.Vz, E.hy.Gu, Hart 1, Mar 1 and Ascl.cu.Vz [6] ; Aca [11]; Mar 6 [7]; Blepharodon, Rhabdadenia, Trifolium and Amaranthus [5]. Previously undescribed Venezuelan isolates from Euphorbia heterophila (E.het.Vz) and Euphorbia prostata (E.pro.Vz) were collected by M.D.…”

Diversidade, relações filogenéticas e taxonomia de Phytomonas spp.

“…O gene SL foi utilizado para analisar o polimorfismo genético em vários gêneros de tripanossomatídeos, incluindo Trypanosoma (Ventura et al, 2001; Maia da Silva et al, 2007;Rodrigues et al, 2010), Crithidia (Fernandes et al, 1997;Yurchenko et al, 2008), Endotrypanum (Fernandes et al, 1993), Leishmania (Fernandes et al, 1994;Paiva et al, 2006;Serin et al, 2007), Leptomonas e Herpetomonas (Podlipaev et al, 2004a;Westenberger et al, 2004;Yurchenko et al, 2006) e Phytomonas (Godoi et al, 2002;Nunes et al, 1995;Teixeira et al, 1996;Serrano et al, 1999b,c;Dollet et al, 2000Dollet et al, , 2001Dollet, 2001). …”

“…Phytomonas, bem como do grupo restrito ao floema, possibilitando a divisão em grupos e subgrupos, e demonstrando a sensibilidade do gene SL para examinar o polimorfismo genético intra-grupos (Dollet et al, 2000(Dollet et al, , 2001. A SSU e LSU (sequências altamente conservadas) são intercaladas por regiões mais polimórficas, os espaçadores externos transcritos (ETS) e espaçadores internos transcritos (ITS) (Hernández et al, 1990;Sogin et al, 1986).…”

“…As sequências obtidas de ITS rDNA foram alinhadas com todas as disponíveis no GenBank (Dollet et al, 2012 (Serrano et al, 1999a;Dollet et al, 2000Dollet et al, , 2012Sturm et al, 2007). Entretanto, ao contrário desses estudos anteriores que criaram novos grupos simplesmente separando isolados com pequenas divergências, no nosso estudo os clados foram definidos pelo valor de suporte incluindo sequências mais divergentes, porém, de isolados filogeneticamente relacionados.…”