Guazuma ulmifolia (Sterculiaceae), a new natural host of 16SrXV phytoplasma in Costa Rica

Abstract

Guacimo trees (Guazuma ulmifolia, Sterculiaceae) showing witches' broom symptoms (GWB), small leaves, short internodes, stunting and no flower and fruit production were observed on side roads and fences in different areas of Costa Rica. The occurrence of phytoplasma infection in GWB trees was evaluated by transmission electron microscopy (TEM), and by molecular analyses based on 16S rDNA: nested-PCR/RFLP, sequencing and phylogenetics. Phytoplasmas were observed only in the sieve cells of symptomatic trees by TEM. The infection was confirmed by nested-PCR; amplicons of about 1.2 kb were obtained from all DNA samples from symptomatic trees. The RFLP analysis generated patterns identical among GWB samples and showed a relationship of this phytoplasma to hibiscus witches' broom group (16SrXV). The 16S rDNA sequence (1460 nt), obtained from the P1A/16S-SR semi-nested-PCR products of two phytoplasma strains, shared 98.8% similarity with 'Candidatus Phytoplasma brasiliense' (GenBank accession: AF147708). The virtual RFLP pattern indicated a similarity coefficient of 0.95 with 16Sr group XV-A (AF147708), suggesting that the GWB phytoplasma may represent a new subgroup within this group. This is the first report of a phytoplasma infecting the neotropical tree species G. ulmifolia and the natural occurrence of a phytoplasma strain closely related to 'Ca. Phytoplasma brasiliense' in Costa Rica. Key words: 'Ca. Phytoplasma brasiliense', 16S rRNA, guacimo witches'-broom, nested-PCR, RFLP. RESUMEN Guazuma ulmifolia (Sterculiaceae), un nuevo hospedero natural de fitoplasmas del grupo 16SrXV en Costa RicaEn varias zonas de Costa Rica se observaron árboles de guácimo (Guazuma ulmifolia, Sterculiaceae) con síntomas de escoba de bruja (GWB), hoja pequeña, acortamiento de entrenudos, dando al árbol un aspecto general de enanismo. La infección por fitoplasmas en los árboles de guácimo se evaluó mediante microscopia electrónica de transmisión (TEM), análisis moleculares del 16S rDNA mediante PCR anidado, RFLP´s, secuenciación y filogenia. En la TEM, los fitoplasmas se observaron sólo en las células del floema de los árboles sintomáticos. La infección se confirmó por PCR anidada, los productos amplificados de aproximadamente 1,2 kb se obtuvieron para todas las muestras sintomáticas evaluadas. El análisis de RFLP generó patrones idénticos entre las muestras con GWB y mostró relación de este fitoplasma con el de la "escoba de bruja del hibisco" (16SrXV). La secuencia de ADNr 16S (1460 nt) de los productos obtenidos por PCR semi-anidado (P1A/16S-SR) de dos muestras de GWB mostraron 98,8% de similitud con "Candidatus Phytoplasma brasiliense" (GenBank, registro AF147708). El patrón RFLP virtual reveló 95% de similitud con el grupo 16Sr XV-A (AF147708), lo que sugiere que el fitoplasma GWB puede representar un nuevo subgrupo dentro del 16Sr XV. Este es el primer informe de un fitoplasma infectando a la especie neotropical G. ulmifolia y de la ocurrencia natural de un fitoplasma estrechamente relacionado con "Ca. Phytoplasma brasili...

Phytoplasmas and Phytoplasma Diseases: A Severe Threat to Agriculture

“…P. brasiliense' AF147708 [198] XV-B Guazuma witches' broom (GWB) HQ258882 [199] 16SrXVI: Sugarcane yellow leaf syndrome (America) -The ribosomal group has no designation since only Genbank sequences were employed for its determination.…”

Guazuma ulmifolia Lam. Decreases Oxidative Stress in Blood Cells and Prevents Doxorubicin‐Induced Cardiotoxicity

“…Guazuma ulmifolia Lam. (Malvaceae), commonly known as “mutamba” [ 16 ] or “guácimo” [ 17 ], is found in Latin American countries, including Brazil [ 18 ]. In traditional medicine, it is used as an infusion or decoction to treat inflammation [ 19 ], gastrointestinal diseases [ 20 ], and diabetes [ 21 ], which are associated with oxidative stress [ 2 – 4 ].…”

Catharanthus roseus (Apocynaceae) naturally infected with diverse phytoplasmas in Costa Rica

“…(Montano et al, 2001a), and other hosts including C. roseus, Crotalaria juncea Brassica oleracea, and Sida rhombifolia (Montano et al, 2001b;Eckstein, Barboza, Rezende, & Bedendo, 2011;Bianco, et al, 2014;Canale, & Bedendo, 2013). It is also present in Costa Rica infecting Guazuma ulmifolia (Villalobos, et al, 2011), and in Peru infecting Vitis vinifera and C. papaya . The Costa Rican Guazuma strain was classified as subgroup 16SrXV-B and the Peruvian strain was identified as a variant.…”

“…Phytoplasma infection with one of four 16Sr groups (16SrI, 16SrIII, 16SrIX, and 16Sr XV) has been reported in various plant species in Costa Rica (Gámez & León, 1985;Kenyon, Harrison, & Richardson, 1999;Villalobos, Moreira, Bottner, Lee, & Rivera, 2002;Villalobos et al, 2011;Pardo, Truke, Cardozo, Varela, & Alvarez, 2014). Although natural phytoplasma infection in Catharanthus roseus G. Don (Apocynaceae) has been reported elsewhere (Pérez-López, Olivier, Luna-Rodríguez, Adame-García, & Dumonceaux, 2016b), to our knowledge, it has not been reported in Costa Rica.…”