KNOWLEDGE REPOSITORY
3.2.5 IT Infrastructure Services: A Measurement of IT Infrastructure Capability
VIAMENTE ESTABLECIDAS DE Musa FHIA 21
Regeneración de plantas a partir de CES. Al mes de iniciado el proceso, se comenzó a evidenciar la forma- ción de embriones hasta llegar a la maduración en un período de dos meses (Figura 2A). La germinación de embriones a partir de embriones maduros se comenzó a dar al 45 meses (Figura 2B) y la formación de plantas se observó al 45 días después (Figura 2C).
Figura 2. (A) Embriones en desarrollo (RD1), (B) Germinación de embriones (RD2), (C) Formación de plántulas (RD2) Estos resultados demuestran que la metodología estandarizada por Shoofs, (1997) y validada en el laboratorio de micropopagación de plántulas de CORPOICA, fue efectiva para la regeneración de plántulas del cultivar FHIA 21 a partir de CES previamente establecidas.
CONCLUSIONES
1. A partir de plántulas in vitro de Hartón común, se obtuvo el mayor porcentaje de escalpos (43-72%) entre los pases 10-13 en medio P4, con una alta concentración de 6-BAP (22.5 mg/L).
2. Por el método de procesamiento de los escalpos, se logró obtener el 0.5% de callos ideales en condiciones de oscuridad a temperatura: 26ºC+/-2, en medio ZZs, en un período de 5 meses para Hartón común.
3. Se logró la obtención de agregados embriogénicos en medio líquido ZZl, dando inicio a la suspensión celular, disgregando el CI en Hartón común.
4. Se obtuvieron plántulas de FHIA 21 a partir de CES previamente establecidas, con la validación e implementación de protocolos con una capacidad de regeneración de 196 plántulas/mL de células establecidas.
AGRADECIMIENTOS
Yolanda Torres (Auxiliar Técnica del laboratorio de Micropropagación de plántulas - CORPOICA.), Consuelo Castrillón (Investigadora principal – Programa de Gestión e Innovación Tecnología – CORPOICA. Unidad local eje Cafetero) y Corporación PBA.
BIBLIOGRAFÍA
DHED’A. 1992. Culture de Suspensions Cellulaires Embryogéniques et Regeneration en Plantules par Embryogénésé Somatique chez le Bananier et le Bananier Plantain (Musa spp). Ph.D. Thesis, KULeuven, Belguium. 171p.
ESCALANT J.V., C.TEISSON AND F.X. COTE. 1994. Amplified Somatic Embryogenesis from Male Flowers of Triploid Banana and Plantain Cultivars (Musa sp). In Vitro Cell Biol Devpmt.30:181-186.
GEORGET, F; et al. 2000. Morphohistological Study of the Different Constituents of a Banana (Musa AAA, cv. Grande naine) Embryogenic Cell Suspension. Plant Cells Reports. 19:748-754.
PÉREZ PONCE et al.1998. Propagación y Mejora Genética de Plantas por Biotecnología. Capítulo 4, pp..57-79.
SHOOFS H. 1997. The Origin of Embryogenic Cells in Musa. Ph.D. Thesis, KULeuven, Belgium. 257p.
STROSSE H., DOMERGUE R., PANIS B., ESCALANT J.V. y COTE F. 2003. Suspensiones de Células Embriogénicas de Banano y Plátano. Guías técnicas INIBAP.
La capacidad de regeneración para el cultivar FHIA 21 por el método validado fue de 196 plántulas /mL de suspensión celular establecido. Una vez regeneradas las plántulas, se individualizaron y posteriormente se multiplicaron y se enraizaron en medios previamente establecidos por el laboratorio de micropropagación de plántulas- CORPOICA. Las plántulas enraizadas fueron endurecidas y adaptadas a condiciones de invernade- ro a una temperatura de 28ºC+/-2 con fotoperiodo natural y humedad relativa de 80%. El porcentaje de sobrevivencia fue de 95%.
THE Ralstonia solanacearum SPECIES COMPLEX: GENETIC DIVERSITY, PHYLOGENY AND MOLECULAR TYPING OF STRAINS WITH A PARTICULAR ATTENTION TO BACTERIAL WILTS OF BANANA KNOWN AS MOKO DISEASE, BUGTOK DISEASE AND BLOOD DISEASE, AND EMERGING
STRAINS
Phillipe. Prior1
E. Wicker2
M. Fegan3
SUMMARY
The genus Ralstonia is within the ß-subdivision of the Proteobacteria and includes five species, R. picketii, R. insidiosa, R. mannitolilytica, R. syzygii and R. solanacearum. R. solanacearum, a soilborne vascular pathogen of worldwide distribution, causes bacterial wilt of an unusually broad host range of plants (more than 200 species) from highly diverse botanical families including monocots and dicots (Hayward, 1964). This wide geographic distribution, large host range and the exceptional capacity of this organism to adapt to many different environments is mirrored in the astonishing phenotypic and genetic diversity at the strain level. Studies to characterize the genetic diversity of strains of R. solanacearum are needed to allow identification of infra-subspecific groups of strains that have common biological properties, evolutionary relationships or geographic origins. Such understanding may result in improving breeding strategies for obtaining durable resistance to bacterial wilt in many different plant species affected by this organism. A better knowledge of the genetic diversity of R. solanacearum is need to identify groups of R. solanacearum strains that are associated with pathogenicity for certain hosts, to rapidly stop or recognize quarantine organisms, and to develop targeted diagnostic tests. Bacterial wilt diseases of banana caused by members of the R. solanacearum species complex pose a major threat to the desert and cooking banana production (Sequeira 1998). Bacterial disease of banana and plantain can be divided into two groups; the soft rots caused by Erwinia sp. and the vascular infections primarily cause by R. solanacearum. A new vascular wilt disease of banana in Ethiopia and Uganda caused by a Xanthomonas campestis pv. musacearum, has also recently been described (Tushemereirwe et al., 2003). The bacterial wilts of banana known as Moko disease, Bugtok disease and Blood disease are caused by strains of R. solanacearum
or closely relatives. The symptoms of Moko disease and blood disease are very similar, leaves become yellow and flaccid and finally collapse. Fruits are destroyed and show internal vascular discolouration and infection is systemic. Both diseases are particularly common on ABB genotype bananas but all genotypes of banana are affected (Eden-Green and Seal, 1993; Thwaites et al., 2000). The very similar symptomatology of Blood disease and insect transmitted moko disease led Wardlaw (1972) to conclude that the two diseases are caused by the same organism, it is now acknowledged that the diseases are distinct (Thwaites et al., 2000). Bugtok disease varies in symptomatology from the other two diseases in that the symptoms are confined to the floral raceme of ABB (or BBB) genotype bananas and vascular discolouration rarely extends into the lower part of the stem (Thwaites et al., 2000).
The race and biovar classification systems are the international standard adopted to type R. solanacearum
strains. The races of R. solanacearum should more correctly be termed pathovars as they are named based upon the pathotype of the strain as the system is based on strain host range (Buddhenhagen et al., 1962) not susceptibility of host cultivars. Biovar typing is based on the metabolic profile of a given strain, especially the ability to metabolise disaccharides and hexose-alcohol (Hayward, 1964).
More recently, molecular based methods have resulted in a fine tuning of the understanding of the diversity of R. solanacearum strains. Cook et al. (1989) and Cook and Sequeira (1994) reported 46 multilocus genotypes
(
MLG) following RFLP analysis, these MLG groups clustered into two major branches: Division I made up of strains from race 1; biovars 3, 4 and 5 originating from the Old World (Asiaticum); and Division II including strains of race 1 and 2; and biovar 2 (race 3) originating from the New World (Americanum). Additional evidence for1CIRAD/INRA, UMR Peuplements Végétaux et Bioagresseurs en Milieu Tropical, Station de Ligne Paradis, 7 Chemin de l'IRAT, La Réunion, 97410,
Saint Pierre cedex , France.
2CIRAD-PRAM, BP 214, 97285, Le Lamentin cedex, Martinique (FWI)
revising the classification of R. solanacearum was provided by genetic fingerprinting analysis using AFLP and PCR-RFLP on the HRP gene cluster and nucleotide sequence analysis of 16S rRNA gene (Taghavi et al., 1996; Poussier et al., 2000a), the non coding but transcribed intergenic spacer (ITS) region between the 16S and 23S rRNA genes, and partial sequencing of the endoglucanase gene, the hrpB gene (Fegan et al., 1998; Poussier et al., 2000b) and the gene mutS, which encodes for a DNA mismatch repair protein. From the genetic fingerprinting and sequence analyses two other genetic groups of strains were identified which also correlate with geographical origin of the strains: a group of biovar 1 and 2 strains from Africa, and a group of strains from Indonesia. The group of strains from Indonesia, the most diverse genetic group, includes R. solanacearum strains belonging to biovars 1, 2 and 2T (isolated primarily from solanaceous plant species and cloves), but also two closely related organisms; R. syzigii, a pathogen from cloves, and the agent of Blood disease of banana (Taghavi et al., 1996). Thus, genetic diversity within the R. solanacearum species complex can be split into at least four phylogenetically different groups and two related species (Table 1).
Fegan and Prior (2005) made a proposal for a new and hierarchical classification scheme to describe intra- specific variations among strains of R. solanacearum. The overriding reason for this proposal was that the phenotypic (metabolic and pathogenic) measures of diversity are not consistent with genetic groupings. From the phylogenetic analysis that species complex can be subdivided into four monophyletic clusters of strains, termed phylotypes (Figure 1). Phylotype I includes strains belonging to Bv 3, 4, and 5, primarily originating from Asia. Phylotype II includes strains belonging to Bv 1, 2 and 2T, primarily originating from America. The Rs race 3 potato pathogen, which has a worldwide distribution, and the race 2 banana pathogen are both members of phylotype II. Phylotype III contains strains primarily isolated from Africa and surrounding islands, and belonging to to Bv 1 and 2T. Phylotype IV contains Rs strains isolated primarily from Indonesia belonging to Bv 1, 2 and 2T and also contains the Blood disease bacterium and R. syzygii. Each phylotype is composed of a number of groups of strains, with highly conserved endoglucanase and mutS gene sequences, termed sequevars. The phylotyping scheme is highly discriminatory, flexible, additive, and should allow a better prediction of the properties of strains.