Detección y caracterización de bacterias endofíticas en árboles de cafeto (Coffea arabica L.) y de sombra en Puerto Rico

dc.contributor.advisor Zapata-Serrano, Mildred Bolaños-Carriel, Carlos A. College of Agricultural Sciences en_US
dc.contributor.committee Estévez de Jensen, Consuelo
dc.contributor.committee Wessel Beaver, Linda
dc.contributor.department Department of Crops and Agro-Environmental Sciences en_US
dc.contributor.representative Alvarez, Jaquelina 2018-11-20T10:18:08Z 2018-11-20T10:18:08Z 2012
dc.description.abstract Among bacterial diseases affecting coffee (Coffea arabica L.), coffee leaf scorch (CLS) caused by the bacterium Xylella fastidiosa (Xf) Wells et al., limits production in many countries. The importance of endophytic bacteria is related to potential antagonistic or synergistic interactions with Xf. The objective of this research was to characterize bacterial endophytes of coffee and shade trees in Puerto Rico (PR). Three types of shade treatments were studied: coffee shaded with trees of high species diversity, coffee shaded with trees of low species diversity and sun coffee, in four localities in the dry and rainy seasons during years 2010-2012. In this study ANOVA in a complete randomized design was used to determine the effect of the factors. Endophytic bacteria were isolated on Periwinkle medium (semi selective to Xf) and characterized phenotypically. Endophytic Gram negative bacteria and tree samples with CLS disease symptons, were tested with a double antibody sandwich enzyme linked immune absorbent assay (DAS-ELISA for Xf). A subset of bacteria and tree samples suspected to have CLS and bacteria were analyzed with polymerase chain reaction (PCR) with Xf primers 272 -1-2, COX Xf and Xf-16S rRNA. Cluster analysis was carried out using Gower method for fastidious bacteria and spatial cluster analysis using SatScan for symptomatic trees. Few bacterial strains were of fastidious type. There were no significant differences in the percentage of fastidious bacteria, in the number of colony forming units (CFU/ml) and bacterial diversity per tree in symptomatic versus asymptomatic trees. CFU/ml and bacterial diversity per tree were higher in the rainy season compared to the dry season (α=0.05). The effects of location and shade treatment were more variable, with a tendency of lower diversity in sun versus shaded coffee. Spatial clustering showed more than 14 times greater relative risk of encountering diseased coffee trees at higher altitudes such as Adjuntas, Jayuya and Yauco (p<0.001). Some DNA products were amplified with PCR (272 - 1-2); but they were not related to Xf, neither with COX Xf primers. DNA sequencing was negative for Xf. Ambiguous results in DNA amplification and sequencing do not allow us to confirm that these samples are Xf. Therefore, the causal agent of the disease observed in PR remains to be identified according to Koch’s postulates. en_US
dc.description.graduationSemester Fall en_US
dc.description.graduationYear 2012 en_US
dc.description.sponsorship Proyecto ZTS-51 “Potential effects of Xylella fastidiosa on shade coffee establishment in Puerto Rico” del USDA. en_US
dc.language.iso es en_US
dc.rights.holder (C) 2012 Carlos A. Bolaños Carriel en_US
dc.rights.license All rights reserved en_US
dc.subject Enfermedades bacterianas en_US
dc.subject Coffea arabica L en_US
dc.title Detección y caracterización de bacterias endofíticas en árboles de cafeto (Coffea arabica L.) y de sombra en Puerto Rico en_US
dc.type Thesis en_US
dspace.entity.type Publication Crop Protection en_US M.S. en_US
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