Browsing by Author "Quiroz, Karla"

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    Efficient protocols for the extraction of microbial DNA from the rhizosphere of hydrophilic forests in Chile
    (PONTIFICIA UNIV CATOLICA CHILE, FAC AGRONOMIA INGENIERIA FORESTAL, 2012) Caceres, Pablo; Cordero, Cecilia; Gonzalez, Gloria; Quiroz, Karla; Bobadilla, Juan C.; Bravo, Carmen; Caligari, Peter D. S.; Carrasco, Basilio; Garcia Gonzales, Rolando
    P. Caceres, C. Cordero, G. Gonzalez, K. Quiroz, J.C. Bobadilla, C. Bravo, P.D.S. Caligari, B. Carrasco, and R. Garcia-Gonzales. 2012. Efficient protocols for the extraction of microbial DNA from the rhizosphere of hydrophilic forests in Chile. Cien. Inv. Agr. 38(3): 585-592. A lysis buffer-based protocol (Protocol BA), a modified lysis buffer-based protocol (Protocol BA Mod) and a commercial extraction kit (Protocol PS Kit) (Power Soil, Mo bio Laboratories, CA USA) were each evaluated for their ability to produce high-quality DNA with yields sufficient to allow its use in biodiversity studies. Similarly, the effect of liquid nitrogen on the process of cell disruption in all of the protocols that were studied. DNA yields ranged from 12.4 ng g(-1) of processed soil to 9620 ng g(-1) using the modified lysis buffer and commercial extraction kit, respectively. The quality of the DNA was determined by the ability of the DNA to produce efficient and reproducible polymerase chain reaction (PCR) products, using primers for universal 16S and 18S ribosomal RNA regions from bacteria and fungi, respectively. High-quality DNA was obtained to run PCRs in all protocols, but the efficiency of the method depended on the dilution of the DNA prior to performing the PCR. The three extraction methods generated PCR products with 90% efficiency. The DNA produced with the commercial kit was able to produce the highest PCR efficiency (95%) when the 10(-1) dilution was used. The method based on the use of lysis buffer produced the highest efficiency (90%) using a 10(-2) dilution. Meanwhile, the modified lysis buffer-based protocol generated the highest efficiency of PCR products using the 10(-3) dilution factor with 95% of efficiency. For the first time, reliable and efficient DNA isolation from the rhizosphere of hydrolic forest is documented, enabling a wide range of applications for this technique.
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    Genetic diversity and population structure of Chilean blueberry Gaultheria pumila (L.f.) DJ Middleton (Ericaceae)
    (2020) Pico-Mendoza, Jose; Garcia-Gonzales, Rolando; Quiroz, Karla; Pinoargote, Miryan; Rodriguez-Alvarez, Yohaily; Chong, Borys; Caceres-Ruz, Pablo; Pino, Hugo; Caligari, Peter D. S.; Carrasco, Basilio
    Gaultheria pumila (L.f.) D.J. Middleton is a native shrub of Chile that produces edible berry fruits. This species is related to the cultivated Vaccinium species; for this reason it is currently called Chilean blueberry locally. Although G. pumila has important attributes, it has been largely ignored, and remains an unexplored genetic resource. This study investigates the genetic diversity to support the efforts to domesticate the species. Sampling was carried out in 11 sites collected from four Regions of Chile. In total, 160 individuals were collected and analyzed using a set of 10 simple sequence repeats (SSRs) markers. The average observed heterozygosity was Ho = 0.50, while the expected heterozygosity was He = 0.46. The fixation index (F-IS) showed an average of -0.07, and the proportion of differentiation among populations (F-ST) was 0.11. The average level of polymorphic loci in all populations (PPL) was 96.97%. AMOVA showed that the genetic diversity among populations was very low (Phi PT = 6%). Significant correlations were found between genetic and geographic distance. Multivariate and Bayesian analyses identified two genetic groups. These results will be very useful to support the efforts to domesticate and increase the value of this species.
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    In vitro culture of Luma chequen from vegetative buds
    (2013) Mancilla, Hector; Quiroz, Karla; Arencibia, Ariel; Carrasco, Basilio; Garcia-Gonzales, Rolando
    Luma chequen, a small tree or large shrub belonging to the Myrtaceae family, is endemic to South America and has medicinal, nutritional and ornamental potential. However, its native habitat is deteriorating gradually, and it is suffering from the effects of fragmentation that is being caused by the conversion of forest land to agricultural land and the natural expansion of monocultural plantations of exotic species, such as Pinus radiata. The purpose of this work is to develop an effective procedure for establishing in vitro cultures of the native Chilean species L. chequen. Aseptic nodal segments were evaluated after exposure to a disinfecting agent (1% solution of sodium hypochlorite) for different lengths of time. Murashige and Skoog (MS) or Woody Plant (WPM) culture media with 6-Bencilaminopurine (BAP) or 2-isopentenil adenine (2-iP) added to a concentration of 1 mg L-1 were evaluated. Although no significant differences were observed between cultures with and without additives, 40.43% of the explant cultures were successfully established. Furthermore, the choice of basal medium or the addition of plant growth regulators was not found to affect the shoot formation efficiency.
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    IN VITRO PROPAGATION OF CEDAR (Cedrela odorata L.) FROM JUVENILE SHOOTS
    (2011) Garcia-Gonzales, Rolando; Delgado, Miladys; Gonzalez, Yailin; Gonzalez, Anibal; Garriga, Miguel; Caligari, Peter D. S.; Carrasco, Basilio; Quiroz, Karla
    Cedrela odorata L. is one of the most important timber species currently traded in the Caribbean and Central America; however, it has been intensively exploited. In vitro techniques and clonal propagation can help to develop new plantations and assist in establishing improvement programs for this species. The aim of this study was to develop a protocol to establish in vitro conditions and to micropropagate this species from nodal explants from juvenile cuttings taken from field trees. Disinfection of node explants with 5% propiconazole CE 25 during 3 min resulted in 100% explant disinfection and 60% morphogenic response on those established explants. Shoot development was optimized by cultivating in vitro node explants in Murashige and Skoog basal medium supplemented with 2 mg L-1 6-bencilaminopurine and 3 mg L-1 naphthaleneacetic acid. This medium resulted in 100% shoot development from the in vitro node explants with a 3.93 cm mean height. Rooting was also stimulated 6 wk after individualization of the regenerated plants on the same micropropagation medium with a mean of 3.9 roots per plant. In vitro plants did not show morphologic differences when compared to ex vitro seeds.
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    In vitro culture of Luma chequen from vegetative buds = Establecimiento al cultivo in vitro de Luma chequen a partir de segmentos nodales.
    (2013) Mancilla Chávez, Héctor Eduardo; Quiroz, Karla; Arencibia, Ariel; Carrasco Gálvez, Basilio Alejandro; García-Gonzáles, Rolando
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    MOLECULAR TOOLS FOR RAPID AND ACCURATE DETECTION OF BLACK TRUFFLE (Tuber melanosporum Vitt.) IN INOCULATED NURSERY PLANTS AND COMMERCIAL PLANTATIONS IN CHILE
    (2011) Cordero, Cecilia; Caceres, Pablo; Gonzalez, Gloria; Quiroz, Karla; Bravo, Carmen; Ramirez, Ricardo; Caligari, Peter D. S.; Carrasco, Basilio; Garcia-Gonzales, Rolando
    Truffle (Tuber melanosporum Vitt.) culture is an agroforestry sector in Chile of increasing interest due to the high prices that truffles fetch in the national market and the recent evidence that its commercial production is possible in Chilean climatic and soil conditions. In this study, the efficiency of three methods of DNA extraction from a mix of 5 g of soil and roots from both nursery and field plants of Quercus ilex L. mycorrhized with T. melanosporum were evaluated, and a simple and reproducible protocol was established. Detection of T. melanosporum was performed by the technique of cleaved amplified polymorphic sequence (CAPS) from amplicons generated with the primers ADL1 (5'-GTAACGATAAAGGCCATCTATAGG-3') and ADL3 (5'-CGTTTTTCCTGAACTCTTCATCAC-3'), where a restriction fragment of 160 bp specific for T. melanosporum was generated, which allows the discrimination of this species from the rest of the species belonging to the Tuber sp. genus. Direct detection of T. melanosporum in one step was also obtained by polymerase chain reaction (PCR) from total DNA isolated from mycorrhized roots and with the primers ITSML (5'-TGGCCATGTGTCAGATTTAGTA-3') and ITSLNG (5'-TGATATGCTTAAGTTCAGCGGG-3'), generating a single amplicon of 440 bp. The molecular detection of T. melanosporum by the methods presented here will allow the rapid and accurate detection of mycorrhization of trees, both under nursery and field conditions. This technology will also provide more security to farmers by controlling the quality of the mycorrhized trees they will plant and also by following the mycorrhization status of established orchards.
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    Regeneration of highland papaya (vasconcellea pubescens) from anther culture
    (2018) Chong Pérez, Borys; Carrasco Gálvez, Basilio Alejandro; Silva, Herman; Herrera, Francisca; Quiroz, Karla; Garcia Gonzales, Rolando