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Banguela A.,Institute Investigaciones en Fruticultura Tropical IIFT | Rodriguez R.,Institute Investigaciones en Fruticultura Tropical IIFT
Journal of Biotechnology | Year: 2011

Bacterial levansucrase (EC 2.4.1.10) converts sucrose into non-linear levan consisting of long β(2,6)-linked fructosyl chains with β(2,1) branches. Bacterial levan has wide food and non-food applications, but its production in industrial reactors is costly and low yielding. Here, we report the constitutive expression of Gluconacetobacter diazotrophicus levansucrase (LsdA) fused to the vacuolar targeting pre-pro-peptide of onion sucrose:sucrose 1-fructosyltransferase (1-SST) in tobacco, a crop that does not naturally produce fructans. In the transgenic plants, levan with degree of polymerization above 104 fructosyl units was detected in leaves, stem, root, and flowers, but not in seeds. High levan accumulation in leaves led to gradual phenotypic alterations that increased with plant age through the flowering stage. In the transgenic lines, the fructan content in mature leaves varied from 10 to 70% of total dry weight. No oligofructans were stored in the plant organs, although the in vitro reaction of transgenic LsdA with sucrose yielded β(2,1)-linked FOS and levan. Transgenic lines with levan representing up to 30mgg-1 of fresh leaf weight produced viable seeds and the polymer accumulation remained stable in the tested T1 and T2 progenies. The lsdA-expressing tobacco represents an alternative source of highly polymerized levan. © 2011 Elsevier B.V. Source


Banguela-Castillo A.,Institute Investigaciones en Fruticultura Tropical IIFT | Ramos-Gonzalez P.L.,Institute Investigaciones en Fruticultura Tropical IIFT | Pena-Marey M.,Institute Investigaciones en Fruticultura Tropical IIFT | Tanaka F.A.O.,University of Sao Paulo | And 3 more authors.
Crop Protection | Year: 2015

Muscodor is an endophytic fungal genus whose members produce volatile organic compounds (VOCs) with broad antimicrobial, nematocidal and insecticidal activities. This study describes the isolation and characterization of a new strain of Muscodor albus, designated as M. albus aa3, from wild pineapple (Ananas ananassoides) plants collected in Havana, Cuba. In vitro cultures of M. albus aa3 on both potato dextrose agar media (PDA) and paddy produced VOCs with antimicrobial activity against Escherichia coli and plant pathogens, including several species of the Phytophthora genus and the wood rot fungus Fomitiporia maxonii; but innocuous to the beneficial mycopathogen Trichoderma koningii. GC/MS analysis indicated the unique composition of the mixture of VOCs emitted by aa3, in which sesquiterpenes represent the most abundant compounds. VOCs emitted during the growth of M. albus aa3 on paddy grains protected Persian lime (Citrus×. latifolia Tanaka) fruits from infection by Phytophthora nicotianae Breda de Haan, suggesting the potential use of this fungus for postharvest biofumigation. Isolation of M. albus from wild pineapple points out this plant as a susceptible host to be colonized by distinct species of the Muscodor genus. © 2015. Source


Rodriguez-Medina N.N.,Institute Investigaciones en Fruticultura Tropical IIFT | Fermin G.A.,University of Los Andes, Venezuela | Valdes-Infante J.,Institute Investigaciones en Fruticultura Tropical IIFT | Velasquez B.,Institute Investigaciones en Fruticultura Tropical IIFT | And 4 more authors.
Acta Horticulturae | Year: 2010

Usually, the easiest assessment of genetic variation is through morphological or phenotypic measures. Also, the problems arising from the identification of a great number of plants in a fruit tree collection as well as those concerned with the protection of varietal names ask for the use of specific descriptors. In consequence, the guidelines published in 1987 by the International Union for the Protection of New Varieties of Plants (UPOV) provided the strategy for the conduction of tests for distinctness, homogeneity, and stability in guava. These descriptors are an important means for the standardization of guava characterization worldwide and provide an easy and rapid way to discriminate between guava phenotypes. The descriptors generally include highly heritable traits that can be easily detected visually. In addition, they may include a limited number of additional characters desirable by user consensus. The current study offers more than 50 descriptors, many of them accompanied by illustrations to help the selection of different variable states. The number of variables recommended for grouping accessions and the evaluated characters was increased in relation to the ones listed in the UPOV guidelines. Classes of quantitative traits were established to permit the evaluation of these characters for both quantitative and qualitative data. Values from 1 to 9 were used to design different states of each descriptor, thus allowing the establishment of an electronic database and data processing. A minimum of highly discriminative descriptors was identified. Source


Valdes-Infante J.,Institute Investigaciones en Fruticultura Tropical IIFT | Rodriguez-Medina N.N.,Institute Investigaciones en Fruticultura Tropical IIFT | Velasquez B.,Institute Investigaciones en Fruticultura Tropical IIFT | Rivero D.,Institute Investigaciones en Fruticultura Tropical IIFT | And 6 more authors.
Acta Horticulturae | Year: 2010

Agro-morphologic traits and molecular markers were compared in terms of their polymorphism level, discriminating power, and informativeness for 23 genotypes assembled in the Cuban guava germplasm collection. AFLP and SSR markers were powerful techniques for guava discrimination and variety identification, but the high level of polymorphic loci detected by the dominant AFLP marker highlights the discriminating capacity of this genetic marker. With a single AFLP primer combination all of the individuals were identified, while only a few genotypes can be differentiated with a single SSR primer combination or by morphological variables. The higher values of expected heterozygosity were detected by SSR. This value doubled the one obtained with AFLP, and reflects the high level of informativeness of this marker, due to the multiallelic and co-dominant nature of SSR; which makes them suitable for diversity studies. The morphologic diversity index provided a good estimate of diversity among guava accessions when phenotypic traits of high heritability were used, and it was comparable with the expected heterozygosity scored with DNA markers. The value of this index was the lowest. The assay efficiency index (Ai) and marker index (MI) had the same pattern of variation than discrimination capacity (D), number of banding pattern (I), number of unique banding pattern (Iu) and number of effective pattern (P) for both molecular markers. Then, these indexes are probably indicators of the discriminating capacity in guava. Source


Rodriguez-Medina N.N.,Institute Investigaciones en Fruticultura Tropical IIFT | Valdes-Infante J.,Institute Investigaciones en Fruticultura Tropical IIFT | Velasquez B.,Institute Investigaciones en Fruticultura Tropical IIFT | Rivero D.,Institute Investigaciones en Fruticultura Tropical IIFT | And 6 more authors.
Acta Horticulturae | Year: 2010

Guava (Psidium guajava L.) belongs to the Myrtaceae family and is native to the tropical and subtropical regions of America. It produces a fruit of high nutritional value due to its mineral and vitamin content. During the past 2 decades, classical methods to evaluate genetic variation have been complemented by molecular DNA techniques. There is a great potential for the application of these molecular markers to fruit crops. The objective of this research was to compare results derived from individual versus combined data sets for varietal identification and diversity estimation in guava germplasm by different DNA markers. AFLP data permitted the discrimination of all the accessions evaluated, but diversity groups were not observed. Microsatellite (SSR) markers detected seven diversity groups, although all the accessions could not be differentiated. The combined AFLP and SSR data offered similar results only when AFLP markers were used. Although coincidences were identified in individuals and combined dendrograms, the integration of the information derived by each marker system individually permitted a more accurate estimation of guava germplasm diversity. This corroborates the strengths and constraints of each data set. Thus, the congruence or correspondence among the results derived from individual data sets is the most important point to consider before combining different types of data. Source

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