Frequency and genetic variability of Fusarium oxysporum mating types

The genus Fusarium comprises a vast number of cosmopolitan species, many of which are important pathogens of crops of agronomic interest. Molecular analysis of mating type (MAT) genes is a useful tool to study reproductive lifestyles and relationships between species. The aim of the present research was to determine by PCR the type of MAT idiomorphs (MAT1-1 and/or MAT1-2) in Fusarium oxysporum, F. nygamai, F. thapsinum and F. verticillioides isolates obtained across 20 geographical regions of the central zone of Mexico, and to evaluate their sequence variability. PCR reactions from 110 isolates revealed that 66 Fusarium isolates presented the MAT1-1 idiomorph and 44 isolates presented the MAT1-2 idiomorph, but no isolate showed both idiomorphs. MAT1-1 and MAT1-2 idiomorph, from the same or different Fusarium species, coincided in the same field of several geographic regions. Selected sequences of the two idiomorphs showed greater divergence between species than within the same species. These changes were greater in the noncoding regions than in the coding regions. In general, these findings will help to better understand the genetic variability and, ideally, improve the management practices of crop diseases.El género Fusarium comprende una gran cantidad de especies cosmopolitas, muchas de las cuales son patógenos importantes de cultivos de interés agronómico. El análisis molecular de los genes del tipo de apareamiento (MAT) es una herramienta útil para estudiar los estilos de vida reproductivos y las relaciones entre especies. El objetivo de la presente investigación fue determinar el tipo de idiomorfos de MAT (MAT1-1 y/o MAT1-2) en aislados de Fusarium oxysporum, F. nygamai, F. thapsinum y F. verticillioides obtenidos de 20 sitios distribuidos en la zona central de México afectando cultivos de trigo y de garbanzo, y evaluar su variabilidad de secuencias. Las reacciones de PCR de 110 aislados revelaron que 66 presentaron el idiomorfo MAT1-1 y 44 presentaron el idiomorfo MAT1-2, pero ningún aislado mostró ambos idiomorfos. Los idiomorfos MAT1-1 y MAT1-2, de diferentes o de la misma especie de Fusarium, coincidieron en el mismo campo de cultivo de varios sitios. Las secuencias seleccionadas de los dos idiomorfos mostraron mayor divergencia entre especies que dentro de la misma especie. Estos cambios fueron mayores en las regiones no codificantes que en las regiones codificantes. La variación de los genes de tipo de apareamiento y la coexistencia de ambos idiomorfos en el mismo sitio agrícola, apuntan a un posible futuro cambio en la virulencia de los aislados de Fusarium. En general, estos hallazgos ayudarán a comprender mejor la variabilidad genética de algunas especies de Fusarium en México

Molecular based assessment of genetic diversity of xoconostle accessions (Opuntia spp.)

Xoconostle or acidic prickly pear is an important fruit in Mexico; it is produced by a group of Opuntia plants known for their nutritional qualities and adapted to harsh environmental conditions. In this study, we report for the first time the estimation of genetic diversity within a set of 24 xoconostle accessions using inter simple sequence repeats (ISSR) markers. Five ISSR primers were selected to detect DNA polymorphisms in these plants. Broad genetic diversity was detected (0.41-0.82, Dice coefficient) and the unweighted pair group method with the arithmetic averaging (UPGMA) analysis allowed discriminating all genotypes and enabled their clustering into six groups; the ‘Matizado’ accession was significantly divergent from all tested genotypes. In addition, as shown by the clustering analysis and principal component analysis (PCA), the tested genotypes did not group according to their origin, to culture conditions, or to the current species classification. This work, on one hand, demonstrates the high genetic variation among genotypes of xoconostles, and on the other hand, it suggests a taxonomic revision and raises doubts about the number of species reported for these plants.Keywords: Opuntia spp., acidic prickly pear, inter simple sequence repeats (ISSR) markers, taxonomyAfrican Journal of Biotechnology, Vol. 13(2), pp. 202-210, 8 January, 201

Assessment of genetic relationship in Persea spp by traditional molecular markers

Currently, the reclassification of the genus Persea is under discussion with molecular techniques for DNA analysis representing an alternative for inter- and intra-specific differentiation. In the present study, the traditional random-amplified polymorphic DNA (RAPD) and the inter simple sequence repeat (ISSR) markers were used to determine the genomic relationship of different species and hybrids representative of the subgenera Eriodaphne and Persea in a population conserved in a germplasm bank. The data were analyzed statistically using multivariate methods. In the RAPD analysis, a total of 190 polymorphic bands were produced, with an average of 23.7 bands per primer, the percentage contribution of each primer was from 7.66 to 19.63; the polymorphic information content (PIC) ranged from 0.23 to 0.45, with an average of 0.35. In the ISSR analysis, a total of 111 polymorphic bands were considered, with an average of 18.5 bands per primer, the percentage contribution of each was from 11.83 to 19.57; the PIC ranged from 0.35 to 0.48, with an average of 0.42. The phenograms obtained in each technique showed the relationship among the accessions through the clusters formed. In general, J.C. Reyes-Alemán et al. 2 Genetics and Molecular Research 15 (2): gmr.15027359 ©FUNPEC-RP www.funpecrp.com.br both the techniques grouped representatives of the Persea americana races (P. americana var. drymifolia, P. americana var. guatemalensis, and P. americana var. americana). However, it was not possible to separate the species of Persea used as reference into independent clades. In addition, they tended to separate the representatives of subgenera Eriodaphne and Persea

Morphological variability of native maize (Zea mays L.) of the west highland of Puebla and east highland of Tlaxcala, Mexico

The objective of this research was to assess the morphological variability of maize landraces native of the west highland of Puebla and east highland of Tlaxcala, México, in order to, besides define it, related it to races, commercial varieties and with the altitude of the localities of seed collection. The genetic resources evaluated were 134 accessions collected in 34 localities, along with 10 controls. Experiments were established on three localities using a Lattice 12 x 12. Thirty-two morphological traits were analyzed, 27 of them resulting with highly significant differences, reflecting the high variability at the level of morphological characters, many of them of agronomic interest. From variance analysis 16 traits were selected for use in a cluster analysis through the Modified Localization Method, which joint the populations in six groups, most of them in the group 1, with morphological traits of long cycle varieties: high plants, with greater primary branches of the tassel, greater ear diameter and length, and greater grain length and width. The conclusions indicate that the morphological variability of Landraces is not associated with the altitude of localities of seed collection and that these have more relation with Chalqueño race, small with Conico race, absent with Conico Norteño and Palomero Toluqueño races and almost absent with commercial varieties.The objective of this research was to assess the morphological variability of maize landraces native of the west highland of Puebla and east highland of Tlaxcala, México, in order to, besides define it, related it to races, commercial varieties and with the altitude of the localities of seed collection. The genetic resources evaluated were 134 accessions collected in 34 localities, along with 10 controls. Experiments were established on three localities using a Lattice 12 x 12. Thirty-two morphological traits were analyzed, 27 of them resulting with highly significant differences, reflecting the high variability at the level of morphological characters, many of them of agronomic interest. From variance analysis 16 traits were selected for use in a cluster analysis through the Modified Localization Method, which joint the populations in six groups, most of them in the group 1, with morphological traits of long cycle varieties: high plants, with greater primary branches of the tassel, greater ear diameter and length, and greater grain length and width. The conclusions indicate that the morphological variability of Landraces is not associated with the altitude of localities of seed collection and that these have more relation with Chalqueño race, small with Conico race, absent with Conico Norteño and Palomero Toluqueño races and almost absent with commercial varieties

Fruit size homologue gene variation in Mexican <em>Opuntia </em>sp.

351-356The Opuntia genus, an important horticultural crop in Mexico, is essentially a fruit crop. The fruits (“tunas” and “xoconostles”) exhibit a huge range of color and size but the genetic background of this diversity is little known. The aim of this research was to amplify a fruit size gene and to estimate the changes in the gene sequence in 91 genotypes of Mexican Opuntia. To accomplish this, the cleaved amplified polymorphic sequences (CAPS) technique was applied. A fragment of 850 bp was obtained using the primer pair Fruitfull-F131/Fruitfull-R1218 in all Opuntia genotypes studied here. There was no length variation observed among the undigested PCR products from the 91 accessions. The amplified PCR products (FRUITFULL-homologue gene) were digested with seven endonuclease enzymes. The enzymes HinfI and RsaI had no restriction site, while the enzymes AvaII and HhaI generated two monomorphic bands. However, the enzymes AluI, HaeIII and MboI produced several polymorphic fragments. The estimated Dice similarity coefficient ranged between 0.46 and 1.0. However, the most frequent estimated Dice similarity coefficient varied from 0.75 to 1.0. Indeed, 63 out of the 91 genotypes had the same genetic profile. The present results revealed that the FRUITFULL-homologue gene is conserved among Opuntia genotypes

Identificación molecular del complejo Botryosphaeria sp. asociado a cancros y secamiento de yemas en Eucalyptus sp.

Los problemas fitosanitarios afectan de manera drástica al cultivo o a la planta de eucalipto, por los daños que le producen. Botryosphaeria sp. está asociado a cancros y secamiento de yemas, muerte descendente, pudrición de frutos, pudrición del cuello y damping-off en plántulas, lo que es particularmente importante en las plantaciones comerciales de Eucalyptus para obtener madera en ciclos cortos. Con el objetivo de caracterizar e identificar a nivel molecular aislamientos de este hongo, en el trabajo que se describe a continuación se estimó, por un lado, la variabilidad genética en muestras enfermas con marcadores genómicos tipo ISSR, y por otro, se secuenció y comparó la región ITS. Los ISSR fueron analizados con técnicas multivariadas para agrupar a los aislamientos con base en su similitud genética, de lo que resultó que la mayoría de las muestras fueron muy similares entre sí, a nivel de genoma. Los resultados de la técnica de secuenciación de las regiones ITS indicaron la presencia de Neofusicoccum sp., Neofusicoccum parvum, Diplodia corticola, Lasiodiplodia pseudotheobromae, Neofusicoccum eucalyptorum y Neofusicoccum sp. En relación con los nucleótidos de la región secuenciada, la cantidad de polimorfismos entre los aislamientos estudiados y aquellos que se usaron como outgroups, obtenidos del GenBank, fue mínimo

Usefulness of three DNA-PCR techniques to differentiate Jalapeño pepper varieties

527-532The cultivation of pepper (Capsicum annuum) is one of the oldest in America. However, out of the 25 species described only 5 have been domesticated. The varieties registered and legally protected must comply with International Union for the Protection of New Varieties of Plants (UPOV) guidelines. Nevertheless, simple sequence repeat the morphological descriptors used for this purpose are sometimes subjective and they are altered by the environment conditions. Molecular genetic markers have been used as alternative to reduce these limitations. The aim of this study was to compare the effectiveness of three techniques based on PCR to discriminate varieties of jalapeño pepper with little phenotypic differences and with very similar shape of the fruit. The techniques used were random amplified polymorphic DNA-DNA amplification fingerprinting (RAPD-DAF), inter simple sequence repeat (ISSR) and simple sequen repeat (SSR) through capillary and conventional electrophoresis. Results indicated that the values of genetic variation in the studied jalapeno varieties are different depending on the technique used, which is due to the capacity of each technique to sample the genome

Variación de la región ribosómica nuclear en Crataegus L. del centro y sur de México.

This study was conducted at the Universidad Autónoma de Chapingo and concluded in October 2008, to determine the genetic relationships among species of Crataegus fromcentral and southern Mexico. The variation in the sequences of the nuclear ribosomal region was low in all accessions of germplasm of Mexican Crataegus, and the phylogramonly showed separation of the species used as positive controls, but did not show a clear separation of groups of species. However, all accessions had the same pattern of nucleotide substitution and very low values of the distanceof nucleotide composition; thus, Mexican Crataegus species have high genetic relationship among them, but there is alack of evidence to conclude that they are variants of the same taxonomic species. C. nelsoni and C. stipulosa could be a source of genes for C. mexicana because both species,from Chiapas, have the closest relationship with this species,which has the best agronomic characteristics.Este estudio fuerealizado en la Universidad Autónoma Chapingo y concluido en octubre de 2008 y tuvo como objetivo determinar las relaciones genéticas entre especies de Crataegus del centro y sur de México. La variación en las secuencias de la región ribosómica nuclear fue baja en todas las accesiones de germoplasma de Crataegus mexicanos, y el filograma sólomostró separación de las especies usadas como controles positivos, pero no mostró una clara separación de gruposde especies. Sin embargo, todas las accesiones tuvieron un mismo patrón de sustitución de nucleótidos y muy bajos valores en la distancia de composición de nucleótidos; porlo que las especie s mexicanas de Crataegus mostraron altarelación genética, pero falta evidencia para concluir que son variantes de una misma especie taxonómica. C nelsoni y C.stipulosa pueden ser una fuente de genes para C. mexicana porque ambas especies, originarias de Chiapas, tienen la másestrecha relación con esta especie , que es la que presenta las mejores características agronómicas