Memoria para optar al Título Profesional de Ingeniero Agrónomo Mención: Fitotecnia / La salinidad en el suelo es un problema para la agricultura, que puede afectar el rendimiento y la calidad de los cultivos. El objetivo de este estudio fue comparar el efecto del estrés salino en parámetros agronómicos vegetativos y la actividad enzimática antioxidante de genotipos de un tomate “Cherry” cultivado (Solanum lycopersicum var. cerasiforme L.) y un tomate silvestre (Solanum chilense L.). El experimento se realizó en invernaderos de la Facultad de Ciencias Agronómicas de la Universidad de Chile, Santiago. El estrés salino se comenzó a aplicar a los 10 días del trasplante mediante la adición de diferentes concentraciones de NaCl a la solución nutritiva: 0 mM, 40 mM, 80 mM y 160 mM de NaCl, durante 40 días. Se establecieron 8 tratamientos con un diseño en bloques completos al azar y con un arreglo factorial 2x4, (2 genotipos y 4 concentraciones salinas), utilizando 5 repeticiones para cada tratamiento constituidas por 4 plantas. Se realizaron mediciones del peso seco y fresco, tasa media de crecimiento relativo (TCR) de la parte aérea, área foliar, número de hojas, longitud y diámetro del tallo, potencial hídrico foliar, xilemático y osmótico, contenido de agua y actividad enzimática. El peso fresco y seco de la parte aérea fue reducido por la salinidad. Además, se observó en ambos genotipos una disminución de la TCR, del área foliar, del número de hojas, de la longitud, y del diámetro del tallo en relación al tratamiento control. Tanto los potenciales (Ψw, Ψx y Ψs), como el contenido de agua de la planta disminuyeron con la salinidad, especialmente en la especie silvestre. Finalmente, se observó un aumento de la actividad específica de las enzimas presentes en las hojas del genotipo silvestre, lo que explicaría los mecanismos de detoxificación de radicales libres que utilizan estas plantas. En general ambos genotipos disminuyeron su crecimiento, sin embargo el genotipo nativo mostró mayor adaptación al déficit hídrico y tolerancia al estrés oxidativo causados por la salinidad. / Salinity is a problem for agriculture, which affect the yield and crop quality. The aim of this study was to compare the effect of salt stress on vegetative agronomic parameters and antioxidant activity of a cultivated Cherry tomato (Solanum lycopersicum var. cerasiforme L.) and a wild tomato (Solanum chilense L.) genotype. The experiment was conducted in greenhouses of the College of Agricultural Sciences of the University of Chile. Salt stress was applied 10 days after transplanting by adding different NaCl concentrations to the nutrient solution: 0 mM, 40 mM, 80 mM and 160 mM NaCl for 40 days. Eight treatments were set up with a randomized complete block design with a 2x4 factorial arrangement (2 genotypes and 4 salt concentrations), using 5 replicates for each treatment consisting of 4 plants each. Dry and fresh weight, shoot mean relative growth rate (RGR), leaf area, leaf number, stem length and diameter, water and osmotic potential, water content and enzymatic activity were measured. Fresh and dry weights of aerial parts were reduced by increasing salinity. It was also observed that relative to the control treatment, in both genotypes RGR, leaf area, leaf number, stem length and diameter decreased. Both, plant potential and water content decreased with increasing salinity, especially in the wild species. Finally, an increase in specific enzymes activity was observed in the leaves of the wild genotype, which may explain the free radicals detoxification mechanisms that these plants use. In general, both genotypes reduced their growth, but the native genotype showed better adaptation to water stress and tolerance to oxidative stress caused by salinity.

Memoria para optar al título de Ingeniero Agrónomo mención Fitotecnia / La salinidad en el suelo es un problema para la agricultura, que puede afectar el rendimiento y la calidad de los cultivos. El objetivo de este estudio fue comparar el efecto del estrés salino en parámetros agronómicos vegetativos y la actividad enzimática antioxidante de genotipos de un tomate “Cherry” cultivado (Solanum lycopersicum var. cerasiforme L.) y un tomate silvestre (Solanum chilense L.). El experimento se realizó en invernaderos de la Facultad de Ciencias Agronómicas de la Universidad de Chile, Santiago. El estrés salino se comenzó a aplicar a los 10 días del trasplante mediante la adición de diferentes concentraciones de NaCl a la solución nutritiva: 0 mM, 40 mM, 80 mM y 160 mM de NaCl, durante 40 días. Se establecieron 8 tratamientos con un diseño en bloques completos al azar y con un arreglo factorial 2x4, (2 genotipos y 4 concentraciones salinas), utilizando 5 repeticiones para cada tratamiento constituidas por 4 plantas. Se realizaron mediciones del peso seco y fresco, tasa media de crecimiento relativo (TCR) de la parte aérea, área foliar, número de hojas, longitud y diámetro del tallo, potencial hídrico foliar, xilemático y osmótico, contenido de agua y actividad enzimática. El peso fresco y seco de la parte aérea fue reducido por la salinidad. Además, se observó en ambos genotipos una disminución de la TCR, del área foliar, del número de hojas, de la longitud, y del diámetro del tallo en relación al tratamiento control. Tanto los potenciales (Ψw, Ψx y Ψs), como el contenido de agua de la planta disminuyeron con la salinidad, especialmente en la especie silvestre. Finalmente, se observó un aumento de la actividad específica de las enzimas presentes en las hojas del genotipo silvestre, lo que explicaría los mecanismos de detoxificación de radicales libres que utilizan estas plantas. En general ambos genotipos disminuyeron su crecimiento, sin embargo el genotipo nativo mostró mayor adaptación al déficit hídrico y tolerancia al estrés oxidativo causados por la salinidad.

Memoria para optar al título de Químico Farmacéutico / Esta memoria tuvo como objetivo evaluar la capacidad antioxidante de las partes aéreas de Quinchamalium chilense y las hojas de Adesmia boronioides, para contribuir al conocimiento farmacológico de estas especies autóctonas. Para esto se obtuvieron los extractos seriados con solventes de polaridad creciente: hexano, diclorometano y metanol. Siendo estudiado el extracto metanólico (EM) en este estudio por su mayor contenido de compuestos fenólicos, metabolitos secundarios con demostrada actividad antioxidante. Para evaluar la actividad antioxidante in vitro, se utilizaron distintos métodos como i) FRAP (poder reductor de Fe+3), ii) CUPRAC (poder reductor de Cu+2), iii) apagamiento del radical DPPH, iv) neutralización del radical anión superóxido (SO.) generado mediante el sistema xantina - xantina oxidasa y porcentaje de inhibición de la actividad de la xantina oxidasa (XO) de los EMs de ambas especies. En los ensayos FRAP y CUPRAC, los resultados fueron expresados como equivalentes Trolox/ g extracto seco. En el ensayo DPPH los resultados fueron expresados como la concentración efectiva cincuenta (CE50), tiempo efectivo cincuenta (TE50) y eficiencia antioxidante (EA), la sustancia de referencia fue Trolox. En el ensayo de Inhibición de Xo los resultados se expresaron como porcentaje de inhibición de la enzima, el compuesto de referencia fue alopurinol y en el de neutralización del radical anión superóxido se expresaron como porcentaje de disminución de este anión radical; en este caso el compuesto de referencia fue quercetina. Los resultados indican que el EM de Q. chilense (QM) presentó una mayor actividad antioxidante en todos los ensayos realizados respecto del EM de A. boronioides (ABM), éste último mostró actividad en todos los ensayos excepto en el método de apagamiento del radical DPPH / The aim of this report was to evaluate the antioxidant capacity of the aerial parts of Quinchamalium chilense and Adesmia boronioides leaves in order to contribute to the pharmacological knowledge of these native species. For this, serial extracts were obtained with increasing polarity solvents: hexane dichloromethane and metanol. Being studied the methanol extract by its higher content of phenolic compounds, secondary metabolites with proven antioxidant activity FRAP method of reducing power CUPRAC Fe +3 and +2 reducing power of Cu was used to evaluate the antioxidant activity in vitro, the results are expressed as Trolox / g dry matter equivalent. Furthermore scavening DPPH radical used observing a decrease in absorbance whose result is expressed as the effective concentration fifty (EC50) and effective time fifty (ET50) which allows for the antioxidant efficiency (AE) and its action against radical superoxide anion (SO.) system generated by xanthine - xanthine oxidase. Finally the percent inhibition exerted on the enzyme samples Xanthine oxidase (XO) was evaluate

Submitted by Marco Antônio de Ramos Chagas (mchagas@ufv.br) on 2017-05-10T17:38:43Z No. of bitstreams: 1 texto completo.pdf: 609213 bytes, checksum: 2d38b204162050215b755964519aea1f (MD5) / Made available in DSpace on 2017-05-10T17:38:43Z (GMT). No. of bitstreams: 1 texto completo.pdf: 609213 bytes, checksum: 2d38b204162050215b755964519aea1f (MD5) Previous issue date: 2002-01-31 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Plantas dos acessos de Lycopersicon peruvianum (LA 444/1-19, LA 371-20, PI 126444-3, PI 126928-2, PI 126944-6 e PI 126944-12) e de L. chilense (LA 130-5 e LA 2753-11) que possuem resistência de amplo espectro a tospovírus foram utilizadas no cruzamento com a cultivar Moneymaker (L. esculentum) para produção de híbridos interespecíficos, visando a introgressão dessa resistência no tomateiro cultivado. Para superar as barreiras interespecíficas verificadas nestes cruzamentos utilizou-se o cultivo in vitro de sementes imaturas em meio de cultura Murashige & Skoog (MS). Obtiveram-se cinco híbridos do cruzamento L. esculentum x LA 130-5, quatro do cruzamento L. esculentum x LA 2753-11, quatro do cruzamento L. esculentum x LA 371-20, cinco do cruzamento L. esculentum x LA 444/1-19, um do cruzamento L. esculentum x PI 126944-6 e um do cruzamento L. esculentum x PI 126944-12. Não se obteve nenhuma planta dos cruzamentos entre L. esculentum e os acessos PI 126444 e PI 126928, mesmo utilizando-se o cultivo in vitro de semente imatura. Todos os híbridos foram auto-incompatíveis e apresentaram características morfológicas intermediárias aos seus progenitores. A natureza híbrida das plantas F 1 foi confirmada utilizando-se um marcador molecular CAPS. Alguns dos híbridos foram propagados mediante o processo de estaquia e inoculados para avaliação da resistência com isolados de tospovírus, pertencentes às espécies Tomato spotted wilt virus - TSWV, Groundnut ringspot virus GRSV e Tomato chlorotic spot virus - TCSV. Os híbridos foram submetidos a duas inoculações via extrato foliar tamponado, realizadas num intervalo de sete dias. Apenas os híbridos do cruzamento L. esculentum x LA 371-20 e L. esculentum x PI 126944-6 foram resistentes aos três isolados utilizados. Os demais híbridos foram resistentes aos isolados das espécies GRSV e TCSV, mas suscetíveis ao isolado da espécie TSWV. Os híbridos foram retrocruzados com a cultivar Moneymaker para obtenção de populações de retrocruzamento (RC). Populações RC 1 para os híbridos L. esculentum x LA 130-5, L. esculentum x LA 2753-11, L. esculentum x LA 371-20 e L. esculentum x LA 444/1-19 foram obtidas utilizando-se também o cultivo in vitro de sementes imaturas, obtendo- se um total de 99 plantas RC 1 . Estas plantas foram autofecundadas e novamente retrocruzadas com a cultivar Moneymaker, gerando populações RC 1 F 2 e RC 2 , respectivamente. O estudo da herança da resistência em uma população RC 1 F 2 derivada de L. peruvianum LA 371-20 indicou que a resistência originária dessa fonte é condicionada por um gene dominante, sendo efetiva contra três espécies de tospovírus (TSWV, TCSV e GRSV). A análise genética dessa progênie com um marcador molecular CAPS ligado ao gene Sw-5 demonstrou que o gene de resistência derivado do acesso LA 371-20 é um alelo do loco Sw-5 ou um gene proximamente ligado. / Accessions of Lycopersicon peruvianum (LA 444/1-19, LA 371-20, PI 126444-3, PI 126928-2, PI 126944-6, PI 126944-12) and L. chilense (LA 130-5, LA 2753-11) that possess wide spectrum tospovirus resistance were used in crosses with the cultivar Moneymaker (L. esculentum) for production of interspecific hybrids, seeking the introgression of this resistance into cultivated varieties. The interspecific barriers in these crossings were overcome by cultivating immature seeds in Murashige & Skoog medium. Hybrids were obtained from crosses ́Moneymaker ́x LA 130-5; ́Moneymaker ́x LA 2753-11; ́Moneymaker ́x LA 371-20; ́Moneymaker ́ x LA 444/1-19; ́Moneymaker ́ x PI 126944-6 and ́Moneymaker ́ x PI 126944-12. Seeds derived from crosses between ́Moneymaker ́and accessions PI 126444 and PI 126928 did not germinated or produced abnormal seedlings. All hybrids were self-incompatible and displayed morphological characteristics intermediate to their progenitors. The hybrid nature of the F 1 plants was also confirmed by molecular marker analysis. Cuttings from some of the hybrids were inoculated with virus isolates, belonging to the species Tomato spotted wilt virus - TSWV, Groundnut ringspot virus - GRSV and Tomato chlorotic spot virus - TCSV. Only the cuttings from ́Moneymaker ́x LA 371-20 and ́Moneymaker ́x PI 126944-6 hybrids were resistant to all isolates. The others hybrids were resistant to GRSV and TCSV, but susceptible to the TSWV isolate. The hybrids were backcrossed to ́Moneymaker ́ for production of backcross populations (RC). RC 1 populations were obtained for ́Moneymaker ́ x LA 130-5, ́Moneymaker ́x LA 2753-11, ́Moneymaker ́ x LA 371-20 and ́Moneymaker ́ x LA 444/1-19. The RC 1 plants were selfed and again backcrossed to ́Moneymaker ́ to obtain RC 1 F 2 and RC 2 populations, respectively. Inheritance studies of the resistance in a population RC 1 F 2 derived from LA 371-20, showed that the resistance of this accession is conditioned by a dominant gene effective against three tospovirus species (TSWV, TCSV and GRSV). Genetic analysis of this progeny with a molecular CAPS marker linked to Sw-5, demonstrated that the gene derived from LA 371-20 is allelic to Sw-5 or a tightly linked gene. / Dissertação importada do Alexandria

Among viral diseases affecting cultivated tomato, Tomato yellow leaf curl disease (TYLCD) is one of the most devastating. This disease is caused by a complex of viruses of which Tomato yellow leaf curl virus (TYLCV) is regarded as the most important species. Current control strategies to fight viral diseases in tomato are mainly based on genetic resistance derived from wild relatives. In the present thesis, resistance derived from S. chilense and S. peruvianum has been exploited in breeding for resistance to TYLCD. In a previous study, TYLCV-resistant breeding lines derived from LA1932, LA1960 and LA1971 S. chilense accessions were developed. Therefore, the first objective of this thesis was to study the genetic control of the resistance derived from these accessions. With this aim, response to viral infection was assayed in segregating generations derived from the aforementioned resistant lines. The results obtained were compatible with a monogenic control of resistance. Resistance levels were higher in LA1960- and LA1971-derived F2 generations, as shown by slighter symptoms in the resistant plants and a higher number of asymptomatic plants compared with the results obtained in the LA1932-derived F2 generation. It is noteworthy that the level of resistance present in our materials is comparable to or even higher than the levels found in tomato lines homozygous for Ty-1. The response in plants heterozygous for the resistance gene was comparable to the response in homozygous plants for all three sources employed. This implies that the resistance genes derived from all three sources seem to be almost completely dominant. This effect was stronger for LA1971-derived resistance. The results were similar when comparing viral accumulation, as was expected, since a positive correlation was found in these families between viral accumulation and symptom scores. This has important implications in breeding, since the resistance will be used mostly for hybrid development. Our second objective was to map the loci associated with the major resistance genes identified. A total of 263 markers were screened, 94 of them being polymorphic between both species. Recombinant analysis allowed the resistance loci to be localized on chromosome 6, in a marker interval of 25 cM. This interval includes the Ty-1/Ty-3 region, where two S. chilense-derived TYLCD resistance loci were previously mapped. In order to test if the resistance genes identified in our populations were allelic to Ty-1 and Ty-3, further fine mapping was carried out. A total of 13 additional molecular markers distributed on chromosome 6 allowed 66 recombinants to be identified, and the resistance region to be shortened to a marker interval of approximately 950 kb, which overlaps with the Ty-1/Ty-3 region described previously by other authors. Therefore, the results obtained indicate that closely linked genes or alleles of the same gene govern TYLCV resistance in several S. chilense accessions. The third objective of the present thesis was to start the construction of a set of introgression lines (ILs) derived from Solanum peruvianum accession PI 126944 into the cultivated tomato genetic background. Once this collection of ILs is developed, it will represent a powerful tool for exploiting the resistance to different pathogens found in this particular accession in addition to other possible characters of interest. The starting plant material consisted of several segregating generations that were derived from two interspecific hybrids previously obtained by our group. Many crosses and embryo rescue were required to obtain subsequent generations due to the high sexual incompatibility that exists between tomato and PI 126944. Several mature fruits from the most advanced generations produced a few viable seeds, although embryo rescue was also employed to obtain progeny. As only a few plants were obtained by direct backcrossing, additional crosses were made in order to increase the number of descendants. A high degree of incompatibility was also found in crosses between sib plants. A total of 263 molecular markers were tested in some generations, 105 being polymorphic between tomato and PI 126944. Available generations were genotyped with these polymorphic markers in order to determine which alleles of S. peruvianum were already introgressed. On average, 79, 78 and 84 % of the S. peruvianum genome was represented in the pseudo-F2, pseudo-F4 and pseudo-F5 generations, respectively, for the markers analyzed. A reduction in the S. peruvianum genome was observed in more advanced generations, such as BC1 (56 %), pseudo-F2-BC1 (60 %) and pseudo-F3-BC1 (70 %). A greater reduction was observed in the pseudo-F3-BC2 generation (33 %). As a consequence of the reduction in the S. peruvianum genome, a loss of incompatibility was observed in some cases. The S. peruvianum genome was almost completely represented among the different plants of the most advanced generations. An evaluation for resistance to TYLCD and Tomato spotted wilt virus (TSWV) was carried out in some of the advanced generations, some of which were resistant to one or both viruses. In conclusion, we have conducted a successful and deeper exploitation of two wild species with proved resistance to TYLCD, S. chilense and S. peruvianum, identifying and fine mapping new genes of resistance. / Julián Rodríguez, O. (2014). Exploitation of Solanum chilense and Solanum peruvianum in tomato breeding for resistance to Tomato yellow leaf curl disease [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/36867 / TESIS

Se determinó la respuesta de resistencia de 10 patrones de tomate a una población avirulenta de Meloidogyne javanica en maceta. Los ensayos se realizaron en primavera, cuando las temperaturas permitían la expresión fenotípica de la resistencia del gen Mi-1 (28˚C), en verano sometidos a altas temperaturas y en campo, exponiéndolos a altas densidades poblacionales del nematodo. A temperaturas inferiores a 28˚C los patrones mostraron gran variabilidad en la respuesta de resistencia que osciló entre alta y moderadamente resistente (PG-76, Gladiator, MKT-410; Brigeor, 42851, 43965, Big Power y He-man), hasta susceptible (Beaufort, Maxifort). Por encima de 28˚C, sólo dos patrones (PG-76 y He-man) inhibieron la reproducción del nematodo. Frente a distintas poblaciones de M. arenaria, M. incognita y M. javanica, el patrón PG-76, fue altamente resistente a todas las poblaciones, Brigeor osciló entre altamente resistente y moderadamente resistente, mientras que Beaufort y Maxifort mostraron menor resistencia o fueron totalmente susceptibles; además ésta varió en función de la población analizada. Se caracterizó molecularmente el locus Mi-1 en los patrones híbridos y cultivares de tomate estudiados. Se emplearon los marcadores moleculares PM3, PMi y Mi23, específicos para la caracterización del locus Mi en patrones híbridos de tomate (S. lycopersicum × S. habrochaites; S. lycopersicum × S. chilense), mediante PCR. También se realizaron análisis bioinformáticos con marcadores específicos (Mint-up/do, C172, C2S4, IMO-F1/R1, y VIGS) para determinar la presencia del gen Mi-1.2 en dichos patrones. Los resultados mostraron que los marcadores PMi y Mi23 amplifican homólogos del gen Mi-1 en S. chilense, S. habrochaites y S. peruvianum y también en S. lycopersicum (marcador Mi23). El marcador PM3 amplificó el gen Mi-1.2 en Beaufort y Maxifort (S. lycopersicum × S. habrochaites) pero no fue efectivo para los híbridos de S. chilense. El marcador molecular PM3, no pudo determinar la expresión de del gen Mi-1.2 en Beaufort y Maxifort por hallarse fuera de la secuencia codificadora (CDS) del gen. Análisis bioinformáticos indicaron que ningún marcador específico diseñado para el gen Mi-1.2, podía este gen de otros homólogos presentes en S. lypcopersicum y S. peruvianum. El nuevo marcador Pau-Do en combinación con el primer C2S4, amplificaron un fragmento de 1.494 pb en la CDS del gen Mi-1.2 en raíces y hojas de Beaufort y Maxifort. La durabilidad de la resistencia del gen Mi-1 después del cultivo reiterado de patrones de tomate se determinó en ensayos de campo durante tres años consecutivos, empleando PG-76 y Brigeor. El patrón PG-76 fue muy resistente después del 1er ciclo de cultivo, pero mostró resistencia intermedia y suscetibilidad al finalizar el 2o y el 3er año de cultivo, respectivamente. El patrón Brigeor y el cultivar de tomate resistente Monika (control) mantuvieron un nivel de resistencia intermedio al final del 3er cultivo, aunque ensayos posteriores confirmaron la aparición de virulencia. Los resultados mostraron que el cultivo reiterado de patrones de tomate resistentes seleccionó rápidamente aislados virulentos de M. javanica. El fenotipo virulento de estas poblaciones se analizó molecularmente con el marcador MVC, diseñado para distinguir las poblaciones virulentas seleccionadas de Meloidogyne de los aislados naturalmente virulentos. Se analizaron dos poblaciones japonesas seleccionadas de M. incognita y M. javanica, tres poblaciones españolas virulentas seleccionadas, una población naturalmente virulenta y una avirulenta (todas M. javanica). Las muestras de ADN se obtuvieron de individuos juveniles o de hembras adultas y se incluyeron muestras de agua sin nematodos (5 µm filtrada) procedentes del drenaje de una maceta con una planta infectada por una población virulenta japonesa. El marcador MVC amplificó ADN en las muestras de agua pero no en las que sólo contenían ADN de nematodos. Las secuencias de ADN mostraron una estrecha correlación con diversas proteínas de especies de betaproteobacterias. Los experimentos revelaron que el marcador de MVC no está relacionado con un gen de virulencia del nematodo (avr) sino con betaproteobacterias. Finalmente, se estudió la existencia de homólogos del gen Mi en las especies de tomate silvestre Solanum chilense, S. habrochaites, S. peruvianum y S. huaylasense. La respuesta de resistencia de la variedad LA-1358 de S. huaylasense varió en función de la especie del nematodo estudiada: fue resistente frente a M. arenaria y susceptible frente a M. javanica. La reproducción de M. incognita fue muy variable y no difirió de la reproducción alcanzada en los dos cultivares empleados como controles. / The response of 10 Mi-1 tomato rootstocks to a Mi-avirulent population of M. javanica was determined in pot tests conducted in a greenhouse in spring when temperatures remained below the Mi-1 functionality resistance threshold (28 ˚C), and in summer when daily temperatures exceeded the Mi-1 expression threshold. Rootstocks were also evaluated in the field exposing them to high population densities of the nematode. Results on infectivity and reproduction below 28 ˚C indicated a wide variability in the resistance response of the rootstocks ranging from highly or intermediate resistance (PG-76, Gladiator, MKT-410; Brigeor, 42851, 43965, Big Power and He-man) to fully susceptible (Beaufort and Maxifort). At high temperature conditions, only PG-76 and He-man inhibited the reproduction of M. javanica. Rootstocks PG-76, Brigeor, Beaufort and Maxifort were challenged to different populations of M. arenaria, M. incognita and M. javanica. Rootstock PG-76 was highly resistant to all the populations tested, whereas the response of Brigeor ranged from highly to moderate resistance; the resistance response of rootstocks Beaufort and Maxifort varied according to the population tested. Molecular characterization of the resistance phenotype was performed for all the tomato hybrid rootstocks and cultivars tested. The markers PM3, PMi, Mi23, for the characterization of the Mi-locus of hybrid tomato rootstocks (S. lycopersicum × S. habrochaites and S. lycopersicum × S. chilense) were used for PCR reactions. In silico analyses were done with specific markers for the Mi-1.2 gene (Mint-up/do, C1/2, C2S4, IMO-F1/R1, and VIGS). Markers PMi and Mi23 were polymorphic for the Mi-1 locus in wild Solanum species (S. chilense, S. habrochaites, and S. peruvianum) and for S. lycopersicum (marker Mi23). Marker PM3 detected the Mi-1.2 gene in S. lycopersicum × S. habrochaites hybrid rootstocks, but not in the S. chilense hybrids. As marker PM3 is located outside the coding sequence of the Mi-1.2 gene, expression of this homolog could not be determined in Beaufort and Maxifort. In silico results indicated that none of the available markers for the Mi-1.2 gene could distinguish this homolog from the other Mi-homologs from S. lypcopersicum and S. peruvianum species. A new marker Pau-Do, in combination with C2S4, was designed to amplify in CDS of the Mi-1.2 gene. Amplification with these primers of cDNA from Beaufort and Maxifort indicated that the Mi-1.2 gene was expressed in both rootstocks, despite their susceptible phenotypic response to some Meloidogyne populations. The durability of the Mi-1 gene after repeated cultivation of resistant tomato rootstocks (PG-76 and Brigeor) was determined through field trials during three consecutive years. Rootstock PG-76 responded as highly resistant after the first cropping cycle, although it became fully susceptible after the second and the third cropping cycles. Rootstock Brigeor and the resistant tomato cultivar Monika (control), retained intermediate resistance levels at the end of the third year. Bioassays confirmed that selection of virulence occurred more rapidly in plots with rootstock PG-76 followed by Brigeor and the resistant tomato cultivar Monika. The virulent phenotype of the selected M. javanica populations in the field experiments was determined with MVC molecular marker, designed to distinguish selected from naturally virulent populations of Meloidogyne spp. The populations analyzed included two Japanese selected virulent populations, and the three virulent populations selected in the field trials, and one naturally virulent population and one avirulent population from Spanish. DNA samples were obtained from individual juveniles (J2) or adult females from all the selected virulent populations. Experiments included water samples free of nematodes (5-µm filtered), obtained from the draining-water of a plant infected by a Japanese selected virulent population. Amplification of DNA only occurred in samples of filtered water, but not in those containing only nematode genetic material. Sequencing and BLAST of the DNA fragments amplified by the MVC molecular marker, established a strong correlation of the amplified bands with proteins from betaproteobacteria species Overall, these results showed that the MVC marker is not related to a nematode virulence gene (avr) but to betaproteobacteria. New root-knot nematode resistant Mi-homologs were searched in accessions of the wild Solanum species. The S. huaylasense accession LA-1358 reduced reproduction of a population of M. arenaria to similar levels than the resistant tomato cultivar Anairis. Nevertheless, the resistance response of S. huaylasense accession LA-1358 was also nematode-species specific.

No description available.