Effect of the Hope FT-B1 Allele on wheat heading time and yield components

Precise regulation of flowering time is critical for plant reproductive success and, in cereals, to maximize grain yields. Seasonal cues including temperature and day length are integrated to regulate the timing of flowering. In temperate cereals, extended periods of cold (vernalization) release the repression of FLOWERING LOCUS T1 (FT1), which is upregulated in the leaves in response to inductive long-day photoperiods. FT1 is a homolog of rice HD3a, which encodes a protein transported from leaves to the shoot apical meristem to induce flowering. A rare FT-B1 allele from the wheat variety “Hope” has been previously shown to be associated with an early flowering phenotype under long-day photoperiods. Here, we demonstrate that the Hope FT-B1 allele accelerates flowering even under short days, and that it is epistatic to the VERNALIZATION 1 (VRN1) gene. On average, the introgression of Hope FT-B1 into 6 genetic backgrounds resulted in 2.6 days acceleration of flowering (P < 0.0001) and 4.1% increase in spike weight (P = 0.0093), although in one variety, it was associated with a decrease in spike weight. These results suggest that the Hope FT-B1 allele could be useful in wheat breeding programs to subtly accelerate floral development and increase adaptation to changing environments.Fil: Nitcher, Rebecca. University of California. Department of Plant Sciences; Estados UnidosFil: Pearce, Stephen. University of California. Department of Plant Sciences; Estados UnidosFil: Tranquilli, Gabriela. University of California. Department of Plant Sciences; Estados Unidos. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Xiaoqin, Zhang. University of California. Department of Plant Sciences; Estados UnidosFil: Dubcovsky, Jorge. University of California. Department of Plant Sciences; Estados Unidos. Howard Hughes Medical Institute; Estados Unido

Genetic and physical mapping of the earliness perse locus Eps - Am1 in Triticum monococcum identifies early flowering 3 (ELF3) as a candidate gene

Wheat cultivars exposed to optimal photoperiod and vernalization treatments still exhibit differences in heading time. This variation, known as earliness per se (Eps), is important for the fine-tuning of flowering and the adaptation to different environments. We previously identified the Eps-Am1 locus from Triticum monococcum and showed that the allele from cultivated accession DV92 significantly delays flowering and increases the number of spikelets per spike relative to the allele from wild accession G3116. We expanded a high-density genetic map and physical map of the Eps-Am1 region and identified the wheat ortholog of circadian clock regulator EARLY FLOWERING 3 (ELF3) as one of the candidate genes. No differences were found in ELF3 transcript levels between NILs carrying the DV92 and G3116 Eps-Am1 alleles, but the encoded ELF3 proteins differed in four amino acids. These differences were associated with altered transcription profiles of PIF-like, PPD1 and FT1, which are known downstream targets of ELF3. Tetraploid wheat lines with combined truncation mutations in the A- and B-genome copies of ELF3 flowered earlier and had less spikelets per spike than the wild type control under SD and LD conditions. Both effects were stronger in the photoperiod sensitive than the photoperiod insensitive background, indicating an epistatic interaction between PPD1 and ELF3. By contrast, the introgression of the T. monococcum chromosome segment carrying Eps-Am1-l allele from DV92 into durum wheat delayed flowering and increased the number of spikelets per spike in the field, providing a novel allele to modulate flowering time and spike development in wheat.Inst. de Recursos BiológicosFil: Alvarez, María Alejandra. University of California. Department of Plant Sciences; Estados UnidosFil: Tranquilli, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Lewis, Silvina. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Kippes, Nestor. University of California. Department of Plant Sciences; Estados UnidosFil: Dubcovsky, Jorge. University of California. Department of Plant Sciences; Estados Unidos. Howard Hughes Medical Institute; Estados Unido

Wheat lines, suffering structural rearrangements between wheat-1BS and rye-1RS chromosomes, display differential patterns of magnesium accumulation

Poster no. 238Two near isogenic lines, designated as 1RS and 1RW, resulting from the recombination of the rye (Secale cereale) chromosome 1RS with chromosome 1BS of bread wheat (Triticum aestivum), differ in a relatively small region of that short chromosome arm. We have recently reported that chromosome rearrangements in this region imply modifications in the dosage of some genes (including OPRIII codifying an enzyme involved in jasmonic acid (JA) biosynthesis pathway). This dosage difference confer differential drought resistance in a way primarily associated to the capacity of roots for soil exploration. An emerging question is whether or not those rearrangements also differentially influence plant mineral nutrition. In the present study we analyzed the ionome of 1RS and 1RW, which unveiled the existence of relevant differences in the distribution of magnesium (Mg) between the shoot and the root of these lines. Following this observation, we explored the physiological and molecular determinants of differential magnesium accumulation observed.Instituto de Recursos BiológicosFil: Gualano, L.D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Moriconi, Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Tranquilli, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Santa-María, Guillermo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; Argentin

Physiological and genetic characterization of wheat lines sharply differing in sodium accumulation

Poster no. 129Improving nutrient use efficiency is an important objective in modern breeding programs. Our group attempts to elucidate the components that contribute to greater efficiencies of potassium (K) acquisition and utilization in wheat (Triticum aestivum), and its nexus with sodium (Na) dynamics.Instituto de Recursos BiológicosFil: Silva, Martha M. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Moriconi, Jorge. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Gualano, L.D. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; ArgentinaFil: Tranquilli, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Santa-María, Guillermo E. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto Tecnológico Chascomús; Argentina. Universidad Nacional de San Martín; Argentin

Wheat plant height locus RHT25 encodes a PLATZ transcription factor that interacts with DELLA (RHT1)

Plant height is an important agronomic trait with a significant impact on grain yield, as demonstrated by the positive effect of the REDUCED HEIGHT (RHT) dwarfing alleles (Rht1b) on lodging and harvest index in the “Green Revolution” wheat vari eties. However, these gibberellic acid (GA)-insensitive alleles also reduce coleoptile length, biomass production, and yield potential in some environments, triggering the search for alternative GA-sensitive dwarfing genes. Here we report the identification, validation, and characterization of the gene underlying the GA-sensitive dwarfing locus RHT25 in wheat. This gene, designated as PLATZ-A1 (TraesCS6A02G156600), is expressed mainly in the elongating stem and developing spike and encodes a plant-specific AT-rich sequence- and zinc-binding protein (PLATZ). Natural and induced loss-of-function mutations in PLATZ-A1 reduce plant height and its over expression increases plant height, demonstrating that PLATZ-A1 is the causative gene of RHT25. PLATZ-A1 and RHT1 show a significant genetic interaction on plant height, and their encoded proteins interact with each other in yeast and wheat protoplasts. These results suggest that PLATZ1 can modulate the effect of DELLA on wheat plant height. We identified four natural truncation mutations and one promoter insertion in PLATZ-A1 that are more frequent in modern varieties than in landraces, suggesting positive selection during wheat breeding. These mutations can be used to fine-tune wheat plant height and, in combination with other GA-sensitive dwarfing genes, to replace the GA-insensitive Rht1b alleles and search for grain yield improvements beyond those of the Green Revolution varieties.Fil: Zhang, Junli. University of California. Department of Plant Sciences; Estados UnidosFil: Li, Chengxia. University of California. Department of Plant Sciences; Estados UnidosFil: Zhang, Wenjun. University of California. Department of Plant Sciences; Estados UnidosFil: Zhang, Xiaoqin. University of California. Department of Plant Sciences; Estados UnidosFil: Mo, Youngjun. University of California. Department of Plant Sciences; Estados UnidosFil: Tranquilli, Gabriela E. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Vanzetti, Leonardo Sebastian. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez. Grupo Biotecnología y Recursos Genéticos; ArgentinaFil: Dubcovsky, Jorge. University of California. Department of Plant Sciences; Estados Unidos. Howard Hughes Medical Institute; Estados Unido

Criterios de selección fenotípica en el mejoramiento vegetal: mirando debajo de la alfombra

Poster¿En qué punto nos encontramos? Creciente demanda mundial de alimentos. Necesidad de aumentar la productividad de los cultivos en forma sustentable. Contraste con los objetivos de la revolución verde del siglo XX: aumento de rendimientos sobre la base del mejoramiento genético vegetal y utilización masiva de agroquímicos. Desaceleración de la tasa de incremento de potencial productivo de los principales cereales por la vía del mejoramiento.Fil: Di Salvo, Luciana P. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Tranquilli, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: García de Salamone, Ines E. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos. Cátedra de Microbiología Agrícola; Argentin

Characterization of the repetitive DNA landscape in wheat homeologous group 4 chromosomes

Background: The number and complexity of repetitive elements varies between species, being in general most represented in those with larger genomes. Combining the flow-sorted chromosome arms approach to genome analysis with second generation DNA sequencing technologies provides a unique opportunity to study the repetitive portion of each chromosome, enabling comparisons among them. Additionally, different sequencing approaches may produce different depth of insight to repeatome content and structure. In this work we analyze and characterize the repetitive sequences of Triticum aestivum cv. Chinese Spring homeologous group 4 chromosome arms, obtained through Roche 454 and Illumina sequencing technologies, hereinafter marked by subscripts 454 and I, respectively. Repetitive sequences were identified with the RepeatMasker software using the interspersed repeat database mips-REdat_v9.0p. The input sequences consisted of our 4DS454 and 4DL454 scaffolds and 4ASI, 4ALI, 4BSI, 4BLI, 4DSI and 4DLI contigs, downloaded from the International Wheat Genome Sequencing Consortium (IWGSC). Results: Repetitive sequences content varied from 55% to 63% for all chromosome arm assemblies except for 4DLI, in which the repeat content was 38%. Transposable elements, small RNA, satellites, simple repeats and low complexity sequences were analyzed. SSR frequency was found one per 24 to 27 kb for all chromosome assemblies except 4DLI, where it was three times higher. Dinucleotides and trinucleotides were the most abundant SSR repeat units. (GA)n/(TC)n was the most abundant SSR except for 4DLI where the most frequently identified SSR was (CCG/CGG)n. Retrotransposons followed by DNA transposons were the most highly represented sequence repeats, mainly composed of CACTA/En-Spm and Gypsy superfamilies, respectively. This whole chromosome sequence analysis allowed identification of three new LTR retrotransposon families belonging to the Copia superfamily, one belonging to the Gypsy superfamily and two TRIM retrotransposon families. Their physical distribution in wheat genome was analyzed by fluorescent in situ hybridization (FISH) and one of them, the Carmen retrotransposon, was found specific for centromeric regions of all wheat chromosomes. Conclusion: The presented work is the first deep report of wheat repetitive sequences analyzed at the chromosome arm level, revealing the first insight into the repeatome of T. aestivum chromosomes of homeologous group 4.Fil: Garbus, Ingrid. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Bahia Blanca. Centro Recursos Naturales Renovables de Zona Semiarida(i); ArgentinaFil: Romero, José Rodolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Bahia Blanca. Centro Recursos Naturales Renovables de Zona Semiarida(i); ArgentinaFil: Miroslav, Valarik. Centre of the Region Haná for Biotechnological and Agricultural Research. Institute of Experimental Botany; República ChecaFil: Vanzurova, Hana. Centre of the Region Haná for Biotechnological and Agricultural Research. Institute of Experimental Botany; República ChecaFil: Karafiatova, Miroslava. Centre of the Region Haná for Biotechnological and Agricultural Research. Institute of Experimental Botany; República ChecaFil: Caccamo, Mario. Norwich Research Park. Genome Analysis Centre; Reino UnidoFil: Dolezel, Jaroslav. Centre of the Region Haná for Biotechnological and Agricultural Research. Institute of Experimental Botany; República ChecaFil: Tranquilli, Gabriela. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto Recursos Biológicos; ArgentinaFil: Helguera, Marcelo. Instituto Nacional de Tecnología Agropecuaria (INTA). Estación Experimental Agropecuaria Marcos Juárez; ArgentinaFil: Echenique, Carmen Viviana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Conicet - Bahia Blanca. Centro Recursos Naturales Renovables de Zona Semiarida(i); Argentin

Integración de herramientas informáticas para el diseño de marcadores moleculares ligados a un gen de interés a partir de un microarray de genotipado de trigo pan

El acceso a nuevas tecnologías moleculares para su aplicación en el mejoramiento de los cultivos demanda la utilización de herramientas informáticas de manera integrada para el tratamiento de los datos. Se presenta la confección de un mapa genético integrando 3232 SNP (en inglés, Single Nucleotide Polymorphism) obtenidos a partir de un microarray de SNP dise˜nado para trigo pan (Triticum aestivum) y 212 SSR (en inglés, Simple Sequence Repeat), utilizados previamente en el mapeo de una región cromosómica asociada a la resistencia de la Fusariosis de la Espiga de Trigo (FET), utilizando MapMerger y la librería RQTL. Se seleccionaron 15 SNP candidatos sobre los cuales se diseñaron cebadores in silico, para convertirlos en marcadores KASP (en ingles, Kompetitive allele-specific PCR), utilizando PolyMarker. Se espera contribuir con el desarrollo de un nuevo marcador asociado a un gen de resistencia a FET que pueda transferirse a la comunidad de mejoradores.Sociedad Argentina de Informática e Investigación Operativ

Integración de herramientas informáticas para el diseño de marcadores moleculares ligados a un gen de interés a partir de un microarray de genotipado de trigo pan

El acceso a nuevas tecnologías moleculares para su aplicación en el mejoramiento de los cultivos demanda la utilización de herramientas informáticas de manera integrada para el tratamiento de los datos. Se presenta la confección de un mapa genético integrando 3232 SNP (en inglés, Single Nucleotide Polymorphism) obtenidos a partir de un microarray de SNP dise˜nado para trigo pan (Triticum aestivum) y 212 SSR (en inglés, Simple Sequence Repeat), utilizados previamente en el mapeo de una región cromosómica asociada a la resistencia de la Fusariosis de la Espiga de Trigo (FET), utilizando MapMerger y la librería RQTL. Se seleccionaron 15 SNP candidatos sobre los cuales se diseñaron cebadores in silico, para convertirlos en marcadores KASP (en ingles, Kompetitive allele-specific PCR), utilizando PolyMarker. Se espera contribuir con el desarrollo de un nuevo marcador asociado a un gen de resistencia a FET que pueda transferirse a la comunidad de mejoradores.Sociedad Argentina de Informática e Investigación Operativ

Integración de herramientas informáticas para el diseño de marcadores moleculares ligados a un gen de interés a partir de un microarray de genotipado de trigo pan

El acceso a nuevas tecnologías moleculares para su aplicación en el mejoramiento de los cultivos demanda la utilización de herramientas informáticas de manera integrada para el tratamiento de los datos. Se presenta la confección de un mapa genético integrando 3232 SNP (en inglés, Single Nucleotide Polymorphism) obtenidos a partir de un microarray de SNP dise˜nado para trigo pan (Triticum aestivum) y 212 SSR (en inglés, Simple Sequence Repeat), utilizados previamente en el mapeo de una región cromosómica asociada a la resistencia de la Fusariosis de la Espiga de Trigo (FET), utilizando MapMerger y la librería RQTL. Se seleccionaron 15 SNP candidatos sobre los cuales se diseñaron cebadores in silico, para convertirlos en marcadores KASP (en ingles, Kompetitive allele-specific PCR), utilizando PolyMarker. Se espera contribuir con el desarrollo de un nuevo marcador asociado a un gen de resistencia a FET que pueda transferirse a la comunidad de mejoradores.Sociedad Argentina de Informática e Investigación Operativ