A Genetic Linkage Map of Diploid <i>Paspalum notatum</i>

Ortiz, Juan Pablo Amelio; Pessino, Silvina Claudia; Bhat, Vishnu; Hayward, M. D.; Quarín, Camilo Luis

doi:10.2135/cropsci2001.413823x

Cited by 22 publications

(19 citation statements)

References 36 publications

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“…Gels were stained by using the DNA Silver Staining System (Promega). RFLP markers were assayed on a sample of 30 individuals from the F1 progeny (15 aposporous and 15 randomly chosen sexual plants), as described by Ortiz et al (2001).…”

Section: Molecular Marker Generationmentioning

confidence: 99%

Gene expression analysis at the onset of aposporous apomixis in Paspalum notatum

et al. 2008

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Apomixis is a route of asexual reproduction through seeds, that progresses in the absence of meiosis and fertilization to generate maternal clonal progenies. Gametophytic apomicts are usually polyploid and probably arose from sexual ancestors through a limited number of mutations in the female reproductive pathway. A differential display analysis was carried out on immature inflorescences of sexual and apomictic tetraploid genotypes of Paspalum notatum, in order to identify genes associated with the emergence of apospory. Analysis of approximately 10,000 transcripts led to the identification of 94 high-quality differentially expressed sequences. Assembling analysis, plus validation, rendered 65 candidate unigenes, organized as 14 contigs and 51 singletons. Thirty-four unigenes were isolated from apomictic plants and 31 from sexual ones. A total of 45 (69.2%) unigenes were functionally categorized. While several of the differentially expressed sequences appeared to be components of an extracellular receptor kinase (ERK) signal transduction cascade, others seemed to participate in a variety of central cellular processes like cell-cycle control, protein turnover, intercellular signalling, transposon activity, transcriptional regulation and endoplasmic reticulum-mediated biosynthesis. In silico mapping revealed that a particular group of five genes silenced in apomictic plants clustered in a rice genomic area syntenic with the region governing apospory in Paspalum notatum and Brachiaria brizantha. Two of these genes mapped within the set of apo-homologues in P. notatum. Four genes previously reported to be controlled by ploidy were identified among those expressed differentially between apomictic and sexual plants. In situ hybridization experiments were performed for selected clones.

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Section: Molecular Marker Generationmentioning

confidence: 99%

Gene expression analysis at the onset of aposporous apomixis in Paspalum notatum

et al. 2008

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“…Moreover, for avoiding the inclusion in the study of markers clustered in specific genomic regions, a linkage analysis was carried out by using Joinmap 1.4 (Stam 1993). Segregation data were tested as dominant loci derived from a pseudo-test cross or an F 2 for families H 1 and S 1 , respectively, at a minimum LOD score of 3.0 according to Ortiz et al (2001).…”

Section: Dna Extraction and Molecular Markers Assaysmentioning

confidence: 99%

Genetic and embryological evidences of apomixis at the diploid level in Paspalum rufum support recurrent auto-polyploidization in the species

et al. 2008

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Gametophytic apomixis is an asexual mode of reproduction by seeds. This trait is present in several plant families and is strongly associated with polyploidy. Paspalum rufum is a forage grass with sexual self-incompatible diploids (2n = 2x = 20) and aposporous-apomictic pseudogamous tetraploids (2n = 4x = 40). In previous work embryological observations of the diploid genotype Q3754 showed 8.8-26.8% of the ovaries having one meiotic plus an aposporous-like embryo sac, suggesting some capability for apomictic reproduction. The objective of this work was to characterize progenies derived from Q3754 to determine if aposporous sacs were functional and generated progenies via apomixis at the diploid level. Re-examination of Q3754 ovaries showed that 12.5% of them contained one sexual plus an aposporous sac confirming previous results. Progeny tests were carried out on two experimental families (H 1 and S 1 ) employing heterozygous RAPD marker loci. Family H 1 was obtained crossing Q3754 with a natural diploid genotype (Q3861) and S 1 derived from the induced self-pollination of Q3754. Genetic analysis of H 1 showed that all individuals derived from sexual reproduction. However, 5 out of 95 plants from S 1 showed the same heterozygous state as the mother plant for 14 RAPD loci suggesting a clonal origin. Further experiments, designed to test the functionality of aposporous sacs by flow cytometric analyses, were carried out on a third family (M 1 ) obtained by crossing Q3754 with the tetraploid plant Q3785. Histograms of 20 M 1 plants showed 15 diploids (75%), 4 triploids (20%) and 1 tetraploid (5%). Triploids and the tetraploid may have originated from functional aposporous embryo sacs. Likewise, the reconstruction of the developmental route of 40 individual seeds demonstrated that 11 of them (27.5%) derived from fertilized aposporic sacs. The results presented in this work indicate that gametophytic apomixis is effectively expressed at the diploid level in Paspalum rufum and could be the foundation of a recurrent auto-polyploidization process in the species.

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“…A genetic linkage map was constructed from Paspalum notatum (Ortiz et al 2001) and currently, no genetic linkage map is available for Paspalum vaginatum. Therefore, a segregating population will be generated for the construction of a genetic linkage map for Paspalum vaginatum.…”

Section: Adequate Number Of Dna Markers For Germplasm Characterizatiomentioning

confidence: 99%

Characterization of Seashore Paspalum (Paspalum vaginatum Swartz) Germplasm by Transferred SSRs from Wheat, Maize and Sorghum

Wang¹,

Chen

Barkley³

et al. 2006

Genet Resour Crop Evol

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One hundred and thirty SSR markers from wheat, maize and sorghum were screened for the transferability to Paspalum. The transfer rate was 67.5, 49.0 and 66.8% respectively. This would be a very efficient approach for DNA marker development for species which are not well studied molecularly. The polymorphism level for transferred SSR markers was 51.5% within species (Paspalum vaginatum) and 87.1% among Paspalum species. The high level of polymorphism is directly related to the high degree of heterozygosity maintained by its way of reproduction, i.e. self-incompatibility. Forty transferred polymorphic SSR markers were selected and used for characterization and evaluation of seventy-three Paspalum accessions. In total, 209 polymorphic bands were detected from these 40 SSR markers, with an average of five polymorphic bands per marker. The Paspalum accessions clustered into three major groups. Two very similar dendrograms can be generated from either 109 or 209 polymorphic bands. This led us to determine that 18 of the transferred SSR markers were sufficient for genetically differentiating the investigated germplasm accessions. The number of SSR markers required for germplasm characterization and evaluation is discussed. This is the first report of the transfer of SSR markers from major field crops to newly emerged environmental turfgrasses.

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A Genetic Linkage Map of Diploid Paspalum notatum

Cited by 22 publications

References 36 publications

Gene expression analysis at the onset of aposporous apomixis in Paspalum notatum

Gene expression analysis at the onset of aposporous apomixis in Paspalum notatum

Genetic and embryological evidences of apomixis at the diploid level in Paspalum rufum support recurrent auto-polyploidization in the species

Characterization of Seashore Paspalum (Paspalum vaginatum Swartz) Germplasm by Transferred SSRs from Wheat, Maize and Sorghum

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