Jointless gene of tomato

The present invention relates to the isolation and identification of a JOINTLESS gene from a tomato plant (genus Lycopersicon). More specifically, the invention relates to novel nucleic acid molecules isolated from a tomato plant, proteins encoded by such nucleic acid molecules, and antibodies raised against such proteins. The present invention is also directed to a nucleic acid homolog of a JOINTLESS gene and a method to identify a homolog in plants other than tomato

Construction, Characterization, and Preliminary BAC-End Sequence Analysis of a Bacterial Artificial Chromosome Library of the Tea Plant (Camellia sinensis)

We describe the construction and characterization of a publicly available BAC library for the tea plant, Camellia sinensis. Using modified methods, the library was constructed with the aim of developing public molecular resources to advance tea plant genomics research. The library consists of a total of 401,280 clones with an average insert size of 135 kb, providing an approximate coverage of 13.5 haploid genome equivalents. No empty vector clones were observed in a random sampling of 576 BAC clones. Further analysis of 182 BAC-end sequences from randomly selected clones revealed a GC content of 40.35% and low chloroplast and mitochondrial contamination. Repetitive sequence analyses indicated that LTR retrotransposons were the most predominant sequence class (86.93%–87.24%), followed by DNA retrotransposons (11.16%–11.69%). Additionally, we found 25 simple sequence repeats (SSRs) that could potentially be used as genetic markers

Ortholog Alleles at Xa3/Xa26 Locus Confer Conserved Race-Specific Resistance against Xanthomonas oryzae in Rice

The rice disease resistance (R) gene Xa3/Xa26 (having also been named Xa3 and Xa26) against Xanthomonas oryzae pv. oryzae (Xoo), which causes bacterial blight disease, belongs to a multiple gene family clustered in chromosome 11 and is from an AA genome rice cultivar (Oryza sativa L.). This family encodes leucine-rich repeat (LRR) receptor kinase-type proteins. Here, we show that the orthologs (alleles) of Xa3/Xa26, Xa3/Xa26-2, and Xa3/Xa26-3, from wild Oryza species O. officinalis (CC genome) and O. minuta (BBCC genome), respectively, were also R genes against Xoo. Xa3/Xa26-2 and Xa3/Xa26-3 conferred resistance to 16 of the 18 Xoo strains examined. Comparative sequence analysis of the Xa3/Xa26 families in the two wild Oryza species showed that Xa3/Xa26-3 appeared to have originated from the CC genome of O. minuta. The predicted proteins encoded by Xa3/Xa26, Xa3/Xa26-2, and Xa3/Xa26-3 share 91–99% sequence identity and 94–99% sequence similarity. Transgenic plants carrying a single copy of Xa3/Xa26, Xa3/Xa26-2, or Xa3/Xa26-3, in the same genetic background, showed a similar resistance spectrum to a set of Xoo strains, although plants carrying Xa3/Xa26-2 or Xa3/Xa26-3 showed lower resistance levels than the plants carrying Xa3/Xa26. These results suggest that the Xa3/Xa26 locus predates the speciation of A and C genome, which is approximately 7.5 million years ago. Thus, the resistance specificity of this locus has been conserved for a long time

Transposable element distribution, abundance and role in genome size variation in the genus Oryza

<p>Abstract</p> <p>Background</p> <p>The genus <it>Oryza </it>is composed of 10 distinct genome types, 6 diploid and 4 polyploid, and includes the world's most important food crop – rice (<it>Oryza sativa </it>[AA]). Genome size variation in the <it>Oryza </it>is more than 3-fold and ranges from 357 Mbp in <it>Oryza glaberrima </it>[AA] to 1283 Mbp in the polyploid <it>Oryza ridleyi </it>[HHJJ]. Because repetitive elements are known to play a significant role in genome size variation, we constructed random sheared small insert genomic libraries from 12 representative <it>Oryza </it>species and conducted a comprehensive study of the repetitive element composition, distribution and phylogeny in this genus. Particular attention was paid to the role played by the most important classes of transposable elements (Long Terminal Repeats Retrotransposons, Long interspersed Nuclear Elements, helitrons, DNA transposable elements) in shaping these genomes and in their contributing to genome size variation.</p> <p>Results</p> <p>We identified the elements primarily responsible for the most strikingly genome size variation in <it>Oryza</it>. We demonstrated how Long Terminal Repeat retrotransposons belonging to the same families have proliferated to very different extents in various species. We also showed that the pool of Long Terminal Repeat Retrotransposons is substantially conserved and ubiquitous throughout the <it>Oryza </it>and so its origin is ancient and its existence predates the speciation events that originated the genus. Finally we described the peculiar behavior of repeats in the species <it>Oryza coarctata </it>[HHKK] whose placement in the <it>Oryza </it>genus is controversial.</p> <p>Conclusion</p> <p>Long Terminal Repeat retrotransposons are the major component of the <it>Oryza </it>genomes analyzed and, along with polyploidization, are the most important contributors to the genome size variation across the <it>Oryza </it>genus. Two families of Ty3-<it>gypsy </it>elements (<it>RIRE2 </it>and <it>Atlantys</it>) account for a significant portion of the genome size variations present in the <it>Oryza </it>genus.</p

The Rice Paradox: Multiple Origins but Single Domestication in Asian Rice

The origin of domesticated Asian rice (Oryza sativa) has been a contentious topic, with conflicting evidence for either single or multiple domestication of this key crop species. We examined the evolutionary history of domesticated rice by analyzing de novo assembled genomes from domesticated rice and its wild progenitors. Our results indicate multiple origins, where each domesticated rice subpopulation (japonica, indica, and aus) arose separately from progenitor O. rufipogon and/or O. nivara. Coalescence-based modeling of demographic parameters estimate that the first domesticated rice population to split off from O. rufipogon was O. sativa ssp. japonica, occurring at ∼13.1–24.1 ka, which is an order of magnitude older then the earliest archeological date of domestication. This date is consistent, however, with the expansion of O. rufipogon populations after the Last Glacial Maximum ∼18 ka and archeological evidence for early wild rice management in China. We also show that there is significant gene flow from japonica to both indica (∼17%) and aus (∼15%), which led to the transfer of domestication alleles from early-domesticated japonica to proto-indica and proto-aus populations. Our results provide support for a model in which different rice subspecies had separate origins, but that de novo domestication occurred only once, in O. sativa ssp. japonica, and introgressive hybridization from early japonica to proto-indica and proto-aus led to domesticated indica and aus rice

DNA methylation changes facilitated evolution of genes derived from Mutator-like transposable elements

Supplementary file S2. Accession numbers and URLs for genome assembly, transcriptome and methylome data that used in this project. (DOCX 101 kb

Exceptional lability of a genomic complex in rice and its close relatives revealed by interspecific and intraspecific comparison and population analysis

<p>Abstract</p> <p>Background</p> <p>Extensive DNA rearrangement of genic colinearity, as revealed by comparison of orthologous genomic regions, has been shown to be a general concept describing evolutionary dynamics of plant genomes. However, the nature, timing, lineages and adaptation of local genomic rearrangement in closely related species (<it>e.g</it>., within a genus) and haplotype variation of genomic rearrangement within populations have not been well documented.</p> <p>Results</p> <p>We previously identified a hotspot for genic rearrangement and transposon accumulation in the <it>Orp </it>region of Asian rice (<it>Oryza sativa</it>, AA) by comparison with its orthologous region in sorghum. Here, we report the comparative analysis of this region with its orthologous regions in the wild progenitor species (<it>O. nivara</it>, AA) of Asian rice and African rice (<it>O. glaberrima</it>) using the BB genome <it>Oryza </it>species (<it>O. punctata</it>) as an outgroup, and investigation of transposon insertion sites and a segmental inversion event in the AA genomes at the population level. We found that <it>Orp </it>region was primarily and recently expanded in the Asian rice species <it>O. sativa </it>and <it>O. nivara</it>. LTR-retrotransposons shared by the three AA-genomic regions have been fixed in all the 94 varieties that represent different populations of the AA-genome species/subspecies, indicating their adaptive role in genome differentiation. However, LTR-retrotransposons unique to either <it>O. nivara </it>or <it>O. sativa </it>regions exhibited dramatic haplotype variation regarding their presence or absence between or within populations/subpopulations.</p> <p>Conclusions</p> <p>The LTR-retrotransposon insertion hotspot in the <it>Orp </it>region was formed recently, independently and concurrently in different AA-genome species, and that the genic rearrangements detected in different species appear to be differentially triggered by transposable elements. This region is located near the end of the short arm of chromosome 8 and contains a high proportion of LTR-retrotransposons similar to observed in the centromeric region of this same chromosome, and thus may represent a genomic region that has recently switched from euchromatic to heterochromatic states. The haplotype variation of LTR-retrotransposon insertions within this region reveals substantial admixture among various subpopulations as established by molecular markers at the whole genome level, and can be used to develop retrotransposon junction markers for simple and rapid classification of <it>O. sativa </it>germplasm.</p

The Amborella genome: an evolutionary reference for plant biology

The nuclear genome sequence of Amborella trichopoda, the sister species to all other extant angiosperms, will be an exceptional resource for plant genomics