@article {398, title = {Genomics of the origin and evolution of Citrus.}, journal = {Nature}, volume = {554}, year = {2018}, month = {2018 02 15}, pages = {311-316}, abstract = {

The genus Citrus, comprising some of the most widely cultivated fruit crops worldwide, includes an uncertain number of species. Here we describe ten natural citrus species, using genomic, phylogenetic and biogeographic analyses of 60 accessions representing diverse citrus germ plasms, and propose that citrus diversified during the late Miocene epoch through a rapid southeast Asian radiation that correlates with a marked weakening of the monsoons. A second radiation enabled by migration across the Wallace line gave rise to the Australian limes in the early Pliocene epoch. Further identification and analyses of hybrids and admixed genomes provides insights into the genealogy of major commercial cultivars of citrus. Among mandarins and sweet orange, we find an extensive network of relatedness that illuminates the domestication of these groups. Widespread pummelo admixture among these mandarins and its correlation with fruit size and acidity suggests a plausible role of pummelo introgression in the selection of palatable mandarins. This work provides a new evolutionary framework for the genus Citrus.

}, keywords = {Asia, Southeastern, Biodiversity, citrus, Crop Production, Evolution, Molecular, Genetic Speciation, Genome, Plant, Genomics, Haplotypes, Heterozygote, History, Ancient, Human Migration, Hybridization, Genetic, Phylogeny}, issn = {1476-4687}, doi = {10.1038/nature25447}, author = {Wu, Guohong Albert and Terol, Javier and Iba{\~n}ez, Victoria and L{\'o}pez-Garc{\'\i}a, Antonio and P{\'e}rez-Rom{\'a}n, Estela and Borred{\'a}, Carles and Domingo, Concha and Tadeo, Francisco R and Carbonell-Caballero, Jos{\'e} and Alonso, Roberto and Curk, Franck and Du, Dongliang and Ollitrault, Patrick and Roose, Mikeal L and Dopazo, Joaquin and Gmitter, Frederick G and Rokhsar, Daniel S and Talon, Manuel} } @article {563, title = {Involvement of a citrus meiotic recombination TTC-repeat motif in the formation of gross deletions generated by ionizing radiation and MULE activation}, journal = {BMC Genomics}, volume = {16}, year = {2015}, month = {Feb}, pages = {69}, abstract = {Transposable-element mediated chromosomal rearrangements require the involvement of two transposons and two double-strand breaks (DSB) located in close proximity. In radiobiology, DSB proximity is also a major factor contributing to rearrangements. However, the whole issue of DSB proximity remains virtually unexplored.}, issn = {1471-2164}, doi = {10.1186/s12864-015-1280-3}, url = {https://doi.org/10.1186/s12864-015-1280-3}, author = {Terol, Javier and Iba{\~n}ez, Victoria and Carbonell, Jos{\'e} and Alonso, Roberto and Estornell, Leandro H. and Licciardello, Concetta and Gut, Ivo G. and Dopazo, Joaquin and Talon, Manuel} } @article {1115, title = {Involvement of a citrus meiotic recombination TTC-repeat motif in the formation of gross deletions generated by ionizing radiation and MULE activation.}, journal = {BMC genomics}, volume = {16}, year = {2015}, month = {2015 Feb 13}, pages = {69}, abstract = {BACKGROUND: Transposable-element mediated chromosomal rearrangements require the involvement of two transposons and two double-strand breaks (DSB) located in close proximity. In radiobiology, DSB proximity is also a major factor contributing to rearrangements. However, the whole issue of DSB proximity remains virtually unexplored. RESULTS: Based on DNA sequencing analysis we show that the genomes of 2 derived mutations, Arrufatina (sport) and Nero (irradiation), share a similar 2 Mb deletion of chromosome 3. A 7 kb Mutator-like element found in Clemenules was present in Arrufatina in inverted orientation flanking the 5{\textquoteright} end of the deletion. The Arrufatina Mule displayed "dissimilar" 9-bp target site duplications separated by 2 Mb. Fine-scale single nucleotide variant analyses of the deleted fragments identified a TTC-repeat sequence motif located in the center of the deletion responsible of a meiotic crossover detected in the citrus reference genome. CONCLUSIONS: Taken together, this information is compatible with the proposal that in both mutants, the TTC-repeat motif formed a triplex DNA structure generating a loop that brought in close proximity the originally distinct reactive ends. In Arrufatina, the loop brought the Mule ends nearby the 2 distinct insertion target sites and the inverted insertion of the transposable element between these target sites provoked the release of the in-between fragment. This proposal requires the involvement of a unique transposon and sheds light on the unresolved question of how two distinct sites become located in close proximity. These observations confer a crucial role to the TTC-repeats in fundamental plant processes as meiotic recombination and chromosomal rearrangements.}, issn = {1471-2164}, doi = {10.1186/s12864-015-1280-3}, url = {http://www.biomedcentral.com/1471-2164/16/69}, author = {Terol, Javier and Iba{\~n}ez, Victoria and Carbonell, Jos{\'e} and Alonso, Roberto and Estornell, Leandro H and Licciardello, Concetta and Gut, Ivo G and Joaqu{\'\i}n Dopazo and Talon, Manuel} } @article {1121, title = {A phylogenetic analysis of 34 chloroplast genomes elucidates the relationships between wild and domestic species within the genus Citrus.}, journal = {Molecular biology and evolution}, volume = {32}, number = {8}, year = {2015}, month = {2015 Apr 14}, pages = {2015-2035}, abstract = {Citrus genus includes some of the most important cultivated fruit trees worldwide. Despite being extensively studied because of its commercial relevance, the origin of cultivated citrus species and the history of its domestication still remain an open question. Here we present a phylogenetic analysis of the chloroplast genomes of 34 citrus genotypes which constitutes the most comprehensive and detailed study to date on the evolution and variability of the genus Citrus. A statistical model was used to estimate divergence times between the major citrus groups. Additionally, a complete map of the variability across the genome of different citrus species was produced, including single nucleotide variants, heteroplasmic positions, indels and large structural variants. The distribution of all these variants provided further independent support to the phylogeny obtained. An unexpected finding was the high level of heteroplasmy found in several of the analysed genomes. The use of the complete chloroplast DNA not only paves the way for a better understanding of the phylogenetic relationships within the Citrus genus, but also provides original insights into other elusive evolutionary processes such as chloroplast inheritance, heteroplasmy and gene selection.}, keywords = {chloroplast, citrus, Phylogeny, WGS}, issn = {1537-1719}, doi = {10.1093/molbev/msv082}, url = {http://mbe.oxfordjournals.org/content/early/2015/04/27/molbev.msv082.full}, author = {Carbonell-Caballero, Jos{\'e} and Alonso, Roberto and Iba{\~n}ez, Victoria and Terol, Javier and Talon, Manuel and Dopazo, Joaquin} }