Evolution of the apomixis transmitting chromosome in Pennisetum

BMC Evolutionary Biology

Research Article

Wayne W Hanna¹  Yukio Akiyama²  Joann A Conner²  Shailendra Goel²  Peggy Ozias-Akins²  Hitomi Yamada-Akiyama³ 

[1] Department of Crop and Soil Sciences, The University of Georgia, 2360 Rainwater Rd., 31793-5766, Tifton, GA, USA;Department of Horticulture, The University of Georgia, 2360 Rainwater Rd., 31793-5766, Tifton, GA, USA;Graduate School of Agriculture, Iwate University, 3-18-8 Ueda, 020-8550, Morioka, Iwate, Japan;

关键词: Bacterial Artificial Chromosome;    Bacterial Artificial Chromosome Clone;    rDNA Locus;    Chloroplast Gene;    Basic Chromosome Number;   

DOI  :  10.1186/1471-2148-11-289

 received in 2011-06-29, accepted in 2011-10-05,  发布年份 2011

来源: Springer

【 摘 要 】

BackgroundApomixis is an intriguing trait in plants that results in maternal clones through seed reproduction. Apomixis is an elusive, but potentially revolutionary, trait for plant breeding and hybrid seed production. Recent studies arguing that apomicts are not evolutionary dead ends have generated further interest in the evolution of asexual flowering plants.ResultsIn the present study, we investigate karyotypic variation in a single chromosome responsible for transmitting apomixis, the Apospory-Specific Genomic Region carrier chromosome, in relation to species phylogeny in the genera Pennisetum and Cenchrus. A 1 kb region from the 3' end of the ndhF gene and a 900 bp region from trnL-F were sequenced from 12 apomictic and eight sexual species in the genus Pennisetum and allied genus Cenchrus. An 800 bp region from the Apospory-Specific Genomic Region also was sequenced from the 12 apomicts. Molecular cytological analysis was conducted in sixteen Pennisetum and two Cenchrus species. Our results indicate that the Apospory-Specific Genomic Region is shared by all apomictic species while it is absent from all sexual species or cytotypes. Contrary to our previous observations in Pennisetum squamulatum and Cenchrus ciliaris, retrotransposon sequences of the Opie-2-like family were not closely associated with the Apospory-Specific Genomic Region in all apomictic species, suggesting that they may have been accumulated after the Apospory-Specific Genomic Region originated.ConclusionsGiven that phylogenetic analysis merged Cenchrus and newly investigated Pennisetum species into a single clade containing a terminal cluster of Cenchrus apomicts, the presumed monophyletic origin of Cenchrus is supported. The Apospory-Specific Genomic Region likely preceded speciation in Cenchrus and its lateral transfer through hybridization and subsequent chromosome repatterning may have contributed to further speciation in the two genera.

【 授权许可】

Unknown   
© Akiyama et al; licensee BioMed Central Ltd. 2011. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.