Isolation of Tripsacum dactyloides genes using putative apomixis genes from Pennisetum ciliare
In the present study, DNA sequences associated with an apomixis gene inPennisetum ciliare were isolated from a distantly related grass species, Tripsacum dactyloides. Primers were developed for two bioinformatics-identified candidate genes (Pca2l and Pca24) for apomixis in Pennisetum ciliare. Homologous gene sequences were successfully isolated from both diploid (2n=36) and tetraploid (4n=72) Tripsacum using the primers and polymerase chain reaction (PCR) amplification. Bioinformatics analysis of the purified, cloned and sequenced PCR products revealed that the isolated homolog of the Pca2l gene varies significantly between the diploid and the tetraploid Tripsacum. Comparative genome analyses against Oryza, Zea, Arabidopsis, Pennisetum, Tripsacum and the National Center for Biotechnology Information (NCBI) nucleotide collection (nr) have shown that the PCR-generated sequences are reproductive specific. Analysis of the Trip2lT3c sequence was shown to be a Rab2 homolog with an e-value of 9e-23. Further proteomics analyses of the putative gene products have revealed that the Pca2l and the Tripsacum sequences may be partially conserved, with the Trip2lT3c sequence more highly conserved than the Trip21D3a.