The Role of Small RNAs in the Formation of Polyploid Brassica

Hybridization in plants combines different genomes in the same cell, and genome "shock" and instability occur during this process. Chromosome doubling then reconstructs the genome dosage. Recent studies have shown that small RNAs play an important role in maintaining genome stability. However, little is known of small RNA's role during wide hybridization and chromosome doubling. Therefore, Liping Chen of Zhejiang University in China studied the genetic and DNA methylation alterations and changes in the siRNA and miRNA during the formation of the allodiploid and allotetraploid between Brassica rapa and Brassica nigra.

The expression of miRNAs increased in the allodiploid and allotetraploid compared with the parents, while the levels of siRNAs was found higher compared to B. rapa but lower compared with B. nigra. As the polyploidy increases, the levels of miRNAs increased, suggesting its role in regulating gene expression. On the other hand, levels of siRNAs and DNA methylation alterations decreased as the ploidy increased and become more stable. These results may provide new information for understanding that the allotetraploids have a growth advantage over the parents and the allodiploids.

To learn more about this study, read the full article here: http://www.biomedcentral.com/content/pdf/s12870-014-0272-9.pdf.