Genome-wide analysis of the NYN domain gene family in Brassica napus and its function role in plant growth and development

The NYN domain gene family consists of genes that encode ribonucleases that are characterized by a newly identified NYN domain. Members of the family were widely distributed in all life kingdoms and play a crucial role in various RNA regulation processes, although the wide genome overview of the NYN domain gene family is not yet available in any species. Rapeseed (Brassica napus L.), a polyploid model species, is an important oilseed crop. Here, the phylogenetic analysis of these BnaNYNs revealed five distinct groups strongly supported by gene structure, conserved domains, and conserved motifs. The survey of the expansion of the gene family showed that the birth of BnaNYNs is explained by various duplication events. Furthermore, tissue-specific expression analysis, protein-protein interaction prediction, and cis-element prediction suggested a role for BnaNYNs in plant growth and development. Interestingly, the data showed that three tandem duplicated BnaNYNs (TDBs) exhibited distinct expression patterns from those other BnaNYNs and had a high similarity in protein sequence level. Furthermore, the analysis of one of these TDBs, BnaNYN57, showed that overexpression of BnaNYN57 in Arabidopsis thaliana and B. napus accelerated plant growth and significantly increased silique length, while RNA interference resulted in the opposite growth pattern. It suggesting a key role for the TDBs in processes related to plant growth and development.