Identification of AUXIN RESPONSE FACTOR gene family from Prunus sibirica and its expression analysis during mesocarp and kernel development.

BACKGROUND: Auxin response factors (ARFs) in auxin signaling pathway are an important component that can regulate the transcription of auxin-responsive genes involved in almost all aspects of plant growth and development. To our knowledge, the comprehensive and systematic characterization of ARF genes has never been reported in Prunus sibirica, a novel woody biodiesel feedstock in China.

RESULTS: In this study, we identified 14 PsARF genes with a perfect open reading frame (ORF) in P. sibirica by using its previous transcriptomic data. Conserved motif analysis showed that all identified PsARF proteins had typical DNA-binding and ARF domain, but 5 members (PsARF3, 8 10, 16 and 17) lacked the dimerization domain. Phylogenetic analysis of the ARF proteins generated from various plant species indicated that ARFs could be categorized into 4 major groups (Class I, II, III and IV), in which all identified ARFs from P. sibirica showed a closest relationship with those from P. mume. Comparison of the expression profiles of 14 PsARF genes in different developmental stages of Siberian apricot mesocarp (SAM) and kernel (SAK) reflected distinct temporal or spatial expression patterns for PsARF genes. Additionally, based on the expressed data from fruit and seed development of multiple plant species, we identified 1514 ARF-correlated genes using weighted gene co-expression network analysis (WGCNA). And the major portion of ARF-correlated gene was characterized to be involved in protein, nucleic acid and carbohydrate metabolic, transport and regulatory processes.

CONCLUSIONS: In summary, we systematically and comprehensively analyzed the structure, expression pattern and co-expression network of ARF gene family in P. sibirica. All our findings provide theoretical foundation for the PsARF gene family and will pave the way for elucidating the precise role of PsARF genes in SAM and SAK development.