Genome-Wide Identification and Expression Analysis of the RADIALIS-like Gene Family in Camellia sinensis

The RADIALIS-like (RL) proteins are v-myb avian myeloblastosis viral oncogene homolog (MYB)-related transcription factors (TFs), and are involved in many biological processes, including metabolism, development, and response to biotic and abiotic stresses. However, the studies on theRLgenes ofCamellia sinensisare not comprehensive enough. Therefore, we undertook this study and identified eightCsaRLsbased on the typical conserved domain SANT Associated domain (SANT) of RL. These genes have low molecular weights and theoretical pIvalues ranging from 5.67 to 9.76. Gene structure analysis revealed that sixCsaRLgenes comprise two exons and one intron, while the other two contain a single exon encompassing motifs 1 and 2, and part of motif 3. The phylogenetic analysis divided one hundred and fifty-eight RL proteins into five primary classes, in which CsaRLs clustered in Group V and were homologous with CssRLs of theShuchazaovariety. In addition, we selected different tissue parts to analyze the expression profile ofCsaRLs, and the results show that almost all genes displayed variable expression levels across tissues, withCsaRL1arelatively abundant in all tissues. qRT-PCR (real-time fluorescence quantitative PCR) was used to detect the relative expression levels of theCsaRLgenes under various abiotic stimuli, and it was found thatCsaRL1aexpression levels were substantially higher than other genes, with abscisic acid (ABA) causing the highest expression. The self-activation assay with yeast two-hybrid system showed that CsaRL1a has no transcriptional activity. According to protein functional interaction networks, CsaRL1a was well connected with WIN1-like, lysine histidine transporter-1-like, β-amylase 3 chloroplastic-like, carbonic anhydrase-2-like (CA2), and carbonic anhydrase dnaJC76 (DJC76). This study adds to our understanding of the RL family and lays the groundwork for further research into the function and regulatory mechanisms of theCsaRLsgene family inCamellia sinensis.Keywords:RADIALIS-like (RL);bioinformatics analysis;abiotic stress;self-activation;yeast two-hybrid system