Identification and analysis of the MYB transcription factors against seawater tolerance in daylily (Hemerocallis fulva L.).

The MYB transcription factor family, one of the largest in plants, plays a crucial role in responding to abiotic stress responses. Daylily (Hemerocallis fulva L.) is a salt-tolerant plant ideal for coastal landscaping. In this study, we identified 33 MYB transcription factors from the 'Autumn Red' daylily roots under seawater stress, a discovery reported here for the first time. Chromosome mapping revealed an uneven distribution of these genes, with numerous segmental and tandem repeats. Phylogenetic analysis with Arabidopsis and rice MYBs classified the daylily MYBs into six subfamilies, which were further divided into five subclasses based on conserved domains. Expression profiling across different seawater treatment periods revealed distinct H, L, and M expression patterns. Through an integrated analysis of phylogeny, motif structure, and expression profiles, we identified HfMYB10 as a key candidate. Heterologous expression of HfMYB10 in Arabidopsis yielded homozygous transgenic linesexhibiting significantly enhanced seawater tolerance. Our findings clarify the role of daylily MYB transcription factors in seawater tolerance and offer valuable insights for breeding salt-resistant varieties.