The Yabby Gene Network in Sunflower:Evolutionary Dynamics and Drought-Responsive Expression Profiling

OpenAlex İngilizce

The YABBY gene family, known for its plant-specific transcription factors, plays pivotal roles in regulating leaf polarity, floral organ development, and responses to environmental stimuli. Despite its functional importance in various plant species, a comprehensive understanding of this gene family in sunflower (Helianthus annuus L.) has remained elusive. In this study, we conducted a genome-wide in silico identification and characterization of YABBY genes in H. annuus, revealing 14 HaYABBY members distributed across 10 chromosomes. Phylogenetic analysis clustered these genes into five conserved subfamilies (FIL/YAB3, YAB2, YAB5, INO, and CRC), while gene structure and motif analyses highlighted both conserved domain architecture and subfamily-specific divergence. Promoter analysis revealed the presence of multiple stress- and hormone-responsive cis-elements, and miRNA target prediction identified HaYABBY05 and HaYABBY09 as potential post-transcriptional targets of four distinct miRNAs. Synteny and duplication analyses suggested that segmental duplication events under purifying selection contributed to the expansion and conservation of HaYABBY genes. Tissue-specific expression profiling via RNA-seq demonstrated diverse expression patterns, with HaYABBY05 exhibiting broad expression and HaYABBY12 showing strong floral organ specificity. Under drought stress, RNA-seq and RT-qPCR analyses revealed significant cultivar- and tissue-specific expression differences between the drought-tolerant (SUN 2235) and drought-sensitive (Turay) sunflower cultivars. Notably, HaYABBY genes showed strong induction in the roots of SUN 2235 but were suppressed in Turay, implicating a potential role in drought adaptation. Together, these findings provide the first comprehensive insight into the structure, evolution, and stress-responsive expression of YABBY genes in sunflower. This study offers valuable candidate genes and regulatory clues for improving drought resilience in sunflower breeding and sets a foundation for further functional exploration of YABBY transcription factors in crops.