HaYABBY Gene Is Associated with the Floral Development of Ligulate-Like Tubular Petal Mutant Plants of Sunflower

Abstract

As an ornamental organ, petal plays an important role in attracting insect pollination, it’s development attracts the attention of many researchers. In this study, a sunflower mutant line with ligulate-like tubular petal (lpm) was screened out, and its disc tubular florets were characterized with elongated ligulate-like petals, longer filaments size, fewer anthers and lower seed setting rate, compared with wide type (WT) plants. From the suppression subtractive hybridization library constructed using inflorescence of lpm and WT plants, the HaYABBY was identified with expressing differentially. The cDNA and structural sequences of HaYABBY gene were 997 and 4339 bp, respectively, encoding a peptide with 219 amino acids. The analysis of HaYABBY expression showed that it presented higher transcription level in flower than root, stem and leaf of sunflower. The expression level of YABBY in disc florets of lpm was significantly higher than those of WT, especially at early floral developmental stage. The results suggested that HaYABBY could impact the floral development at early stage, particularly on petal elongation and floral symmetry morphogenesis in sunflower. Furthermore, the results implied that HaYABBY would be involved in the regulation of reproductive system development and affect their fertility. Our findings will provide some insight to understand the regulating network of floral development in sunflower, and help to cultivate new sunflower varieties with high ornamental value.