Tiger nut is the tuber of the perennial herbaceous plant Cyperus esculentus L., whose unique underground tubers are not only the main reproductive organ but also an important oil storage site. Oleosin is the most abundant structural protein in the oil body, which is an important membrane structural protein, playing a role in the formation and stability of lipid droplets in oilseed crops. Most studies have focused on the oleosin in oilseeds, but rarely on the oil containing tuber. In this study, nine oleosin genes from the Cyperus esculentus transcriptome were identified and divided into two groups via phylogenetic analysis. The expression patterns of the nine oleosins were examined through quantitative real-time PCR (qRT-PCR) in various development stages of stem tissue (35 d, 50 d, 75 d, 90 d, and 120 d after sowing). The subcellular localization of CeOle4 indicated that this protein was localized exclusively to membrane, indicating that it functioned in the plasma membrane. The highly expressed gene CeOle4 within the CeOleosin gene family was further transformed into yeast cells and plant materials. The results demonstrate that CeOle4 can promote lipid synthesis, enhancing the stability of oil lipids at low temperature and changing seed phenotypic traits. This discovery addresses and enriches the research on the function of CeOleosin genes and lays the groundwork for future studies on novel and superior transgenic crops related to tiger nut.

Safflower (Carthamus tinctorius L.) is a traditional economic crop in China valued for its medicinal petals and high-quality seed oil. Despite the importance of floret number and capitulum architecture for petal yield in safflower, the molecular regulators linking auxin signaling to inflorescence development in this species remain poorly understood. Auxin response factors (ARFs) are key transcriptional regulators mediating auxin-responsive gene expression and developmental processes, yet their functions in safflower inflorescence development have not been systematically investigated. In this study, we identified 25 CtARF genes from the safflower genome and classified them into five phylogenetic subfamilies. Cis-regulatory analysis predicted the presence of hormone- and development-related elements in CtARF-associated promoter regions. Expression profiling revealed that CtARF4, a member of the CtARF III subfamily, exhibits preferential expression during flower development. CtARF4 was localized to the nucleus and shown to interact with the CtMADS24 promoter and the Aux/IAA protein CtIAA9 in heterologous systems. Transient overexpression of CtARF4 increased floret number and length and promoted flowering, whereas virus-induced gene silencing resulted in opposite phenotypes. In addition, CtARF4 perturbation was associated with a reduction in IAA content as measured by a kit-based assay. Collectively, these findings suggest that CtARF4 functions as an auxin-responsive transcriptional regulator contributing to inflorescence development in safflower.