Transcriptional Regulation of Female and Male Flower Bud Initiation and Development in Pecan (Carya illinoensis)

Pecan (Carya illinoensis) nuts are delicious and rich in unsaturated fatty acids, which are beneficial for human health. Their yield is closely related to several factors, such as the ratio of female and male flowers. We sampled and paraffin-sectioned female and male flower buds for one year and determined the stages of initial flower bud differentiation, floral primordium formation, and pistil and stamen primordium formation. We then performed transcriptome sequencing on these stages. Our data analysis suggested that FLOWERING LOCUS T (FT) and SUPPRESSOR OF OVEREXPRESSION OF CONSTANS 1 play a role in flower bud differentiation. J3 was highly expressed in the early stage of female flower buds and may play a role in regulating flower bud differentiation and flowering time. Genes such as NF-YA1 and STM were expressed during male flower bud development. NF-YA1 belongs to the NF-Y transcription factor family and may initiate downstream events leading to floral transformation. STM promoted the transformation of leaf buds to flower buds. AP2 may have been involved in the establishment of floral meristem characteristics and the determination of floral organ characteristics. Our results lay a foundation for the control and subsequent regulation of female and male flower bud differentiation and yield improvement.

Automated summary

By sampling and paraffin-sectioning female and male flower buds of pecan (Carya illinoensis), we determined the different stages of flower bud differentiation and performed transcriptome sequencing. Data analysis revealed the involvement of FT and SOC1 in flower bud differentiation, with J3 playing a potential role in regulating flower bud differentiation and flowering time in female flower buds. Genes such as NF-YA1 and STM were found to be expressed during male flower bud development, where NF-YA1 may initiate downstream events leading to floral transformation and STM promoted the transformation from leaf buds to flower buds. AP2 possibly played a role in establishing floral meristem characteristics and determining floral organ characteristics. These findings provide a foundation for controlling and regulating female and male flower bud differentiation and improving yield.