Transcriptome-wide identification and characterization of WD40 genes, as well as their tissue-specific expression profiles and responses to heat stress in Dimocarpus longan Lour.

The WD40 transcription factor (TF) family is widespread in plants and plays important roles in plant growth and development, transcriptional regulation, and tolerance to abiotic stresses. WD40 TFs have been identified and characterized in a diverse series of plant species. However, little information is available on WD40genes from D. longan. In this study, a total of 45 DlWD40genes were identified from D. longan RNASeq data, and further analysed by bioinformatics tools. Also, the expression patterns of DlWD40genes in roots and leaves, as well as responses to heat stress, were evaluated using quantitative real-time PCR (qRT-PCR). We found that the 45 DlWD40 proteins, together with 80 WD40 proteins from Arabidopsis and Zea mays, could be categorized into six groups. Of these, the DlWD40-4 protein was highly homologous to Arabidopsis WDR5a, a protein participating in tolerance to abiotic stresses. Moreover, a total of 25 cis-acting elements, such as abiotic stress and flavonoid biosynthesis elements, were found in the promoters of DlWD40genes. The DlWD40-33 gene is targeted by miR3627, which has been proposed to be involved in flavonoid biosynthesis. Using qRT-PCR, ten of the 45 DlWD40genes were demonstrated to have diverse expression patterns between roots and leaves, and these ten DlWD40genes could also respond to varying durations of a 38 ?C heat stress in roots and leaves. The results reported here will provide a basis for the further functional verification of DlWD40 genes in D. longan.