Abstract:

YABBY genes family is a plant-specific transcription factor, which plays an important role in the development of plant leaves, floral organs and abiotic stress response, but it has not been reported in rubber tree so far. In this study, eleven HbYABBY genes were identified from the genome of Hevea brasiliensis, and the gene structure, promoter regulatory elements, chromosome location and collinearity, phylogeny and gene expression were analyzed. The results showed that the HbYABBY family genes were distributed on nine chromosomes. The length of the encoded protein was between 141 and 233 amino acids, and the molecular weight was ranged from 14.75 to 26.41kDa. The promoter regions contained response elements such as stress response, among which the number of light response elements was the largest. Gene transcriptional analysis showed that HbYABBY had significant tissue-specific expression profile, eight genes were only highly expressed in leaves and flowers but not in latex and roots. During the leaf development, except for HbCRC1, the expression of the other 9 HbYABBY were significantly down-regulated, which indicated that HbYABBY were deeply involved in the regulation of leaf development of rubber trees. Furthermore, both transcriptional and RT-qPCR experiments showed that HbYABBY genes were continuously down-regulated under high temperature treatment, indicating the regulatory roles in high temperature stress responses of rubber trees. In this paper, YABBY genes were firstly reported in H. brasiliensis, the physical and chemical characteristics, expressions and function of the genes were preliminarily studied, which would provide a solid foundation to investigate the functions and evolution of HbYABBY genes.

Key words: Hevea brasiliensis, YABBY genes family, transcription factor, gene expression analysis