Abstract

Mongol mulberry is one of the wild species of genus Morus, and mainly grows in cold regions. In this study, stem cuttings of Mongol mulberry were acclimated at 0°C for 48 h after germination. RNA was extracted form the stem and was reverse-transcribed into cDNA. Mulberry low-temperature induced gene WAP25 was then cloned by means of RT-PCR technique. The cloned gene has been submitted to GenBank (Accession N0. DQ104333). Analysis indicated that the WAP25 is 681 bp in length, encoding 226 amino acids. It is also confirmed that the product encoded by WAP25 is a member of late embryogenesis abundant protein (LEA) family. DNA fragment of WAP25 was cloned into plasmid pIG121-Hm to generate plant expression vector pIG121/Wap25. pIG121/Wap25 was then transformed into leaf discs of Petunia hybrida Vilm mediated by Agrobacterium to obtain 34 transformants, 11.48% of which are positive by the detection of PCR-Southern assay. The results provide theoretical basis for research of genetic improvement in cold resistance of mulberry and low temperature response mechanism of woody plants.

Key words: Mulberry, low-temperature-inducible gene, Petunia hybrida Vilm, transformation.