Hu Zhongli

Characterization and expression analysis of the expansin gene NnEXPA1 in lotus Nelumbo nucifera

Abstract Expansin proteins play a key role in inducing the extension and relaxation of plant cell walls. To understand the physiological role of expansins in lotus crop, Nelumbo nucifera Gaertn, during plant development, we cloned an expansin gene designated as NnEXPA1 using the rapid amplification of cDNA ends technique. The full-length cDNA of NnEXPA1 was 1,456 bp encoding a protein of 250 amino acids. Gene structure of NnEXPA1 showed that it cosists of three exons and two introns. Phylogenetic tree and sequence analysis indicated that NnEXPA1 belongs to theα -expansin subfamily. Results of the real-time semi-quantitative PCR demonstrated that NnEXPA1 were difierentially expressed within all tissues except root during the plant development. Expression of NnEXPA1 in leaf and rhizome were dramatically decreased during the initial to later stages of rhizome-development. In lotus root, however, NnEXPA1 seemed to exhibit a stable expression pattern. Our results indicated that the transcript accumulation of NnEXPA1 between the initial and early stages of rhizome development may be an important factor during rhizome size determination.