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Cloning and Characterization of Importin α in Brassica napus L.
Author(s) -
Wang Daojie,
Yang Cuiling,
Lu Ming,
Huang Fei,
Guo Aiguang,
Song Chunpeng
Publication year - 2013
Publication title -
crop science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.76
H-Index - 147
eISSN - 1435-0653
pISSN - 0011-183X
DOI - 10.2135/cropsci2013.03.0174
Subject(s) - biology , genetics , intron , arabidopsis , gene , microbiology and biotechnology , mutant
A previously identified genic male sterile (GMS) line in Brassica napus L. (rapeseed), in which the male sterile trait is controlled by a monogenic dominant locus, has been designated as MDGMS. In this study, we cloned importin‐α‐like sequences in MDGMS and its allelic fertile line. When we compared complementary DNA (cDNA) and deduced amino acid sequences of both cloned regions, several mutations were detected between the two lines. Sequence analysis revealed that the cloned gene contains 10 exons and 9 introns, consistent with IMPa‐4 in Arabidopsis spp., and it was accordingly designated as BnIMPα ( Brassica napus importin α ). Splice junctions of all introns in BnIMP α follow the GT–AG rule, and the amino acid sequence of BnIMPα contains the nuclear localization signal (NLS) sequence RKKIYKTGVDADEARRRR. The BnIMPα protein possesses characteristic features of importin α, such as an importin β binding (IBB) domain, eight tandem armadillo (ARM) repeats, and two helix–turn–helix motifs (HEAT) repeats. BnIMP α ribonucleic acid interference (RNAi) resulted in sterility or reduced fertility of male and female gametes, indicating that BnIMP α is necessary for gametogenesis in B. napus . Compared with the wild‐type, RNAi plants were highly susceptible to downy mildew and viral diseases. Tissue and subcellular localization analysis indicated that BnIMP α is expressed in all plant tissues other than seeds, especially conducting tissue and stamens, and that BnIMPα is localized in the nucleus.