Xinglong Wang

A novel ABA-dependent dehydrin ERD10 gene from Brassica napus.

A new dehydrin ERD10 gene was cloned and characterized from Brassica napus (designated as Bndhn ERD10). The full-length cDNA of Bndhn ERD10 was 1114 bp and contained an open reading frame of 816 bp encoding a protein of 271 amino acid residues. The deduced Bndhn ERD10 protein contained an 8-serine residue domain and two conserved repeats of the characterized lysine-rich-K-segment (KIKEKLPG). Analysis of full-length cDNA and genomic DNA indicated that there were no introns in Bndhn ERD10 gene. The promoter of Bndhn ERD10 was further obtained by genomic walking technology, and analysis of the promoter indicated that the regulation of Bndhn ERD10 was ABA-dependent. Semi-quantitative RT-PCR of different tissues in unstressed B. napus plants indicated that the transcript of Bndhn ERD10 was more abundant in leaf than in stem and root. The expression profiles of Bndhn ERD10 in B. napus seedlings under various stress conditions including cold, salt and ABA were also investigated. Upon cold, salt and ABA stresses, increased transcript accumulations of the Bndhn ERD10 mRNAs were detected in young leaves 8 h after treatment.

Molecular cloning and characterization of a novel ice gene from Capsella bursa-pastoris

A new ice gene (designated as Cbice53, an inducer of CBF expression) was cloned from Capsella bursa-pastoris by rapid amplification of cDNA ends (RACE). The full-length cDNA of Cbice53 was 1811 bp long, with a 1476-bp open reading frame (ORF) encoding a Myc-like protein of 492 amino acids. The predicted CbICE53 protein contained a potential basic helix-loop-helix domain, a nuclear localization signal (NLS), an RNA-binding region (RGG box), and N-glycosylation and kinase phosphorylation sites. Bioinformatic analysis showed that CbICE53 was highly homologous to ICE1 from Arabidopsis thaliana. Transcription of Cbice53 gene was induced transiently during salt and cold treatments, suggesting that it was somehow involved in cold acclimation. The results of our study indicate that the Cbice53 gene is a new member of the ice gene family and may have a role in cold and salt responsiveness in C. bursa-pastoris.

Molecular cloning and characterization of cold-responsive gene Cbrci35 from Capsella bursa-pastoris

A new rare cold-inducible (RCI) gene designated Cbrci35 was cloned from Capsella bursa-pastoris, an edible wild herb, using the rapid amplification of cDNA ends (RACE) method. The full-length cDNA of Cbrci35 (Database Accession No.: AY566573) was 1300 bp and contained a 978 bp ORF encoding a precursor of 326 amino acid residues with a 23 amino acids signal peptide. The predicted Cbrci35 protein contained a peroxidase active site and proximal heme-ligand signatures, an RGD cell attachment sequence motif and two leucine zipper pattern motifs. Bioinformatics analysis revealed that Cbrci35 has a high level of similarity with RCI genes from Arabidopsis thaliana and peroxidases genes from other plants. RT-PCR analysis revealed that Cbrci35 expressed only in root. A cold acclimation assay showed that Cbrci35 was expressed immediately after cold triggering, but this expression was transient, suggesting that it concerns cold acclimation. But expression was not induced exposed to dehydration, salt stress or abscisic acid, indicating that it might be subjected specifically to cold regulation. These results indicate that Cbrci35 is an analogue of RCI genes and may participate in cold-response or increasing the freezing tolerance of plants.

[Isolation and expression profiling of the Pto-like gene SsPto from Solanum surattense].

A novel Pto-like gene (designated as SsPto) is cloned from yellow-fruit nightshade (Solanum surattense). The full-length cDNA of SsPto is 1331 bp long with an open reading frame of 960 bp encoding a polypeptide of 320 amino acid residues. The deduced SsPto protein has a calculated molecular weight of 36.21 kDa with an isoelectric point of 6.18. Multiple sequence alignment shows that the SsPto protein shares 71.4% and 71.6% identities with Pto proteins from Lycopersicon pimpinellifolium and L. hirsutum, respectively. Genomic Southern blot analysis indicates the presence of a small family of SsPto in the S. surattense genome. SsPto is found to be constitutively expressed in the S. surattense plant with the highest expression in stems. However, under induction by TMV for 6 days, SsPto is expressed the highest in roots. Further expression analysis reveals that the signaling components of defense/stress pathways, such as methyl jasmonate (MeJA), salicylic acid (SA), gibberellic acid (GA3), and hydrogen peroxide (H2O2), up-regulate the SsPto transcript levels over the control. Nevertheless, cold treatment has no significant effect on SsPto expression, whereas SsPto expression is down-regulated by dark treatment. Our findings suggest that this novel stress- and pathogen-inducible SsPto from S. surattense may participate not only in the defense/stress responsive pathways, but also in diverse processes of plant growth and development.

Genomic cloning and characterization of a Pto-like gene SsPto-2 from Solanum surattense

A Pto-like gene (designated as SsPto-2) was isolated from Solanum surattense by using genomic walker technology which encoded a cytoplasmically localized serine-threonine protein kinase. Analysis of the 2365 bp segment revealed a gene including a 905 bp 5′ flanking region, a 924 bp open reading frame (ORF) and a 536 bp 3′ flanking region. The deduced amino acid sequence of the SsPto-2 gene shared high homology with other known Ptos. The deduced SsPto-2 protein contained no signal peptide with a calculated molecular weight of 34.61 kDa. The analysis of SsPto-2 promoter region and terminator region was also presented. Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) analysis revealed that SsPto-2 transcripts were up-regulated by defense-related factors such as gibberellic acid (GA3), salicylic acid (SA) and down-regulated by darkness. The cloning of the SsPto-2 gene will allow us to further study its potential role in disease resistance.