IiSDD1, a gene responsive to autopolyploidy and environmental factors in Isatis indigotica.
ABSTRACT In plants, stomata play a pivotal role in the regulation of gas exchange and are distributed throughout the aerial epidermis. SDD1, a gene isolated from Arabidopsis thaliana has been demonstrated to specialize in stomatal density and distribution. In our present study, a comprehensive survey of global gene expression performed by using an A. thaliana whole genome Affymetrix gene chip revealed SDD1 tends to be significantly lower in tetraploid Isatis indigotica than in diploid ones. To intensively investigate different SDD1 expression in response to polyploidy, a full-length cDNA clone (IiSDD1) encoding SDD1 was isolated from the traditional Chinese medicinal herb I. indigotica cDNA library. IiSDD1 shared a high level of identity with that from A. thaliana, containing some basic features of subtilases: D, H and S regions, as well as a substrate-binding site. Real-time quantitative PCR analysis indicated that IiSDD1 was constitutively expressed in all tested tissues, including roots, stems and leaves, both in tetraploid and diploid I. indigotica, and with the highest expression in leaves. In addition, IiSDD1 was also found to be down-regulated by signalling molecules for plant defence responses, such as abscisic acid (100 microM) and gibberellin (100 mg/L), as well as by environmental stresses including salt, darkness, coldness and drought. Our study, for the first time, indicates SDD1 participates not only in the defense/stress responsive pathways, but also probably involves in plants polyploidy evolution.
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ABSTRACT: This study analyzed the differences in karyotype and genetic variation between a mutant and wild-type Siraitia grosvenorii. Genetic variation included changes in genome and gene expression by SRAP molecular markers. Results showed that wild-type S. grosvenorii was diploid, with a chromosome number of 2n = 2x = 28, whereas the mutant was tetraploid with a chromosome number of 2n = 4x = 56. 4573 DNA bands were obtained using 189 different primer combinations, 577 of which were polymorphic, averaging 3.1 bands for each primer pair, while 1998 pairs were identical. There were no apparent differences on bands amplified by most primer pairs. After comparing the diploid and tetraploid strains, the data generally indicated that the polymorphism would be quite low. 2917 cDNA bands were generated using 133 primer combinations, and stable and clearly differential fragments were sorted out, cloned and sequenced. Ninety-two differentially expressed fragments were successfully sequenced. Sequence analysis showed that most fragments had significant homologous nucleotide sequences with resistant to stress and photosynthesis genes, including ribulose-1,5-bisphosphate carboxylase/oxygenase, phosphoenolpyruvate carboxykinase, pyruvate kinase, peroxisomal membrane transporter, NBS-LRR type resistance protein, protein phosphatase and others. The results revealed that the tetraploid strain has more resistant and photosynthesis ability than its diploid relatives, which providing reference information and resources for molecular breeding and seedless Luohanguo.Molecular Biology Reports 05/2011; 39(2):1247-52. · 2.51 Impact Factor
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ABSTRACT: Trichoderma asperellum, a filamentous soil fungus, is an effective biocontrol agent against many fungal plant pathogenic species. In the present study, we investigated the biological control properties of the strain T. asperellum T4. T. asperellum fermentation products significantly decreased the ability of Rhizoctonia solani and Sclerotinia sclerotiorum to infect rice and soybean, respectively. To further elucidate the biocontrol mechanisms of T. asperellum at the molecular level, a cDNA library was constructed from its mycelium. In total, 3114 expressed sequence tags (ESTs) were generated, which represented 1,554 unigenes, including 354 contigs and 1,200 singletons. Among these unigenes, 731 represented known genes while 823 were novel genes. Forty-six unigenes potentially involved in biocontrol processes were identified from the EST collection. Among them, the expressions of 16 genes were studied, and 15 genes were highly differentially regulated during confrontation with 2 phytopathogens, suggesting that they play roles in the T. asperellum response to phytopathogens. Our study may provide helpful insight in the mechanism of biocontrol by T. asperellum T4 against plant pathogens.Molecular Biology Reports 03/2010; 37(8):3673-81. · 2.51 Impact Factor
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ABSTRACT: A novel cinnamoyl-CoA reductase gene, designated as Iiccr (GenBank Accession No. GQ872418) was cloned from Isatis indigotica Fort. The full-length cDNA of Iiccr was 1368 bp with an ORF of 1026 bp that putatively encoded a polypeptide of 341 amino acids, with a predicted molecular mass of 37.50 kDa. The deduced amino acid sequence of IiCCR shared high homology with other known CCRs. No intron was detected in the genomic sequence of Iiccr. Southern-blot analysis revealed that Iiccr was a high-copy gene and real-time quantitative PCR analysis indicated that Iiccr was constitutively expressed in roots, stems and leaves of I. indigotica, with the highest expression level in roots. The results from treatment experiments using different signaling components for plant defense responses including methyl jasmonate (MeJA), gibberellins (GA(3)), abscisic acid (ABA) and ultraviolet-B revealed that expression of IiCCR had a prominent diversity. The full-length of ORF was sub-cloned into prokaryotic expression vector pET32a(+), which was then transferred into E. coli BL21(DE3). The recombinant protein had high expression level in E. coli BL21(DE3) with IPTG induction. A 2.6 kb long promoter sequence was isolated and its putative regulatory elements and potential specific transcription factor binding sites were analyzed. This study will enable us to further understand the role of IiCCR in the synthesis of phenylpropanoid compounds in I. indigotica Fort. at the molecular level.Molecular Biology Reports 03/2011; 38(3):2075-83. · 2.51 Impact Factor