In this study,we cloned a small GTP binding protein gene(CpRAC1)by randomly sequencing from cDNA library of Chimonanthus praecox flowers. The cDNA full length of CpRAC1 gene was 1 089 bp,which contained an opening reading frame of 597 bp and encoded a protein of 198 amino acids residues. Bioinformatic analysis showed that there was no signal peptide or trans-membrane domain existed in CpRAC1 protein. Sequence alignment and phylogenetic analysis indicated that CpRAC1 protein,belonged to the typeⅠplant Rac protein,which contained the Rho superfamily conversed domain and had the high identity with other Rac proteins in different plants. The qRT-PCR demonstrated that CpRAC1 expressed in different tissues(root,stem,leaf,petal,stamen and pistil)and had the highest expression level in stamen. However,no transcripts of CpRAC1 were detected in the early stage of flower development,and then the expression level increased gradually along with the flower development. And the expression level reached its peak at the wither period. The expression of CpRAC1 was down-regulated under cold,hot,salt,CuSO4,drought and ABA stresses but up-regulated by H2O2 treatment. We speculated CpRAC1 may play impotant roles in flower development and abiotic stress response.
PrLPAAT1 gene was cloned from Paeonia rockii. The expression vector 2S2::PrLPAAT1 was constructed and transformed into wild-type(WT)Arabidposis plants by the floral dip method. Three positive T3 transformants L1OX-11,L1OX-17 and L1OX-19 were confirmed via hygromycin-resistant selection and PCR method. Semi-quantitative RT-PCR analysis indicated that PrLPAAT1 was highly expressed in transgenic Arabidopsis lines. Phenotypic analysis suggested that the seed yield had no significant changes in transgenic Arabidopsis lines,compared to WT plants. We analyzed the content and composition of FAs in mature seeds of the transgenic Arabidopsis using GC–MS. Compared with WT plants,seeds of L1OX-11,L1OX-17,and L1OX-19 line showed increased total fatty acids(FAs)content of 5.3%,and 5.2%,and the oleic acid(OA)content of 19.9%,24.6%,and 19.4%,respectively. Quantitative real-time PCR analysis indicated that a few endogenous genes(AtACP1,AtDGAT1,and AtSUS3)involved in lipid biosynthesis were up-regulated in PrLPAAT1-overexpressing lines. These results showed that PrLPAAT1 may play an important role in fatty acid biosynthesis of seed.
To investigate the growth-promoting effects and mechanisms of Bacillus amyloliquefaciens K103 on cucumber plug seedlings,K103 was inoculated into the substrate before sowing,and the growth parameters,mineral elements aborptions were measured. The rhizosphere bacterial diversities were also detected by 454 pyro sequencing. The results showed that K103 showed high nitrogen fixation and phosphorus solubilization capacity. K103 inoculation in substrate could promote the growth and development of cucumber plug seedlings by increasing the mineral absorption and root vigor. The 454 sequencing data suggested that K103 could colonize in the rhizosphere,and increase the relative abundances of nine bacteria species,including Bdellovibrio bacteriovorus,Sphingomonas sp. CHNTR37 and CL01,Acidovorax delafieldii,Mesorhizobium ciceri,etc. Most of these species were plant growth- promoting bacteria.
Chilli veinal mottle virus(ChiVMV)is one of main pathogen causing pepper virus disease in Guangdong Province,China. To ascertain the molecular characterization of ChiVMV isolate Guangdong(ChiVMV-GD),the whole genome sequence of ChiVMV-GD was cloned by RT-PCR and RACE amplification. In addition to the poly(A)tail,the length of ChiVMV-GD genome was 9 721 nt and encoded a 350.44 kD polyprotein(coordinate 167–9 436 nt). The 5′-untranslated region(5′-UTR)and 3'-untranslated region(3′-UTR)contained 166 and 285 nt,respectively. The 5′-end contained a viral genome-linked protein(VPg). The 3′-end contained a poly(A)tail. The whole genome sequence of ChiVMV-GD shared 79.1% to 96.9% nucleotide sequence identities with other isolates of ChiVMV deposited in the GenBank database,with the highest nucleotide sequence identities to the isolate Hainan(GenBank accession number:GQ981316.1)at 96.9%. Phylogenetic analysis of ChiVMV-GD and the other 11 isolates of ChiVMV indicated that it clustered with the Hainan isolate to form a unique clade. This result showed that ChiVMV-GD had the closest relationship with ChiVMV Hainan isolate. This paper is the first report the molecular characterization of ChiVMV infecting pepper in Guangdong Province,China.
Cytokinin plays an important role in the growth and development of plants,which responds to external environmental stimuli through the two-component system in plant. The response regulators (RRs)are critical members in the two-component system. Through genome-wide identification,15 putative SmRR genes were identified from the genome of Salvia miltiorrhiza. Based on conserved domains and phylogenetic analysis,15 SmRR genes were divided into two subfamilies,type-A(SmRR1–SmRR7)and type-B(SmRR8–SmRR15). Sequence analysis of the SmRR gene family in S. miltiorrhiza,including gene structure,sequence features,cis-acting element,conserved motifs,and expression in different organs,were carried out. The results showed that the REC domain contains conserved DDK amino-acid residues in type-A SmRR,type-B SmRR has conserved Myb-like domain. The exon and intron number of SmRR also has relative conservatism. The analysis of cis-regulatory elements revealed that there are many stress and growth regulating substance response elements in SmRR. Differential transcript abundance was detected for SmRRs in different organs and tissues.
Sex chromosomes,genes and MADS-box transcription factors are the key genetic factors in the development of individual or organ. In dioecism,sex chromosomes and sex determination genes determine exclusive male or female function and are the material base of heredity. Sex differentiation genes are alternatively expressed in the meristem of floral organs,which regulate the development of unisexual flower development. The ABCDE model of flower development proposes the existence of five types of gene function(A,B,C,D,and E). It turned out to be mostly genes of this model that encode members of the MADS-box family. Plant MADS-box genes regulate the timing of flower initiation and flower meristem identity,as well as various aspects of ovule,fruit,leaf,and root development. Here,we reviewed the evolutionary mechanism of plant sex chromosomes,the sex chromosomes system in horticultural plants,the localization of linkage groups of sex determination genes,the identification of genes and the research of flower development regulated by MADS-box gene family. For the future elucidation of the regulatory mechanism of sex determination in horticultural plants,numerous key topics were discussed.
In order to establish a rapid and specific detection method for tomato diseases,a quadruple PCR assay was designed for identifing the pathogens including Pseudomonas syringae pv. tomato(Pst),Clavibacter michiganensis subsp. michiganensis(Cmm),Ralstonia solanacearum(Rs)and Xanthomonas campestris pv. vesicatoria(Xcv). The specific primers(BW-F/BW-R)of Pst were designed based on the gap1 gene sequence,which can amplify 375 bp specific fragment by optimizing the PCR conditions. Besides,three pairs of specific primers of Cmm(Fan1/Fan2),Rs(RS-1-F/RS-3-R),and Xcv(XCVF/XCVR)used in this study were referenced previous studies. The primer concentration,the annealing temperature,amplification cycles,and the extension time were optimized to obtain the best ratio of primers and amplification conditions. Then,the rapid quadruple PCR detection of pathogens in tomato was established. The annealing temperature was 57.1 ℃,the extension time was 45 s and the number of cycles was 35. The final concentrations of BW-F/BW-R primers,Fan1/Fan2 primers,RS-1-F/RS-3-R primers and XCVF/XCVR primers were 0.24,0.16,0.16 and 0.08 μmol ? L-1,respectively. The expected sizes of amplification bands were 375,146,716 and 517 bp for BW-F/BW-R,Fan1/Fan2,RS-1-F/RS-3-R and XCVF/XCVR,respectively. The quadruple PCR can simultaneously detect Pst,Cmm,Rs and Xcv in infected plants tissue,with the detection limits of 0.1 ng ? μL-1 gDNA. This study indicated that quadruple PCR might be a useful tool for rapid and sensitive diagnosis and provided an effective technical support for pathogenic identification.