Search

Abstract  Plants respond to cold stress by modifying the expression of a battery of cold-responsive genes. Using cDNA-AFLP techniques, GMCHI (G lycine m ax chilling-inducible) (accession no. EU699765) was isolated from the embryonic axis of a chilling-resistant cultivar of soybean seed imbibed at 4°C for 24 h. The full-length GMCHI cDNA which consisted of a single open reading frame (ORF) encoded a putative polypeptide of 129 amino acids. Sequence analysis revealed neither significant similarity of GMCHI to known proteins, nor any conserved domains found. Soybean seed imbibed at 4°C dramatically enhanced transcript level of GMCHI after 1 h, and reached a maximum at 18 h, while the expression was only detected in the embryonic axis. GMCHI expression was strongly induced by treatment with ABA and PEG, but weakly by 250 mM NaCl which suggests that GMCHI is probably regulated by ABA-dependent signal transduction pathway during cold acclimation. Overexpression of GMCHI in Arabidopsis under the control of CaMV35S promoter enhanced the tolerance to cold, drought and NaCl stresses. Therefore, GMCHI may play an important role in the adaptation of chilling-resistant soybean seed to chilling imbibition. [ABSTRACT FROM AUTHOR]

Water lily, the member of the Nymphaeaceae family, is the symbol of Buddhism and Brahmanism in India. Despite its limited researches on flower color variations and formation mechanism, water lily has background of blue flowers and displays an exceptionally wide diversity of flower colors from purple, red, blue to yellow, in nature. In this study, 34 flavonoids were identified among 35 tropical cultivars by high-performance liquid chromatography (HPLC) with photodiode array detection (DAD) and electrospray ionization mass spectrometry (ESI-MS). Among them, four anthocyanins: delphinidin 3-O-rhamnosyl- 5-O-galactoside (Dp3Rh5Ga), delphinidin 3-O-(20-O-galloyl-60"-O-oxalyl-rhamnoside) (Dp3galloyl-oxalylRh), delphinidin 3-O- (60-O-acetyl-β-glucopyranoside) (Dp3acetylG) and cyanidin 3- O-(2"0-O-galloyl-galactopyranoside)-5-O-rhamnoside (Cy3galloylGa5Rh), one chalcone: chalcononaringenin 2"-O-galactoside (Chal29Ga) and twelve flavonols: myricetin 7-O-rhamnosyl- (1→2)-rhamnoside (My7RhRh), quercetin 7-O-galactosyl-(12→)-rhamnoside (Qu7GaRh), quercetin 7-O-galactoside (Qu7Ga), kaempferol 7-O-galactosyl-(1→2)-rhamnoside (Km7GaRh), myricetin 3-O-galactoside (My3Ga), kaempferol 7-O-galloylgalactosyl-( 1→2)-rhamnoside (Km7galloylGaRh), myricetin 3-O-galloylrhamnoside (My3galloylRh), kaempferol 3-O-galactoside (Km3Ga), isorhamnetin 7-O-galactoside (Is7Ga), isorhamnetin 7-O-xyloside (Is7Xy), kaempferol 3-O-(30-acetylrhamnoside) (Km3-30acetylRh) and quercetin 3-O-acetylgalactoside (Qu3acetylGa) were identified in the petals of tropic water lily for the first time. Meanwhile a multivariate analysis was used to explore the relationship between pigments and flower color. By comparing, the cultivars which were detected delphinidin 3-galactoside (Dp3Ga) presented amaranth, and detected delphinidin 3'-galactoside (Dp3'Ga) presented blue. However, the derivatives of delphinidin and cyanidin were more complicated in red group. No anthocyanins were detected within white and yellow group. At the same time a possible flavonoid biosynthesis pathway of tropical water lily was presumed putatively. These studies will help to elucidate the evolution mechanism on the formation of flower colors and provide theoretical basis for outcross breeding and developing health care products from this plant. [ABSTRACT FROM AUTHOR]

Background Microsatellites are ubiquitous in genomes of various organisms. With the realization that they play roles in developmental and physiological processes, rather than exist as 'junk' DNA, microsatellites are receiving increasing attention. Next-generation sequencing allows acquisition of large-scale microsatellite information, and is especially useful for plants without reference genome sequences. Results In this study, enriched DNA libraries of tree peony, a well-known ornamental woody shrub, were used for high-throughput microsatellite development by 454 GS-FLX Titanium pyrosequencing. We obtained 675,221 reads with an average length of 356 bp. The total size of examined sequences was 240,672,018 bp, from which 237,134 SSRs were identified. Of these sequences, 164,043 contained SSRs, with 27% featuring more than one SSR. Interestingly, a high proportion of SSRs (43%) were present in compound formation. SSRs with repeat motifs of 1-4 bp (mono-, di-, tri-, and tetra-nucleotide repeats) accounted for 99.8% of SSRs. Di-nucleotide repeats were the most abundant. As in most plants, the predominant motif in tree peony was (A/T)n, with (G/C)n less common. The lengths of SSRs were classified into 11 groups. The shortest SSRs (10 bp) represented 1% of the total number, whereas SSRs 21-30 and 101-110 bp long accounted for 26% and 29%, respectively, of all SSRs. Many sequences (42,111) were mapped to CDS (coding domain sequence) regions using Arabidopsis as a reference. GO annotation analysis predicted that CDSs with SSRs performed various functions associated with cellular components, molecular functions, and biological processes. Of 100 validated primer pairs, 24 were selected for polymorphism analysis among 23 genotypes; cluster analysis of the resulting data grouped genotypes according to known relationships, confirming the usefulness of the developed SSR markers. Conclusions The results of our large-scale SSR marker development using tree peony are valuable for investigating plant genomic structural evolution and elucidating phenotypic variation in this species during its evolution and artificial selection. The newly identified SSRs should be useful for genetic linkage map construction, QTL mapping, gene location and cloning, and molecular marker-assisted breeding. In addition, the genome-wide marker resources generated in this study should aid genomic studies of tree peony and related species. [ABSTRACT FROM AUTHOR]