Article

Isolation and characterization of floral transcripts from mangosteen (Garcinia mangostana L.)

Trees (Impact Factor: 1.93). 23(5):899-910. DOI: 10.1007/s00468-009-0331-2

ABSTRACT The understanding of flower initiation, development, and maturation in mangosteen is of paramount importance to shorten its
long juvenile phase and to synchronize its flowering or fruiting time. In this study, we have identified 97 tentative unique
genes with higher expression levels in young flower buds compared to young shoots by using suppressive subtraction hybridization
and reverse northern analysis. Sequence analysis showed that 63.9% of these transcripts had non-significant matches to sequences
in the non-redundant protein database in GenBank, 19.6% had significant matches to unknown proteins while the remaining 16.5%
had putative functions in transcription, stress, signal transduction, cell wall biogenesis, photosynthesis and miscellaneous.
The full-length cDNA of GmAGMBP encoding AG-motif binding protein (a zinc finger transcriptional factor), and 3′ termini cDNA
sequences of GmHSA32 and GmBZIP, encoding heat-stress-associated 32 (HSA32) and bZIP transcription factor, respectively; were
cloned and further analysed. Real-time PCR analysis revealed that these three genes have different transcript profiles in
flowers of different developmental stages and young shoots. The highest abundance of transcripts was achieved in flowers with
diameters ranging from 0.5 to 0.9cm for GmAGMBP and GmBZIP and in flowers with diameters less than 0.5cm for GmHSA32. Southern
analysis suggested that GmAGMBP might be single copy gene while GmHSA3A could possibly belong to a small gene family in the
mangosteen genome.

0 Bookmarks
 · 
93 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The 70-kD heat shock proteins (Hsp70s) have been shown to be important for protein folding, protein translocation, and stress responses in almost all organisms and in almost all subcellular compartments. However, the function of plastid stromal Hsp70s in higher plants is still uncertain. Genomic surveys have revealed that there are two putative stromal Hsp70s in Arabidopsis thaliana, denoted cpHsc70-1 (At4g24280) and cpHsc70-2 (At5g49910). In this study, we show that cpHsc70-1 and cpHsc70-2 could indeed be imported into the chloroplast stroma. Their corresponding T-DNA insertion knockout mutants were isolated and designated as Deltacphsc70-1 and Deltacphsc70-2. No visible phenotype was observed in the Deltacphsc70-2 mutant under normal growth conditions. In contrast, Deltacphsc70-1 mutant plants exhibited variegated cotyledons, malformed leaves, growth retardation, and impaired root growth, even though the protein level of cpHsc70-2 was up-regulated in the Deltacphsc70-1 mutant. After heat shock treatment of germinating seeds, root growth from Deltacphsc70-1 seeds was further impaired, indicating that cpHsc70-1 is important for thermotolerance of germinating seeds. No Deltacphsc70-1 Deltacphsc70-2 double mutant could be obtained, suggesting that the Deltacphsc70 double knockout was lethal. Genotype analyses of F(1) seedlings from various crosses indicated that double-knockout mutation was lethal to the female gametes and reduced the transmission efficiency of the male gametes. These results indicate that cpHsc70s are essential for plant development and the two cpHsc70s most likely have redundant but also distinct functions.
    Plant physiology 04/2008; 146(3):1231-41. · 6.56 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We have previously cloned a gene for a zinc finger protein (EPF1) that is expressed specifically in petals and interacts with the promoter region of the 5-enolpyruvylshikimate-3-phosphate synthase gene in petunia. In an attempt to isolate genes encoding additional factors that interact with this promoter, we cloned four novel genes encoding zinc finger proteins (EPF2-5a, EPF2-5b, EPF2-4, and EPF2-7). Sequence analyses revealed that overall similarity between the EPF1 and the EPF2 protein family, except in the zinc finger motifs and the basic amino acid cluster, was very low, suggesting that the two groups belong to different subfamilies. DNA binding specificities of EPF1, EPF2-5, and EPF2-4 were very similar, as expected from the conserved zinc finger motifs. However, EPF2-7 showed no binding to the probes tested in spite of having the conserved motifs. DNA binding studies using a series of spacing mutant probes suggested a binding mechanism in which the EPF proteins recognize spacings in target DNA. RNA gel blot analyses and histochemical analyses with a promoter and beta-glucuronidase fusion revealed that expression of the EPF2-5 gene (EPF2-5) was petal and stamen specific. Expression of the EPF2-7 gene (EPF2-7) was sepal and petal specific and localized in vascular tissues. The preferential expression in two adjacent floral organs raises the possibility that these genes are downstream transcription factors of floral homeotic genes.
    The Plant Cell 08/1994; 6(7):947-58. · 9.25 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The vegetative and reproductive (flowering) phases of Arabidopsis development are clearly separated. The onset of flowering is promoted by long photoperiods, but the constans (co) mutant flowers later than wild type under these conditions. The CO gene was isolated, and two zinc fingers that show a similar spacing of cysteines, but little direct homology, to members of the GATA1 family were identified in the amino acid sequence. co mutations were shown to affect amino acids that are conserved in both fingers. Some transgenic plants containing extra copies of CO flowered earlier than wild type, suggesting that CO activity is limiting on flowering time. Double mutants were constructed containing co and mutations affecting gibberellic acid responses, meristem identity, or phytochrome function, and their phenotypes suggested a model for the role of CO in promoting flowering.
    Cell 04/1995; 80(6):847-57. · 31.96 Impact Factor