Differential Protein Accumulation in Banana Fruit during Ripening

6 pages, 4 figures.-- PMID: 16668607 [PubMed].-- PMCID: PMC1080163.Banana (Musa acuminata, cv Dwarf Cavendish) proteins were extracted from pulp tissue at different stages of ripening and analyzed by two-dimensional electrophoresis. The results provide evidence of differential protein accumulation during ripening. Two sets of polypeptides have been detected that increase substantially in ripe fruit. These polypeptides were characterized as glycoproteins by western blotting and concanavalin A binding assays. Antibodies againts tomato polygalacturonase cross-react with one of these sets of proteins.This work was supported by grant ALI-88-0138 from Comisión Interministerial de Ciencia y Technologia, and grant AR/88 from the Comissió Interdepartamental de Recerca e Innovació Tocnologica Generalitat de Catalunya. E.D.-P. is a recipient of a fellowship from the Ministerio Educatión y Ciencia.Peer reviewe

A cDNA clone highly expressed in ripe banana fruit shows homology to pectate lyases

6 pages, 5 figures.-- PMID: 9232883 [PubMed].-- PMCID: PMC158396.A cDNA clone (Ban17), encoding a protein homologous to pectate lyase, has been isolated from a cDNA library from climacteric banana fruit by means of differential screening. Northern analysis showed that Ban17 mRNA is first detected in early climacteric fruit, reaches a steady-state maximum at the climacteric peak, and declines thereafter in overripe fruit. Accumulation of the Ban17 transcript can be induced in green banana fruit by exogenous application of ethylene. The demonstrates that expression of this gene is under hormonal control, its induction being regulated by the rapid increase in ethylene production at the onset of ripening. The deduced amino acid sequence derived from the Ban17 cDNA shares significant identity with pectate lyases from pollen and plant pathogenic bacteria of the genus Erwinia. Similarity to bacterial pectate lyases that were proven to break down the pectic substances of the plant cell wall suggest that Ban17 might play a role in the loss of mesocarp firmness during fruit ripening.This work was supported by grant nos. ALI 91-1122-CO3-O1 and ALI 94-1031-CO3-O1 from the Comisión Interministerial de Ciencia y Tecnologia.Peer reviewe

Characterization of two divergent endo-beta-1,4-glucanase cDNA clones highly expressed in the nonclimacteric strawberry fruit

7 pages, 5 figures.-- PMID: 10198101 [PubMed].-- PMCID: PMC32027.Plant Physiol. 1999 April; 119(4): 1415–1422. PMCID: PMC32027 Copyright notice Characterization of Two Divergent Endo-β-1,4-Glucanase cDNA Clones Highly Expressed in the Nonclimacteric Strawberry Fruit Immaculada Llop-Tous, Eva Domínguez-Puigjaner, Xavier Palomer, and Miquel Vendrell* Departmento de Agrobiologia, Centro de Investigación y Desarrollo, Consejo Superior de Investigaciones Científicas, Jordi Girona, 18–26, 08034 Barcelona, Spain *Corresponding author; e-mail [email protected]; fax 34–3–204–5904. Received August 13, 1998; Accepted December 31, 1998. Small right arrow pointing to: This article has been cited by other articles in PMC. * Other Sections▼ o Abstract o MATERIALS AND METHODS o RESULTS o DISCUSSION o LITERATURE CITED Abstract Two cDNAs clones (Cel1 and Cel2) encoding divergent endo-β-1,4-glucanases (EGases) have been isolated from a cDNA library obtained from ripe strawberry (Fragaria x ananassa Duch) fruit. The analysis of the amino acid sequence suggests that Cel1 and Cel2 EGases have different secondary and tertiary structures and that they differ in the presence of potential N-glycosylation sites. By in vitro translation we show that Cel1 and Cel2 bear a functional signal peptide, the cleavage of which yields mature proteins of 52 and 60 kD, respectively. Phylogenetic analysis revealed that the Cel2 EGase diverged early in evolution from other plant EGases. Northern analysis showed that both EGases are highly expressed in fruit and that they have different temporal patterns of accumulation. The Cel2 EGase was expressed in green fruit, accumulating as the fruit turned from green to white and remaining at an elevated, constant level throughout fruit ripening. In contrast, the Cel1 transcript was not detected in green fruit and only a low level of expression was observed in white fruit. The level of Cel1 mRNA increased gradually during ripening, reaching a maximum in fully ripe fruit. The high levels of Cel1 and Cel2 mRNA in ripe fruit and their overlapping patterns of expression suggest that these EGases play an important role in softening during ripening. In addition, the early expression of Cel2 in green fruit, well before significant softening begins, suggests that the product of this gene may also be involved in processes other than fruit softening, e.g. cell wall expansion.This work was supported by grant no. ALI 98-0865 from the Comisión Interministerial de Ciencia y Tecnología and from Carburos Metálicos Sociedad Limitada.Peer reviewe

Characterization of Two Divergent Endo-β-1,4-Glucanase cDNA Clones Highly Expressed in the Nonclimacteric Strawberry Fruit

Two cDNAs clones (Cel1 and Cel2) encoding divergent endo-β-1,4-glucanases (EGases) have been isolated from a cDNA library obtained from ripe strawberry (Fragaria x ananassa Duch) fruit. The analysis of the amino acid sequence suggests that Cel1 and Cel2 EGases have different secondary and tertiary structures and that they differ in the presence of potential N-glycosylation sites. By in vitro translation we show that Cel1 and Cel2 bear a functional signal peptide, the cleavage of which yields mature proteins of 52 and 60 kD, respectively. Phylogenetic analysis revealed that the Cel2 EGase diverged early in evolution from other plant EGases. Northern analysis showed that both EGases are highly expressed in fruit and that they have different temporal patterns of accumulation. The Cel2 EGase was expressed in green fruit, accumulating as the fruit turned from green to white and remaining at an elevated, constant level throughout fruit ripening. In contrast, the Cel1 transcript was not detected in green fruit and only a low level of expression was observed in white fruit. The level of Cel1 mRNA increased gradually during ripening, reaching a maximum in fully ripe fruit. The high levels of Cel1 and Cel2 mRNA in ripe fruit and their overlapping patterns of expression suggest that these EGases play an important role in softening during ripening. In addition, the early expression of Cel2 in green fruit, well before significant softening begins, suggests that the product of this gene may also be involved in processes other than fruit softening, e.g. cell wall expansion

Maize DBF1-interactor protein 1 containing an R3H domain is a potential regulator of DBF1 activity in stress responses

The maize dehydration-responsive element (DRE)-binding factor, DBF1, is a member of the Apetala 2/Ethylene Response Factor transcription factors family and is involved in the regulation of the ABA-responsive gene rab17 through the DRE in an ABA-dependent pathway. In this study we analysed the functionality of DBF1 in abiotic stress responses and found that Arabidopsis plants over-expressing DBF1 were more tolerant to osmotic stress than control plants. In yeast two-hybrid analyses, DBF1 interacted with DBF1-interactor protein 1 (DIP1), a protein containing a conserved R3H single-strand DNA-binding domain. Subcellular localization of DIP1 showed that the protein fusion DIP1–Red Flourescent Protein (RFP) was mainly localized in the cytoplasm. However, after co-transformation of DBF1–GFP and DIP1–RFP, both proteins co-localized in the nucleus. Interestingly, when the N-terminal DBF1–GFP was co-expressed with DIP1–RFP, both proteins co-localized predominantly in the cytoplasmic speckles observed for N-terminal DBF1–GFP fusion protein. These results clearly show in vivo interaction of DBF1 with DIP1 in the cell and that this interaction is necessary for the nuclear localization of DIP1 protein. Analysis of the regulatory effect of the DBF1 and DIP1 interaction on the maize rab17 promoter activity indicated that co-transfection of DBF1 with DIP1 enhances promoter activity in the absence of ABA treatment. We suggest that the regulated association of DBF1 and DIP1 may control the levels of target gene expression during stress conditions.This work was supported by grants BIO2003-01133 from MCYT (Spain) and the ROST project QLK5-CT-2002-00841 from EU to MP. CL was supported by a Generalitat de Catalunya fellowship and ED-P by ROST.Peer reviewe