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Tani E.,Institute Of Agrobiotechnology Ina | Stedel C.,Agricultural University of Athens | Kalloniati C.,Agricultural University of Athens | Papaefthimiou D.,Institute Of Agrobiotechnology Ina | And 5 more authors.
Plant Physiology and Biochemistry | Year: 2011

Extensive studies on the dry fruits of the model plant arabidopsis (Arabidopsis thaliana) have revealed various gene regulators of the development and dehiscence of the siliques. Peach pericarp is analogous to the valve tissues of the arabidopsis siliques. The stone (otherwise called pit) in drupes is formed through lignification of the fruit endocarp. The lignified endocarp in peach can be susceptible to split-pit formation under certain genetic as well as environmental factors. This phenomenon delays processing of the clingstone varieties of peach and causes economical losses for the peach fruit canning industry. The FRUITFULL (FUL) and SHATTERPROOF (SHP) genes are key MADS-box transcription protein coding factors that control fruit development and dehiscence in arabidopsis by promoting the expression of basic helix-loop-helix (bHLH) transcription factors like SPATULA (SPT) and ALCATRAZ (ALC). Results from our previous studies on peach suggested that temporal regulation of PPERFUL and PPERSHP gene expression may be involved in the regulation of endocarp margin development. In the present study a PPERSPATULA-like (PPERSPT) gene was cloned and characterized. Comparative analysis of temporal regulation of PPERSPT gene expression during pit hardening in a resistant and a susceptible to split-pit variety, suggests that this gene adds one more component to the genes network that controls endocarp margins development in peach. Taking into consideration that no ALC-like genes have been identified in any dicot plant species outside the Brassicaceae family, where arabidopsis belongs, PPERSPT may have additional role(s) in peach that are fulfilled in arabidopsis by ALC. © 2011 Elsevier Masson SAS.


Pasentsis K.,Institute Of Agrobiotechnology Ina | Tsaftaris A.,Institute Of Agrobiotechnology Ina
Scientia Horticulturae | Year: 2013

Vegetable grafting is used extensively today by farmers primarily for facing soil borne problems - among other benefits - despite some unfavorable fruit quality effects observed in certain rootstock-scion combinations. Fruit shape is a characteristic known to be affected by grafting. Herein, working with pepper graftings between two pepper genotypes (cultivars) differing in fruit shape, we observed fruit shape changes after grafting the round shaped cultivar, cv. " Mytilini Round" (scion) on the long shaped cultivar, cv. " Piperaki Long" (rootstock). Furthermore, the phenotypic changes observed in scion fruits were inherited for two generations of seed derived progenies indicating that the changes imposed on scion are heritable. PCR amplifications using six inter simple sequence repeat (ISSR) primers showed that progenies developed from seeds collected from the modified scion fruits had a genetic profile more similar to the scion genetic profile and less similar to the rootstock profile indicating that only minor genetic changes occurred in the scion during grafting. The change in the fruit shape was not found to be accompanied by extended DNA sequence changes in pepper CaOvate sequence, a gene shown before to be involved in determining fruit shape in pepper, although a slight difference in CaOvate gene expression was found. Overall, understanding the molecular mechanisms that probably underline graft-induced changes paves the way to a better knowledge over the rootstock-scion interactions, the role of rootstock in scion performance and eventually the improved quality and fruit harvest from grafted vegetable plants. © 2012 Elsevier B.V.


Kapazoglou A.,Institute of Agrobiotechnology INA | Engineer C.,Institute of Agrobiotechnology INA | Drosou V.,Institute of Agrobiotechnology INA | Kalloniati C.,Agricultural University of Athens | And 7 more authors.
BMC Plant Biology | Year: 2012

Background: MADS-box genes constitute a large family of transcription factors functioning as key regulators of many processes during plant vegetative and reproductive development. Type II MADS-box genes have been intensively investigated and are mostly involved in vegetative and flowering development. A growing number of studies of Type I MADS-box genes in Arabidopsis, have assigned crucial roles for these genes in gamete and seed development and have demonstrated that a number of Type I MADS-box genes are epigenetically regulated by DNA methylation and histone modifications. However, reports on agronomically important cereals such as barley and wheat are scarce.Results: Here we report the identification and characterization of two Type I-like MADS-box genes, from barley (Hordeum vulgare), a monocot cereal crop of high agronomic importance. Protein sequence and phylogenetic analysis showed that the putative proteins are related to Type I MADS-box proteins, and classified them in a distinct cereal clade. Significant differences in gene expression among seed developmental stages and between barley cultivars with varying seed size were revealed for both genes. One of these genes was shown to be induced by the seed development- and stress-related hormones ABA and JA whereas in situ hybridizations localized the other gene to specific endosperm sub-compartments. The genomic organization of the latter has high conservation with the cereal Type I-like MADS-box homologues and the chromosomal position of both genes is close to markers associated with seed quality traits. DNA methylation differences are present in the upstream and downstream regulatory regions of the barley Type I-like MADS-box genes in two different developmental stages and in response to ABA treatment which may be associated with gene expression differences.Conclusions: Two barley MADS-box genes were studied that are related to Type I MADS-box genes. Differential expression in different seed developmental stages as well as in barley cultivars with different seed size was evidenced for both genes. The two barley Type I MADS-box genes were found to be induced by ABA and JA. DNA methylation differences in different seed developmental stages and after exogenous application of ABA is suggestive of epigenetic regulation of gene expression. The study of barley Type I-like MADS-box genes extends our investigations of gene regulation during endosperm and seed development in a monocot crop like barley. © 2012 Kapazoglou et al.; licensee BioMed Central Ltd.


Tsaballa A.,Aristotle University of Thessaloniki | Pasentsis K.,Institute Of Agrobiotechnology Ina | Darzentas N.,Institute Of Agrobiotechnology Ina | Tsaftaris A.S.,Aristotle University of Thessaloniki | Tsaftaris A.S.,Institute Of Agrobiotechnology Ina
BMC Plant Biology | Year: 2011

Background: Grafting is a widely used technique contributing to sustainable and ecological production of many vegetables, but important fruit quality characters such as taste, aroma, texture and shape are known for years to be affected by grafting in important vegetables species including pepper. From all the characters affected, fruit shape is the most easily observed and measured. From research in tomato, fruit shape is known to be controlled by many QTLs but only few of them have larger effect on fruit shape variance. In this study we used pepper cultivars with different fruit shape to study the role of a pepper Ovate-like gene, CaOvate, which encodes a negative regulator protein that brings significant changes in tomato fruit shape.Results: We successfully cloned and characterized Ovate-like genes (designated as CaOvate) from two pepper cultivars of different fruit shape, cv. "Mytilini Round" and cv. "Piperaki Long", hereafter referred to as cv. "Round" and cv. "Long" after the shape of their mature fruits. The CaOvate consensus contains a 1008-bp ORF, encodes a 335 amino-acid polypeptide, shares 63% identity with the tomato OVATE protein and exhibits high similarity with OVATE sequences from other Solanaceae species, all placed in the same protein subfamily as outlined by expert sequence analysis. No significant structural differences were detected between the CaOvate genes obtained from the two cultivars. However, relative quantitative expression analysis showed that the expression of CaOvate followed a different developmental profile between the two cultivars, being higher in cv. "Round". Furthermore, down-regulation of CaOvate through VIGS in cv. "Round" changes its fruit to a more oblong form indicating that CaOvate is indeed involved in determining fruit shape in pepper, perhaps by negatively affecting the expression of its target gene, CaGA20ox1, also studied in this work.Conclusions: Herein, we clone, characterize and study CaOvate and CaGA20ox1 genes, very likely involved in shaping pepper fruit. The oblong phenotype of the fruits in a plant of cv. "Round", where we observed a significant reduction in the expression levels of CaOvate, resembled the change in shape that takes place by grafting the round-fruited cultivar cv. "Round" onto the long-fruited pepper cultivar cv. "Long". Understanding the role of CaOvate and CaGA20ox1, as well as of other genes like Sun also involved in controlling fruit shape in Solanaceae plants like tomato, pave the way to better understand the molecular mechanisms involved in controlling fruit shape in Solanaceae plants in general, and pepper in particular, as well as the changes in fruit quality induced after grafting and perhaps the ways to mitigate them. © 2011 Tsaballa et al; licensee BioMed Central Ltd.


Tsaballa A.,Aristotle University of Thessaloniki | Pasentsis K.,Institute of Agrobiotechnology INA | Tsaftaris A.S.,Aristotle University of Thessaloniki | Tsaftaris A.S.,Institute of Agrobiotechnology INA
Plant Molecular Biology Reporter | Year: 2012

Fruit shape is a very important fruit quality character frequently affected by grafting in vegetable plants like pepper. It has already been shown that, similar to tomato, fruit shape in pepper is likely controlled by an Ovate-like gene, CaOvate, the down-regulation of which positively affects fruit elongation. To further understand the molecular mechanisms involved in pepper fruit shape control and the changes imposed by grafting, we have amplified, sequenced, and structurally characterized CaGA20ox1, the target gene of CaOvate, from a long fruit and a round fruit shaped cultivar. The results show that CaGA20ox1 has similar genomic organization to the tomato GA20ox1 and encodes a 375-amino acid polypeptide that shares 89% identity with tomato GA20ox1. We then studied CaGA20ox1 expression in different pepper plant parts and in different developmental stages of flower and fruit development. The expression of the gene was quantified by means of relative quantitative PCR in the developmental stage of 10 days after anthesis fruit of both cultivars. The results showed that there is a significant difference in the expression of the CaGA20ox1 between the two cultivars in this specific stage as well as in the expression of CaGA20ox1 after virus-induced gene silencing (VIGS) of CaOvate. Finally, the 5′ upstream sequences of CaGA20ox1 gene of the two cultivars were examined and compared. These results corroborate our previous findings, where VIGS of CaOvate alters CaGA20ox1 expression, leading to more elongated fruit, and also progress further the understanding of the genes involved in fruit shape control in pepper opening the way for understanding the molecular means of grafting effects. © 2011 Springer-Verlag.


Papaefthimiou D.,Institute of Agrobiotechnology INA | Papaefthimiou D.,Aristotle University of Thessaloniki | Tsaftaris A.S.,Institute of Agrobiotechnology INA | Tsaftaris A.S.,Aristotle University of Thessaloniki
Acta Physiologiae Plantarum | Year: 2012

Reversible histone methylations of the fourth lysine on histone 3 (H3K4) are key epigenetic marks, involved in establishing and maintaining epigenetic transcriptional states of genes during normal development and in response to environmental stresses like drought. Their dynamic regulation is modulated by a complex mechanism employing specific epigenetic factors such as histone lysine methyltransferases and the counteracting histone demethylases. The identification and characterization of such drought-responsive epigenetic factors involved in H3K4 methylation in temperate cereal crops would provide a major advantage in their breeding for higher yield. For better understanding these mechanisms and their implication in drought stress tolerance in the annual cereal crop barley (Hordeum vulgare L.), we have isolated, cloned and characterized a drought-induced PKDM7 subfamily-like H3K4 demethylase homologue, designated HvPKDM7-1. The complete cDNA clone obtained using the RCA-RACE (Rolling Circle Amplification-RACE) method, contained a 3,861 bp ORF encoding the 1,287 a. a. putative protein, which includes conserved residues compatible with the demethylation activity. Comparative genomic analysis enabled us to locate the gene on locus 3260 on the long arm of the barley chromosome 1H. Constant transcript accumulation in early barley seed development was followed by almost complete silencing, coinciding with the stage of active storage of proteins. Transcript induction by drought stress was observed in two barley cultivars and was considerably higher in the drought-tolerant cultivar, indicating that HvPKDM7-1 may be actively involved in drought tolerance control, an agronomically very important trait. © 2011 Franciszek Górski Institute of Plant Physiology, Polish Academy of Sciences, Kraków.


PubMed | Institute of Agrobiotechnology INA
Type: | Journal: BMC plant biology | Year: 2012

MADS-box genes constitute a large family of transcription factors functioning as key regulators of many processes during plant vegetative and reproductive development. Type II MADS-box genes have been intensively investigated and are mostly involved in vegetative and flowering development. A growing number of studies of Type I MADS-box genes in Arabidopsis, have assigned crucial roles for these genes in gamete and seed development and have demonstrated that a number of Type I MADS-box genes are epigenetically regulated by DNA methylation and histone modifications. However, reports on agronomically important cereals such as barley and wheat are scarce.Here we report the identification and characterization of two Type I-like MADS-box genes, from barley (Hordeum vulgare), a monocot cereal crop of high agronomic importance. Protein sequence and phylogenetic analysis showed that the putative proteins are related to Type I MADS-box proteins, and classified them in a distinct cereal clade. Significant differences in gene expression among seed developmental stages and between barley cultivars with varying seed size were revealed for both genes. One of these genes was shown to be induced by the seed development- and stress-related hormones ABA and JA whereas in situ hybridizations localized the other gene to specific endosperm sub-compartments. The genomic organization of the latter has high conservation with the cereal Type I-like MADS-box homologues and the chromosomal position of both genes is close to markers associated with seed quality traits. DNA methylation differences are present in the upstream and downstream regulatory regions of the barley Type I-like MADS-box genes in two different developmental stages and in response to ABA treatment which may be associated with gene expression differences.Two barley MADS-box genes were studied that are related to Type I MADS-box genes. Differential expression in different seed developmental stages as well as in barley cultivars with different seed size was evidenced for both genes. The two barley Type I MADS-box genes were found to be induced by ABA and JA. DNA methylation differences in different seed developmental stages and after exogenous application of ABA is suggestive of epigenetic regulation of gene expression. The study of barley Type I-like MADS-box genes extends our investigations of gene regulation during endosperm and seed development in a monocot crop like barley.

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