Yehiam Salts

Publications (9)30.43 Total impact

• Article: Interplay of MYB factors in differential cell expansion, and consequences for tomato fruit development

  Katja Machemer, Oxana Shaiman, Yehiam Salts, Sara Shabtai, Irina Sobolev, Eduard Belausov, Erich Grotewold, Rivka Barg
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  ABSTRACT: We previously identified SlFSM1 as an early fruit-specific gene encoding a short protein harboring a non-canonical SANT/MYB-like domain. Here, we investigated the role of FSM1 during fruit development in tomato and its mode of action. By analyzing tomato plants ectopically expressing FSM1, we established that it negatively affects cell expansion, particularly of those cells with the highest potential to expand, such as those residing inner to the vascular bundles in the fruit pericarp. This function of FSM1 differs from that of the snapdragon FSM1-like gene, RAD, which through an antagonistic activity with DIV participates in establishing floral asymmetry. Revealing an additional component of the FSM1/RAD regulatory complex, we show here that FSM1 physically interacts with FSB1, a previously uncharacterized factor harboring an atypical MYB repeat. We also demonstrate that FSB1 physically interacts with the transcription factor MYBI, a homolog of DIV. Our results show that the formation of the FSB1–MYBI complex is competed by FSM1, which recognizes in FSB1 the same region as MYBI does. Taken together, these studies expose a function for the FSM1/FSB1/MYBI complex in controlling tomato cell expansion, while revealing a mechanism by which competing MYB–MYB interactions could participate in the control of gene expression.
  The Plant Journal 08/2011; 68(2):337 - 350. · 6.16 Impact Factor
• Article: Improved yielding and reduced puffiness under extreme temperatures induced by fruit-specific expression of rolB in processing tomatoes.

  Sara Shabtai, Yehiam Salts, Galina Kaluzky, Rivka Barg
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  ABSTRACT: Tomato fruit production is severely hampered by both extremely high and low temperatures, mainly due to impaired microsporogenesis and pollination under these conditions. Even mild temperature stress, leading to partial damage to pollen viability can result in the production of under-fertilized puffy fruits of poor quality, while severe stress can abolish fruit set completely. Genetic or transgenic parthenocarpy that enables fertilization-independent fruit development offers a solution for tomato yielding under conditions unfavorable for pollen production and/or fertilization. A transgenic processing tomato UC82 line, expressing rolB specifically during early stages of fruit development was compared to the parental line with respect to yield and fruit quality under extreme temperatures. Under both high and low temperatures the transgenic line performed significantly better than the parental line. Its yield was significantly higher mainly due to a higher number of fruits that did develop, and also because of increased fruit weight. While the UC82 fruits developed under high temperatures were very puffy and severely malformed, the transgenic fruits maintained improved jelly fill and were of smooth and regular shape. Interestingly, under high temperatures the improved jelly fill in the transgenic line was accompanied by a higher number of seeds, suggesting that not only the developing seeds promote development of the placental tissue but also that proliferation of this tissue supports better seed development.
  Theoretical and Applied Genetics 06/2007; 114(7):1203-9. · 3.30 Impact Factor
• Article: Differential regulation of a fruit‐specific 62 kDa protein in developing parthenocarpic (pat‐2/pat‐2) and seeded tomato fruits

  Rivka Barg, Efrat Meir, Dvora Lapushner, Rafael Frankel, Yehiam Salts
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  ABSTRACT: The denatured protein profiles of developing tomato (Lycopersicon esculentum Mill.) fruits, from the anthesis stage up to fruits at 30% of their final diameter, were examined in a pai-2l pat-2 parthenocarpic line and in its near isogenic non-partheno-carpic line. At anthesis no differences were detected between the protein patterns of ovaries developed on parthenocarpic and non-parthenocarpic plants. In subsequent stages the seeded and seedless fruits differed in the pattern of manifestation of several abundant proteins, none of which seem to be included in seeds The most prominent difference was found in an insoluble protein of 62 kDa; in developing seeded fruits of either the parthenocarpic or the non-parthenocarpic line, its rate of decline was much faster than in seedless fruits. In seeded fruits larger than 4-6 mm in diameter it was scarcely detected, whereas in parthenocarpic seedless 8–10 mm fruits it was still abundant. This protein is fruit specific; it is also enhanced in chemically (n-n-tolyl phthalamic acid) – induced parthenocarpic fruits of the non-parthenocarpic line. The prolonged manifestation in the parthenocarpic fruits results from de novo synthesis of this protein. There are indications that it is not a stress-related protein. This is the first demonstration of an association between the pattern of modulation of a protein and the phenotypic expression of genetically controlled parthenocarpy.
  Physiologia Plantarum 04/2006; 80(3):417 - 424. · 3.11 Impact Factor
• Article: Modulated fatty acid desaturation via overexpression of two distinct omega-3 desaturases differentially alters tolerance to various abiotic stresses in transgenic tobacco cells and plants.

  Meng Zhang, Rivka Barg, Mingan Yin, Yardena Gueta-Dahan, Alicia Leikin-Frenkel, Yehiam Salts, Sara Shabtai, Gozal Ben-Hayyim
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  ABSTRACT: Changes in the degree of fatty acid (FA) desaturation are implicated in plant responses to various abiotic stresses, including heat, salt and drought. However, it is still not known whether decreased levels of linolenic acid, found in many plants subjected to salt and drought stress, reflect a mechanism of defence or damage. We addressed this question by generating tobacco cells and plants ectopically overexpressing two FA desaturases: the cytosolic FAD3 or the plastidic FAD8. A remarkable increase in the ratio of total linolenic to linoleic acids resulted from overexpression of FAD3, whereas ectopic overexpression of FAD8 induced an increased ratio mainly in the plastidic lipids. Here we present evidence that overexpressing FAD8 imposes much greater heat sensitivity than does FAD3 overexpression, in both cultured cells and whole plants. Overexpression of either FAD3 or FAD8 increases tolerance to drought in tobacco plants and to osmotic stress in cultured cells. These findings suggest that a drought-induced decreased level of linolenic acid reflects damage. Our results point to the potential of exploiting FAD overexpression as a tool to ameliorate drought tolerance.
  The Plant Journal 12/2005; 44(3):361-71. · 6.16 Impact Factor
• Article: The tomato early fruit specific gene Lefsm1 defines a novel class of plant-specific SANT/MYB domain proteins.

  Rivka Barg, Irina Sobolev, Tali Eilon, Amit Gur, Inna Chmelnitsky, Sara Shabtai, Erich Grotewold, Yehiam Salts
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  ABSTRACT: We describe here a novel plant-specific gene, Lefsm1 (fruit SANT/MYB-like 1) harboring a single SANT/MYB domain. The expression of Lefsm1 is specific to the very early stages of tomato (Lycopersicon esculentum) fruit development. Ectopic expression of Lefsm1 results in severe developmental alterations manifested in retarded growth, and reduced apical dominance during tomato and Arabidopsis seedling development. A promoter sequence residing 1.0 kb upstream to the translation initiation codon confers the organ-specific expression of the gene. Lefsm1 belongs to a novel small gene family consisting of five to six members in tomato, Arabidopsis and rice. The SANT/MYB domain of LeFSM1 and its orthologs in Arabidopsis and rice differs from that of all other plant or animal MYB proteins and from the SANT domains found in part of the chromatin remodeling proteins. Together, our results indicate that Lefsm1 is a founding member of a small family of proteins containing a novel MYB/SANT domain which is likely to participate in the regulation of a plant-specific developmental program.
  Planta 06/2005; 221(2):197-211. · 3.00 Impact Factor
• Article: Induction of parthenocarpy in tomato via specific expression of the rolB gene in the ovary.

  Nir Carmi, Yehiam Salts, Beata Dedicova, Sara Shabtai, Rivka Barg
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  ABSTRACT: The molecular signals for the development of the ovary into fruit following ovule fertilization are not clear. However, in many species, including tomato ( Lycopersicon esculentum Mill.), auxins and auxin transport inhibitors can substitute for fertilization as activators of fruit set, suggesting that this plant hormone plays a key role in this process. In agreement, transgenes for auxin biosynthesis expressed under ovary- or ovule-specific promoters were shown earlier to enable parthenocarpic (i.e. seedless) fruit development. In the present study, we tested an alternative approach for the induction of parthenocarpy that is based on ovary-specific expression of the Agrobacterium rhizogenes-derived gene rolB. This gene was chosen because rolB transgenic plants manifest several syndromes characteristic of auxin treatment. Tomato plants transformed with a chimeric construct containing the rolB gene fused to the ovary- and young-fruit-specific promoter TPRP-F1 developed parthenocarpic fruits. Fruit size and morphology, including jelly fill in the locules of the seedless fruits, were comparable to those of seeded fruits of the parental line. Although it is not known whether ROLB signals for the same cassette of genes involved in fertilization-dependent fruit development, it clearly activates a battery of genes that enable successful completion of seedless fruit development in tomato.
  Planta 10/2003; 217(5):726-35. · 3.00 Impact Factor
• Article: Isolation and preliminary characterization of tomato petal- and stamen-specific cDNAs from a subtracted and equilibrated cDNA library

  Inna Chmelnitsky, Irina Sobolev, Rivka Barg, Sara Shabtai, Yehiam Salts
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  ABSTRACT: In order to study genes involved in latestages of flower development, we wereinterested in isolating petal- orstamen-specific genes, particularly onesexpressed at a low level, as they mayinclude regulatory genes. To this end, asubtracted and equalized cDNA library oftomato petals and stamens was constructed.Approximately 650 clones of this librarywere found to represent 84 different genes.Northern analyses performed on 43 clonesdemonstrated that 19 of them are specificto stamens, five are almost exclusivelyexpressed in petals, 17 clones arespecifically expressed in both petals andstamens, two are restricted to petals andyoung fruit, and only two are non-specific.Five of the organ-specific clones, and oneof the two non-specific clones showedsimilarity to various regulatory proteins.Seventeen of the unique flower-expressedsequences were not present in either EST orGenBank databases, indicating substantialenrichment of rare transcripts. Takentogether, it was demonstrated thatfollowing careful design of subtracted andequalized cDNA library it is feasible, atreasonable time and cost, to isolate asignificant number of novel petal- and/orstamen-specific cDNA clones, even intomato, a species on which a comprehensiveEST project is currently being performed.
  Euphytica 12/2002; 129(2):229-236. · 1.55 Impact Factor
• Article: Sequence coding for a novel proline-rich protein preferentially expressed in young tomato fruit

  Yehiam Salts, Ruth Wachs, Wilhelm Gruissem, Rivka Barg
  Plant Molecular Biology 06/1991; 17(1):149-150. · 4.15 Impact Factor
• Article: LeFRK4, a novel tomato (Lycopersicon esculentum Mill.) fructokinase specifically expressed in stamens

  Marcelo A German, Nir Dai, Inna Chmelnitsky, Irina Sobolev, Yehiam Salts, Rivka Barg, Arthur A Schaffer, David Granot
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  ABSTRACT: A full-length cDNA clone encoding a novel fructokinase, LeFRK4, was isolated from a tomato (Lycopersicon esculentum Mill.) flower cDNA library. The putative protein shares 62.6 and 55.5% amino acid identity with the two known tomato fructokinases, LeFRK1 and LeFRK2, respectively, and possesses three signature patterns of the pfkB family of carbohydrate kinases, two substrate recognition sites and an ATP-binding domain. The identification of LeFRK4 as a fructokinase was confirmed by complementation of mutant yeast cells unable to phosphorylate or grow on either glucose or fructose. LeFRK4 complemented growth on fructose but not on glucose. Non-soluble crude protein extracts prepared from the transformed yeast cells exhibited fructose but not glucose phosphorylation activity. Expression analysis demonstrated that LeFRK4 is specifically expressed in stamens. Using quantitative RT-PCR, we examined the relative expression of the three known FRK genes in different tomato organs. LeFRK2, encoding a substrate-inhibited fructokinase, was by far the predominantly expressed FRK gene in all organs, except for flowers in which it shared the same expression level with LeFRK4. The exclusive expression of LeFRK4 in stamens may point to a specific role of LeFRK4 in pollen development, anthesis, and perhaps pollination.
  Plant Science.