Doron Holland - Academia.edu (original) (raw)

Papers by Doron Holland

Planta, 2011

Anthocyanins are the major pigments responsible for the pomegranate (Punica granatum L.) fruit sk... more Anthocyanins are the major pigments responsible for the pomegranate (Punica granatum L.) fruit skin color. The high variability in fruit external color in pomegranate cultivars reXects variations in anthocyanin composition. To identify genes involved in the regulation of anthocyanin biosynthesis pathway in the pomegranate fruit skin we have isolated, expressed and characterized the pomegranate homologue of the Arabidopsis thaliana TRANSPARENT TESTA GLABRA1 (TTG1), encoding a WD40-repeat protein. The TTG1 protein is a regulator of anthocyanins and proanthocyanidins (PAs) biosynthesis in Arabidopsis, and acts by the formation of a transcriptional regulatory complex with two other regulatory proteins: bHLH and MYB. Our results reveal that the pomegranate gene, designated PgWD40, recovered the anthocyanin, PAs, trichome and seed coat mucilage phenotype in Arabidopsis ttg1 mutant. PgWD40 expression and anthocyanin composition in the skin were analyzed during pomegranate fruit development, in two accessions that diVer in skin color intensity and timing of appearance. The results indicate high positive correlation between the total cyanidin derivatives quantity (red pigments) and the expression level of PgWD40. Furthermore, strong correlation was found between the steady state levels of PgWD40 transcripts and the transcripts of pomegranate homologues of the structural genes PgDFR and PgLDOX. PgWD40, PgDFR and PgL-DOX expression also correlated with the expression of pomegranate homologues of the regulatory genes PgAn1 (bHLH) and PgAn2 (MYB). On the basis of our results we propose that PgWD40 is involved in the regulation of anthocyanin biosynthesis during pomegranate fruit development and that expression of PgWD40, PgAn1 and PgAn2 in the pomegranate fruit skin is required to regulate the expression of downstream structural genes involved in the anthocyanin biosynthesis. Keywords Anthocyanin biosynthesis • Cyanidin derivatives • Fruit development • MYB-bHLH-WD40 complex • Pomegranate • TTG1 Abbreviations bHLH Basic helix-loop-helix CHS Chalcone synthase DFR DihydroXavonol 4-reductase HPLC High performance liquid chromatography LDOX Leucoanthocyanidin dioxygenase PAs Proanthocyanidins PG Punica granatum RACE Rapid AmpliWcation of cDNA Ends TTG1 Transparent Testa Glabra1 Publication No. 129/2010 from the Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, Israel.

Journal of Experimental Botany, 1996

Horticultural Reviews, 2009

... 1984; Shulman et al. 1984; El Sese 1988; Assaf et al. 1991b; Hussein et al. 1994; Mars 2000).... more ... 1984; Shulman et al. 1984; El Sese 1988; Assaf et al. 1991b; Hussein et al. 1994; Mars 2000). In evergreen cultivars in southern India, flowering season was observed in three periods: June, October, and March (Nalwadi et al. 1973) or throughout the year (Hayes 1957). ...

Scientia Horticulturae, 2013

The vegetative and reproductive performance of 'Coscia' pear (Pyrus communis L.) grown on eight r... more The vegetative and reproductive performance of 'Coscia' pear (Pyrus communis L.) grown on eight rootstocks [OHF 217, OHF 333 and OHF 97 (USA breeding of P. communis); NY 095, NY 221, NY 36 and Lavi 1 (Israeli selections of Pyrus betulifolia) and a seedling (Davis A × B) of P. betulifolia] were compared over a 7-year period. The trial was conducted at the Experimental Orchard Farm Station in northern Israel on well-drained, pH 7.5 soil. Trees were planted in December 2005 at 4.0 m × 2.0 m spacing and trained with a central axis. The most vigorous trees were on the local and clonal P. betulifolia rootstock Lavi 1, followed by the three OHF and NY rootstocks; the P. betulifolia seedling produced the weakest tree. Tree size was positively correlated to yield and fruit size. Thus, the highest cumulative yield and cumulative yield of large fruit (>55 mm) per tree were harvested from trees on Lavi 1, followed by the two OHF rootstocks (217, 97) and NY 221. The lowest cumulative total and large-fruit yields were obtained on the P. betulifolia seedling rootstock. These results could be due to the excellent water status, e.g., the high midday stem water potential (SWP) values of 'Coscia' trees on Lavi 1 rootstocks in comparison with the other rootstocks. The positively high correlation between tree size (trunk cross-sectional area) and water status (SWP) and the similar correlation between SWP and cumulative total yield or yield of large fruit support this hypothesis. We conclude that in a warm climate, yield efficiency is not the only parameter to be taken into account; building a strong tree for a weak cultivar scion such as 'Coscia' is the first requirement for establishing an orchard. The experiments demonstrate the advantages of selecting a local clonal P. betulifolia rootstock compared to seedlings of the same species introduced from foreign countries with different climatic conditions. In addition, two genetic markers for Lavi 1 were identified based on its S-RNase alleles.

Journal of the American Society For Horticultural Science, 2005

ADDITIONAL INDEX WORDS. transposable elements, Citrus paradisi, transposon display, transformatio... more ADDITIONAL INDEX WORDS. transposable elements, Citrus paradisi, transposon display, transformation, fruit trees, genetic polymorphism ABSTRACT. The maize transposable element Activator (Ac) has been shown to be active in a number of dicots, including arabidopsis [Arabidopsis thaliana (L.) Heynh.], tobacco (Nicotiana tabacum L.), tomato (Lycopersicon esculentum Mill.), potato (Solanum tuberosum L.), and aspen (Populus tremuloides Michx.). However, no information is available on somatic transposition in any plant during several years of growth and development. It is not known how transposition affects genetic variability among vegetative parts that have developed during a long period of growth. In order to explore the possibility of using somatic Ac transposition for gene tagging and mutagenesis in fruit trees, a derivative of the maize Ac transposable element was introduced into ʻDuncanʼ grapefruit (Citrus paradisi Macf.) by Agrobacterium tumefaciens (Smith & Towns.) Conn.-mediated stable transformation. Genetically identical 4-year-old sibling trees were established by grafting one of the transformants on Troyer citrange [Citrus sinensis (L.) Osbec. x Poncirus trifoliate (L.)

Israel J Plant Sci, 2006

... in 1959 and became the main commercial al-mond cultivar grown in Israel (Barak and Adawi, 197... more ... in 1959 and became the main commercial al-mond cultivar grown in Israel (Barak and Adawi, 1971 ... 1949; Goor et al., 1966; Mouterde, 1966; http://www.ars-grin.gov/cgi-bin/npgs/html ... for almond, grapevine (Perl et al., 2000), and olive trees (Lavee, 1990), which strongly relied on ...

PLOS ONE, 2015

Color is an important determinant of pomegranate fruit quality and commercial value. To understan... more Color is an important determinant of pomegranate fruit quality and commercial value. To understand the genetic factors controlling color in pomegranate, chemical, molecular and genetic characterization of a "white" pomegranate was performed. This unique accession is lacking the typical pomegranate color rendered by anthocyanins in all tissues of the plant, including flowers, fruit (skin and arils) and leaves. Steady-state gene-expression analysis indicated that none of the analyzed "white" pomegranate tissues are able to synthesize mRNA corresponding to the PgLDOX gene (leucoanthocyanidin dioxygenase, also called ANS, anthocyanidin synthase), which is one of the central structural genes in the anthocyanin-biosynthesis pathway. HPLC analysis revealed that none of the "white" pomegranate tissues accumulate anthocyanins, whereas other flavonoids, corresponding to biochemical reactions upstream of LDOX, were present. Molecular analysis of the "white" pomegranate revealed the presence of an insertion and an SNP within the coding region of PgLDOX. It was found that the SNP does not change amino acid sequence and is not fully linked with the "white" phenotype in all pomegranate accessions from the collection. On the other hand, genotyping of pomegranate accessions from the collection and segregating populations for the "white" phenotype demonstrated its complete linkage with the insertion, inherited as a recessive single-gene trait. Taken together, the results indicate that the insertion in PgLDOX is responsible for the "white" anthocyanin-less phenotype. These data provide the first direct molecular, genetic and chemical evidence for the effect of a natural modification in the LDOX gene on color accumulation in a fruit-bearing woody perennial deciduous tree. This modification can be further utilized to elucidate the physiological role of anthocyanins in protecting the tree organs from harmful environmental conditions, such as temperature and UV radiation.

Plant Molecular Biology, Nov 1, 1994

The diurnal expression of two newly isolated genes, ccr and clr, was studied in Duncan grapefruit... more The diurnal expression of two newly isolated genes, ccr and clr, was studied in Duncan grapefruits (Citrus paradisi). The steady-state levels of mRNA corresponding to each of the genes reach their maximum at different time points during the day. The peak of ccr accumulation is at the end of the light period, while accumulation of mRNA corresponding to clr peaks already after 4-6 hours of light. The lowest steady-state levels of mRNA corresponding to both of the genes is at the dark period. ccr is highly homologous to lir1, a gene recently isolated from rice. Comparison of the deduced amino acid sequence of ccr to that deduced from lir1 indicates 49% of identity. The deduced proteins contain two imperfect repeats with two cystein residues that are positionally conserved in each of the repeats. The steady-state level of ccr transcripts continues to oscillate after the plants are transferred to darkness and displays a circadian rhythm similar to that of lir1. On the other hand, the level of clr transcripts is almost undetectable after more than 12 h in the dark. Artificial light supplement in the dark extends the length of time of clr expression during the day. clr does not show significant homology to any of the known circadian or light-regulated genes.

Medicinal and Aromatic Plants of the World, 2014

Tree Genetics & Genomes, 2013

ABSTRACT

Plant Science, 1995

A regeneration protocol.

Plant Cell, Tissue and Organ Culture, 1995

... is important because this phenomenon could be used to study genetic control of citrus ... Gen... more ... is important because this phenomenon could be used to study genetic control of citrus ... Genetic crosses between cultivars with different ability to flower precociously can be done ... experiments require more information on the infuence of various physiological and environmental ...

Perennial fruiting trees require sustained exposure to low, near freezing, temperatures before vi... more Perennial fruiting trees require sustained exposure to low, near freezing, temperatures before vigorous floral and vegetative bud break is possible after the resumption of warm temperatures in the spring. The depth of dormancy, duration of chilling required (the chilling requirement, CR) blooming date (BD) and heat requirement to break buds (HR) are determined by the climatic adaptation of the particular cultivar, thus limiting its geographic distribution. This limitation is particularly evident when attempting to introduce superior cultivars to regions with very warm winter temperatures. The physiological mechanisms for these important life history characters are partially understood however, the genetic pathways central to physiology remain poorly characterized and although breeding programs deliberately manipulate these characters, robust closely associated markers to the traits have not been available in the past. In this regard, we have developed a comprehensive mapping program...

Planta, 2011

Anthocyanins are the major pigments responsible for the pomegranate (Punica granatum L.) fruit sk... more Anthocyanins are the major pigments responsible for the pomegranate (Punica granatum L.) fruit skin color. The high variability in fruit external color in pomegranate cultivars reXects variations in anthocyanin composition. To identify genes involved in the regulation of anthocyanin biosynthesis pathway in the pomegranate fruit skin we have isolated, expressed and characterized the pomegranate homologue of the Arabidopsis thaliana TRANSPARENT TESTA GLABRA1 (TTG1), encoding a WD40-repeat protein. The TTG1 protein is a regulator of anthocyanins and proanthocyanidins (PAs) biosynthesis in Arabidopsis, and acts by the formation of a transcriptional regulatory complex with two other regulatory proteins: bHLH and MYB. Our results reveal that the pomegranate gene, designated PgWD40, recovered the anthocyanin, PAs, trichome and seed coat mucilage phenotype in Arabidopsis ttg1 mutant. PgWD40 expression and anthocyanin composition in the skin were analyzed during pomegranate fruit development, in two accessions that diVer in skin color intensity and timing of appearance. The results indicate high positive correlation between the total cyanidin derivatives quantity (red pigments) and the expression level of PgWD40. Furthermore, strong correlation was found between the steady state levels of PgWD40 transcripts and the transcripts of pomegranate homologues of the structural genes PgDFR and PgLDOX. PgWD40, PgDFR and PgL-DOX expression also correlated with the expression of pomegranate homologues of the regulatory genes PgAn1 (bHLH) and PgAn2 (MYB). On the basis of our results we propose that PgWD40 is involved in the regulation of anthocyanin biosynthesis during pomegranate fruit development and that expression of PgWD40, PgAn1 and PgAn2 in the pomegranate fruit skin is required to regulate the expression of downstream structural genes involved in the anthocyanin biosynthesis. Keywords Anthocyanin biosynthesis • Cyanidin derivatives • Fruit development • MYB-bHLH-WD40 complex • Pomegranate • TTG1 Abbreviations bHLH Basic helix-loop-helix CHS Chalcone synthase DFR DihydroXavonol 4-reductase HPLC High performance liquid chromatography LDOX Leucoanthocyanidin dioxygenase PAs Proanthocyanidins PG Punica granatum RACE Rapid AmpliWcation of cDNA Ends TTG1 Transparent Testa Glabra1 Publication No. 129/2010 from the Agricultural Research Organization (ARO), the Volcani Center, Bet Dagan, Israel.

Journal of Experimental Botany, 1996

Horticultural Reviews, 2009

... 1984; Shulman et al. 1984; El Sese 1988; Assaf et al. 1991b; Hussein et al. 1994; Mars 2000).... more ... 1984; Shulman et al. 1984; El Sese 1988; Assaf et al. 1991b; Hussein et al. 1994; Mars 2000). In evergreen cultivars in southern India, flowering season was observed in three periods: June, October, and March (Nalwadi et al. 1973) or throughout the year (Hayes 1957). ...

Scientia Horticulturae, 2013

The vegetative and reproductive performance of 'Coscia' pear (Pyrus communis L.) grown on eight r... more The vegetative and reproductive performance of 'Coscia' pear (Pyrus communis L.) grown on eight rootstocks [OHF 217, OHF 333 and OHF 97 (USA breeding of P. communis); NY 095, NY 221, NY 36 and Lavi 1 (Israeli selections of Pyrus betulifolia) and a seedling (Davis A × B) of P. betulifolia] were compared over a 7-year period. The trial was conducted at the Experimental Orchard Farm Station in northern Israel on well-drained, pH 7.5 soil. Trees were planted in December 2005 at 4.0 m × 2.0 m spacing and trained with a central axis. The most vigorous trees were on the local and clonal P. betulifolia rootstock Lavi 1, followed by the three OHF and NY rootstocks; the P. betulifolia seedling produced the weakest tree. Tree size was positively correlated to yield and fruit size. Thus, the highest cumulative yield and cumulative yield of large fruit (>55 mm) per tree were harvested from trees on Lavi 1, followed by the two OHF rootstocks (217, 97) and NY 221. The lowest cumulative total and large-fruit yields were obtained on the P. betulifolia seedling rootstock. These results could be due to the excellent water status, e.g., the high midday stem water potential (SWP) values of 'Coscia' trees on Lavi 1 rootstocks in comparison with the other rootstocks. The positively high correlation between tree size (trunk cross-sectional area) and water status (SWP) and the similar correlation between SWP and cumulative total yield or yield of large fruit support this hypothesis. We conclude that in a warm climate, yield efficiency is not the only parameter to be taken into account; building a strong tree for a weak cultivar scion such as 'Coscia' is the first requirement for establishing an orchard. The experiments demonstrate the advantages of selecting a local clonal P. betulifolia rootstock compared to seedlings of the same species introduced from foreign countries with different climatic conditions. In addition, two genetic markers for Lavi 1 were identified based on its S-RNase alleles.

Journal of the American Society For Horticultural Science, 2005

ADDITIONAL INDEX WORDS. transposable elements, Citrus paradisi, transposon display, transformatio... more ADDITIONAL INDEX WORDS. transposable elements, Citrus paradisi, transposon display, transformation, fruit trees, genetic polymorphism ABSTRACT. The maize transposable element Activator (Ac) has been shown to be active in a number of dicots, including arabidopsis [Arabidopsis thaliana (L.) Heynh.], tobacco (Nicotiana tabacum L.), tomato (Lycopersicon esculentum Mill.), potato (Solanum tuberosum L.), and aspen (Populus tremuloides Michx.). However, no information is available on somatic transposition in any plant during several years of growth and development. It is not known how transposition affects genetic variability among vegetative parts that have developed during a long period of growth. In order to explore the possibility of using somatic Ac transposition for gene tagging and mutagenesis in fruit trees, a derivative of the maize Ac transposable element was introduced into ʻDuncanʼ grapefruit (Citrus paradisi Macf.) by Agrobacterium tumefaciens (Smith & Towns.) Conn.-mediated stable transformation. Genetically identical 4-year-old sibling trees were established by grafting one of the transformants on Troyer citrange [Citrus sinensis (L.) Osbec. x Poncirus trifoliate (L.)

Israel J Plant Sci, 2006

... in 1959 and became the main commercial al-mond cultivar grown in Israel (Barak and Adawi, 197... more ... in 1959 and became the main commercial al-mond cultivar grown in Israel (Barak and Adawi, 1971 ... 1949; Goor et al., 1966; Mouterde, 1966; http://www.ars-grin.gov/cgi-bin/npgs/html ... for almond, grapevine (Perl et al., 2000), and olive trees (Lavee, 1990), which strongly relied on ...

PLOS ONE, 2015

Color is an important determinant of pomegranate fruit quality and commercial value. To understan... more Color is an important determinant of pomegranate fruit quality and commercial value. To understand the genetic factors controlling color in pomegranate, chemical, molecular and genetic characterization of a "white" pomegranate was performed. This unique accession is lacking the typical pomegranate color rendered by anthocyanins in all tissues of the plant, including flowers, fruit (skin and arils) and leaves. Steady-state gene-expression analysis indicated that none of the analyzed "white" pomegranate tissues are able to synthesize mRNA corresponding to the PgLDOX gene (leucoanthocyanidin dioxygenase, also called ANS, anthocyanidin synthase), which is one of the central structural genes in the anthocyanin-biosynthesis pathway. HPLC analysis revealed that none of the "white" pomegranate tissues accumulate anthocyanins, whereas other flavonoids, corresponding to biochemical reactions upstream of LDOX, were present. Molecular analysis of the "white" pomegranate revealed the presence of an insertion and an SNP within the coding region of PgLDOX. It was found that the SNP does not change amino acid sequence and is not fully linked with the "white" phenotype in all pomegranate accessions from the collection. On the other hand, genotyping of pomegranate accessions from the collection and segregating populations for the "white" phenotype demonstrated its complete linkage with the insertion, inherited as a recessive single-gene trait. Taken together, the results indicate that the insertion in PgLDOX is responsible for the "white" anthocyanin-less phenotype. These data provide the first direct molecular, genetic and chemical evidence for the effect of a natural modification in the LDOX gene on color accumulation in a fruit-bearing woody perennial deciduous tree. This modification can be further utilized to elucidate the physiological role of anthocyanins in protecting the tree organs from harmful environmental conditions, such as temperature and UV radiation.

Plant Molecular Biology, Nov 1, 1994

The diurnal expression of two newly isolated genes, ccr and clr, was studied in Duncan grapefruit... more The diurnal expression of two newly isolated genes, ccr and clr, was studied in Duncan grapefruits (Citrus paradisi). The steady-state levels of mRNA corresponding to each of the genes reach their maximum at different time points during the day. The peak of ccr accumulation is at the end of the light period, while accumulation of mRNA corresponding to clr peaks already after 4-6 hours of light. The lowest steady-state levels of mRNA corresponding to both of the genes is at the dark period. ccr is highly homologous to lir1, a gene recently isolated from rice. Comparison of the deduced amino acid sequence of ccr to that deduced from lir1 indicates 49% of identity. The deduced proteins contain two imperfect repeats with two cystein residues that are positionally conserved in each of the repeats. The steady-state level of ccr transcripts continues to oscillate after the plants are transferred to darkness and displays a circadian rhythm similar to that of lir1. On the other hand, the level of clr transcripts is almost undetectable after more than 12 h in the dark. Artificial light supplement in the dark extends the length of time of clr expression during the day. clr does not show significant homology to any of the known circadian or light-regulated genes.

Medicinal and Aromatic Plants of the World, 2014

Tree Genetics & Genomes, 2013

ABSTRACT

Plant Science, 1995

A regeneration protocol.

Plant Cell, Tissue and Organ Culture, 1995

... is important because this phenomenon could be used to study genetic control of citrus ... Gen... more ... is important because this phenomenon could be used to study genetic control of citrus ... Genetic crosses between cultivars with different ability to flower precociously can be done ... experiments require more information on the infuence of various physiological and environmental ...

Perennial fruiting trees require sustained exposure to low, near freezing, temperatures before vi... more Perennial fruiting trees require sustained exposure to low, near freezing, temperatures before vigorous floral and vegetative bud break is possible after the resumption of warm temperatures in the spring. The depth of dormancy, duration of chilling required (the chilling requirement, CR) blooming date (BD) and heat requirement to break buds (HR) are determined by the climatic adaptation of the particular cultivar, thus limiting its geographic distribution. This limitation is particularly evident when attempting to introduce superior cultivars to regions with very warm winter temperatures. The physiological mechanisms for these important life history characters are partially understood however, the genetic pathways central to physiology remain poorly characterized and although breeding programs deliberately manipulate these characters, robust closely associated markers to the traits have not been available in the past. In this regard, we have developed a comprehensive mapping program...