Antisense Acid Invertase (TIV1) Gene Alters Soluble Sugar Composition and Size in Transgenic Tomato Fruit

The project focused on a strategy to enhance tomato fruit soluble solids by evaluating components of carbohydrate metabolism in fruit of wild tomato species that accumulate sucrose rather than hexose and have extremely high soluble sugar contents. The overall goal was to determine the extent to which sucrose accumulation contributes to elevated soluble solids levels and to understand the underlying genetic and biochemical basis of the trait. The research objectives were to evaluate near isogenic L. esculentum lines segregating for sucrose- and hexose-accumulation, determine the biochemical basis of sucrose accumulation and develop molecular genetic strategies to enhance sucrose accumulation in fruit. The inheritance of the sucrose accumulation gene (sucr) was evaluated in both L. chmielewskii and L. hirsutum and shown to be conferred by a single recessive gene in each species. Stable L. esculentum lines homozygous for the sucr gene from L. chmieliewskii and L. hirsutum were well characterized on a genetic and physiological basis and have been introduced into breeding programs to modify fruit sugar composition. The metabolic basis of sucrose accumulation was determined to result from the lack of sucrose hydrolytic capacity. The invertase gene was cloned and its analysis indicated that it is transcriptionally silent in sucrose-accumulating fruit. Transgenic plants expressing an antisense invertase gene were produced and shown to accumulate high levels of sucrose, confirming the role of invertase as the primary determinant of sucrose accumulation and demonstrating the feasibility of a general strategy to genetically engineer sugar composition.

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Evaluation of transgenic tomato fruit with reduced polygalacturonase activity in combination with the rin mutation

Postharvest Biology and Technology ◽

10.1016/0925-5214(94)00049-x ◽

1995 ◽

Vol 6 (1-2) ◽

pp. 91-101 ◽

Cited By ~ 5

Author(s):

A.J. Murray ◽

C.R. Bird ◽

W.W. Schuch ◽

G.E. Hobson

Keyword(s):

Tomato Fruit ◽

Transgenic Tomato ◽

Polygalacturonase Activity

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Expression of Acid Invertase Gene Controls Sugar Composition in Tomato (Lycopersicon) Fruit

PLANT PHYSIOLOGY ◽

10.1104/pp.103.3.863 ◽

1993 ◽

Vol 103 (3) ◽

pp. 863-870 ◽

Cited By ~ 85

Author(s):

E. M. Klann ◽

R. T. Chetelat ◽

A. B. Bennett

Keyword(s):

Acid Invertase ◽

Sugar Composition ◽

Invertase Gene

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Manipulating fruit chloroplasts as a strategy to improve fruit quality

10.32747/2013.7598148.bard ◽

2013 ◽

Author(s):

Alan B. Bennett ◽

Arthur A. Schaffer ◽

Ilan Levin ◽

Marina Petreikov ◽

Adi Doron-Faigenboim

Keyword(s):

Chloroplast Development ◽

Tomato Fruit ◽

Soluble Sugar ◽

Fruit Size ◽

Soluble Solids ◽

Nucleotide Polymorphisms ◽

Ripe Fruit ◽

Green Fruit ◽

Functional Alleles ◽

Sugar Levels

The Original Objectives were modified and two were eliminated to reflect the experimental results: Objective 1 - Identify additional genetic variability in SlGLK2 and IPin wild, traditional and heirloom tomato varieties Objective 2 - Determine carbon balance and horticultural characteristics of isogenic lines expressing functional and non-functional alleles of GLKsand IP Background: The goal of the research was to understand the unique aspects of chloroplasts and photosynthesis in green fruit and the consequences of increasing the chloroplast capacity of green fruit for ripe fruit sugars, yield, flavor and nutrient qualities. By focusing on the regulation of chloroplast formation and development solely in fruit, our integrated knowledge of photosynthetic structures/organs could be broadened and the results of the work could impact the design of manipulations to optimize quality outputs for the agricultural fruit with enhanced sugars, nutrients and flavors. The project was based on the hypothesis that photosynthetic and non-photosynthetic plastid metabolism in green tomato fruit is controlled at a basal level by light for minimal energy requirements but fruit-specific genes regulate further development of robust chloroplasts in this organ. Our BARD project goals were to characterize and quantitate the photosynthesis and chloroplast derived products impacted by expression of a tomato Golden 2- like 2 transcription factor (US activities) in a diverse set of 31 heirloom tomato lines and examine the role of another potential regulator, the product of the Intense Pigment gene (IP activities). Using tomato Golden 2-like 2 and Intense Pigment, which was an undefined locus that leads to enhanced chloroplast development in green fruit, we sought to determine the benefits and costs of extensive chloroplast development in fruit prior to ripening. Major conclusions, solutions, achievements: Single nucleotide polymorphisms in the promoter, coding and intronicSlGLK2 sequences of 20 heirloom tomato lines were identified and three SlGLK2 promoter lineages were identified; two lineages also had striped fruit variants. Lines with striped fruit but no shoulders were not identified. Green fruit chlorophyll and ripe fruit soluble sugar levels were measured in 31 heirloom varieties and fruit size correlates with ripe fruit sugars but dark shoulders does not. A combination of fine mapping, recombinant generation, RNAseq expression and SNP calling all indicated that the proposed localization of a single locus IP on chr 10 was incorrect. Rather, the IP line harbored 11 separate introgressions from the S. chmielewskiparent, scattered throughout the genome. These introgressions harbored ~3% of the wild species genome and no recombinant consistently recovered the IP parental phenotype. The 11 introgressions were dissected into small combinations in segregating recombinant populations. Based on these analyses two QTL for Brix content were identified, accounting for the effect of increased Brix in the IP line. Scientific and agricultural implications: SlGLK2 sequence variation in heirloom tomato varieties has been identified and can be used to breed for differences in SlGLK2 expression and possibly in the green striped fruit phenotype. Two QTL for Brix content have been identified in the S. chmielewskiparental line and these can be used for increasing soluble solids contents in breeding programs.

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Resveratrol Biosynthesis Up-Regulates the Ascorbate/Glutathione Pathway in Transgenic Tomato Fruit

Journal of Plant Biochemistry & Physiology ◽

10.4172/2329-9029.1000105 ◽

2013 ◽

Vol 1 (2) ◽

Keyword(s):

Tomato Fruit ◽

Transgenic Tomato ◽

Glutathione Pathway

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Metabolic engineering of invertase activities in different subcellular compartments affects sucrose accumulation in sugarcane cells

Functional Plant Biology ◽

10.1071/pp00029 ◽

2000 ◽

Vol 27 (11) ◽

pp. 1021 ◽

Cited By ~ 5

Author(s):

Hongmei Ma ◽

Henrik H. Albert ◽

Robert Paull ◽

Paul H. Moore

Keyword(s):

Fold Increase ◽

Saccharum Officinarum ◽

Invertase Activity ◽

Acid Invertase ◽

Sucrose Accumulation ◽

Sugar Composition ◽

Transgenic Sugarcane ◽

Soluble Acid Invertase ◽

Invertase Gene ◽

Soluble Acid

Transgenic sugarcane (Saccharum officinarum L.) lines were created to express altered invertase isoform activity to elucidate the role(s) of invertase in the sucrose accumulation process. A sugarcane soluble acid invertase cDNA (SCINVm, AF062734) in the antisense orientation was used to decrease invertase activity. The Saccharomyces cerevisiae invertase gene (SUC2), fused with appropriate targeting elements, was used to increase invertase activity in the apoplast, cytoplasm and vacuole. A callus/liquid culture system was established to evaluate change in invertase activity and sugar concentration in the transgenic lines. Increased invertase activity in the apoplast led to rapid hydrolysis of sucrose and rapid increase of hexose in the medium. The cellular hexose content increased dramatically and the sucrose level decreased. Cells with higher cytoplasmic invertase activity did not show a significant change in the sugar composition in the medium, but did significantly reduce the sucrose content in the cells. Transformation with the sugarcane antisense acid invertase gene produced a cell line with moderate inhibition of soluble acid invertase activity and a 2-fold increase in sucrose accumulation. Overall, intracellular and extracellular sugar composition was very sensitive to the change in invertase activities. Lowering acid invertase activity increased sucrose accumulation.

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The basic helix-loop-helix transcription factor bHLH95 affects fruit ripening and multiple metabolisms in tomato

Journal of Experimental Botany ◽

10.1093/jxb/eraa363 ◽

2020 ◽

Vol 71 (20) ◽

pp. 6311-6327

Author(s):

Lincheng Zhang ◽

Jing Kang ◽

Qiaoli Xie ◽

Jun Gong ◽

Hui Shen ◽

...

Keyword(s):

Transcription Factor ◽

Fruit Ripening ◽

Tomato Fruit ◽

Soluble Sugar ◽

Glutathione Metabolism ◽

Bhlh Transcription Factor ◽

Total Carotenoids ◽

Helix Loop Helix ◽

Tomato Fruit Ripening

Abstract Ethylene signaling pathways regulate several physiological alterations that occur during tomato fruit ripening, such as changes in colour and flavour. The mechanisms underlying the transcriptional regulation of genes in these pathways remain unclear, although the role of the MADS-box transcription factor RIN has been widely reported. Here, we describe a bHLH transcription factor, SlbHLH95, whose transcripts accumulated abundantly in breaker+4 and breaker+7 fruits compared with rin (ripening inhibitor) and Nr (never ripe) mutants. Moreover, the promoter activity of SlbHLH95 was regulated by RIN in vivo. Suppression of SlbHLH95 resulted in reduced sensitivity to ethylene, decreased accumulation of total carotenoids, and lowered glutathione content, and inhibited the expression of fruit ripening- and glutathione metabolism-related genes. Conversely, up-regulation of SlbHLH95 in wild-type tomato resulted in higher sensitivity to ethylene, increased accumulation of total carotenoids, slightly premature ripening, and elevated accumulation of glutathione, soluble sugar, and starch. Notably, overexpression of SlbHLH95 in rin led to the up-regulated expression of fruit ripening-related genes (FUL1, FUL2, SAUR69, ERF4, and CNR) and multiple glutathione metabolism-related genes (GSH1, GSH2, GSTF1, and GSTF5). These results clarified that SlbHLH95 participates in the regulation of fruit ripening and affects ethylene sensitivity and multiple metabolisms targeted by RIN in tomato.

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