John M. Labavitch

University of California, Davis

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L. Carl Greve

Aarhus University

Ann L. T. Powell

University of California, Davis

Ariel R. Vicente

Consejo Nacional de Investigaciones Científicas y Técnicas

A. B. Bennett

University of California, Davis

Carl Greve

University of California, Davis

Dario Cantù

University of California, Davis

J. Adriana Sañudo‐Barajas

Centro de Investigación en Alimentación y Desarrollo

Jean S. VanderGheynst

University of Massachusetts Dartmouth

Shengke Tian

Zhejiang University

M. Huysamer

Stellenbosch University

Cooperative Institutions

University of California, Davis

225

Plant (United States)

University of California System

Cornell University

Agricultural Research Service

Centro de Investigación en Alimentación y Desarrollo

United States Department of Agriculture

University of Georgia

University of California, Berkeley

Agricultural Research Organization

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Induction and Regulation of Ethylene Biosynthesis and Ripening by Pectic Oligomers in Tomato Pericarp Discs

PLANT PHYSIOLOGY (1991)

Alan Campbell John M. Labavitch

The effect of pectic oligomers and 1-aminocyclopropane carboxylic acid on ethylene biosynthesis and color change was studied in ripening tomato pericarp discs excised from mature-green tomato fruit (Lycopersicon esculentum Mill.). Pectic oligomers induced at least four distinct responses when added to pericarp discs: (a) a short-term, transient increase in ethylene biosynthesis; (b) a long-term, persistent increase in climacteric ethylene in discs excised from mature-green fruit; (c) an advance in ripening processes, as indicated by increased reddening of the disc surfaces; and (d) a darkening of the treated endocarp surface. Pectic oligomers appear to affect the ripening of exocarp and endocarp tissues by different mechanisms. In exocarp tissues, the acceleration of reddening by pectic oligomers might simply be a consequence of induced ethylene biosynthesis. In endocarp tissues, the acceleration of reddening appears to be a direct effect of oligomers on ripening processes. We suggest that the rate of ripening of endocarp tissues may be regulated, in part, by the release of pectic oligomers from the cell walls of adjacent exocarp tissues. Exocarp and endocarp tissues of pericarp discs appear to differ in their sensitivity to ethylene at each maturity stage, and to exhibit independent changes in sensitivity to ethylene as ripening progresses. The tissue-specific pattern of reddening in tomato pericarp may result from this differential sensitivity to endogenous ethylene concentrations.

Lycopersicon

Climacteric

1-Aminocyclopropane-1-carboxylic acid

10.1104/pp.97.2.706

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Citations (53)

Cell Wall Metabolism in Ripening Fruit (VI. Effect of the Antisense Polygalacturonase Gene on Cell Wall Changes Accompanying Ripening in Transgenic Tomatoes)

PLANT PHYSIOLOGY (1993)

C. M. Sean Carrington L. Carl Greve John M. Labavitch

Cell walls of tomato (Lycopersicon esculentum Mill.) fruit, prepared so as to minimize residual hydrolytic activity and autolysis, exhibit increasing solubilization of pectins as ripening proceeds, and this process is not evident in fruit from transgenic plants with the antisense gene for polygalacturonase (PG). A comparison of activities of a number of possible cell wall hydrolases indicated that antisense fruit differ from control fruit specifically in their low PG activity. The composition of cell wall fractions of mature green fruit from transgenic and control (wild-type) plants were indistinguishable except for trans-1,2-diaminocyclohexane-N,N,N[prime],N[prime]-tetraacetic acid (CDTA)-soluble pectins of transgenic fruit, which had elevated levels of arabinose and galactose. Neutral polysaccharides and polyuronides increased in the water-soluble fraction of wild-type fruit during ripening, and this was matched by a decline in Na2CO3-soluble pectins, equal in magnitude and timing. This, together with compositional analysis showing increasing galactose, arabinose, and rhamnose in the water-soluble fraction, mirrored by a decline of these same residues in the Na2CO3-soluble pectins, suggests that the polyuronides and neutral polysaccharides solubilized by PG come from the Na2CO3-soluble fraction of the tomato cell wall. In addition to the loss of galactose from the cell wall as a result of PG activity, both antisense and control fruit exhibit an independent decline in galactose in both the CDTA-soluble and Na2CO3-soluble fractions, which may play a role in fruit softening.

Arabinose

Pectin

Genetically modified tomato

Rhamnose

Lycopersicon

10.1104/pp.103.2.429

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Citations (136)

Molecular Characterization of a Polygalacturonase Inhibitor from Pyrus communis L. cv Bartlett

PLANT PHYSIOLOGY (1993)

Henrik U. Stotz ALT. Powell S. E. Damon L. Carl Greve A. B. Bennett

A polygalacturonase inhibitor glycoprotein with an apparent molecular mass of 43 kD was purified from pear (Pyrus communis L. cv Bartlett) fruit. Chemical deglycosylation of this protein decreased the molecular mass to 34 kD. Gas chromatographic analysis suggests that N-linked glycosylation accounts for the majority of sugar moieties. Partial amino acid sequence analysis of the purified polygalacturonase inhibitor protein provided information used to amplify a corresponding cDNA by polymerase chain reactions. Multiple cloned products of these reactions were sequenced and the same open reading frame was identified in all of the products. It encodes a 36.5-kD polypeptide containing the amino acid sequences determined by protein sequencing and predicts a putative signal sequence of 24 amino acids and seven potential N-glycosylation sites. The expression of polygalacturonase inhibitor is regulated in a tissue-specific manner. Activity and mRNA level were much higher in fruit than in flowers or leaves.

Molecular mass

Pyrus communis

10.1104/pp.102.1.133

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Citations (119)

Co‐culturing Chlorella minutissima with Escherichia coli can increase neutral lipid production and improve biodiesel quality

Biotechnology and Bioengineering (2015)

Brendan T. Higgins John M. Labavitch Jean S. VanderGheynst

ABSTRACT Lipid productivity and fatty acid composition are important metrics for the production of high quality biodiesel from algae. Our previous results showed that co‐culturing the green alga Chlorella minutissima with Escherichia coli under high‐substrate mixotrophic conditions enhanced both culture growth and crude lipid content. To investigate further, we analyzed neutral lipid content and fatty acid content and composition of axenic cultures and co‐cultures produced under autotrophic and mixotrophic conditions. We found that co‐culturing C. minutissima with E. coli under high substrate conditions (10 g/L) increased neutral lipid content 1.9‐ to 3.1‐fold and fatty acid content 1.5‐ to 2.6‐fold compared to equivalent axenic C. minutissima cultures. These same co‐cultures also exhibited a significant fatty acid shift away from trienoic and toward monoenoic fatty acids thereby improving the quality of the synthesized fatty acids for biodiesel production. Further investigation suggested that E. coli facilitates substrate uptake by the algae and that the resulting growth enhancement induces a nitrogen‐limited condition. Enhanced carbon uptake coupled with nitrogen limitation is the likely cause of the observed neutral lipid accumulation and fatty acid profile changes. Biotechnol. Bioeng. 2015;112: 1801–1809. © 2015 Wiley Periodicals, Inc.

Axenic

Mixotroph

Chlorella pyrenoidosa

Scenedesmus

10.1002/bit.25609

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Citations (35)

SOME EVIDENCE ABOUT THE PHYSIOLOGICAL BASIS OF FLESH REDDENING SYMPTOMS IN PLUM FRUIT

Acta Horticulturae (2010)

George A. Manganaris Ariel R. Vicente Carlos H. Crisosto John M. Labavitch

Flesh reddening has been described as one of the manifestations of chilling injury (CI) symptoms in stone fruits, including plum, peach and nectarine fruit. Flesh reddening in peach and nectarine fruit is most evident around the pit cavity, while symptoms in plum appear initially as discoloration in the fruit flesh periphery that later is extended towards the pit cavity, covering the whole mesocarp. Intriguingly, ethylene has different effects on the incidence of flesh reddening symptoms in these phenotypically related, yet distinct species. While it is exacerbated in plums stored at 5°C under continuous ethylene exposure and is significantly reduced by 1-methylcyclopropene (1-MCP) treatments, in nectarines the opposite is true. This review study indicates that the nature of flesh reddening differs among stone fruits and suggests that in the case of plum ethylene synthesis is not merely an additional consequence of CI symptoms, it is important for the development of the disorder. Finally, the fact that flesh reddening has been observed in non-refrigerated plums during ripening after harvest suggests that flesh reddening in this fruit should be considered a general response to the stresses associated with postharvest storage and not only a CI disorder.

Flesh

10.17660/actahortic.2010.874.18

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DIRECT REGENERATION OF STRAWBERRY (FRAGARIA X ANANASSA DUCH.) FROM LEAF DISKS

Acta Horticulturae (1997)

Ellen G. Sutter Hamid Ahmadi John M. Labavitch

Fragaria

10.17660/actahortic.1997.447.52

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Citations (9)

Physiological, biochemical, and microscopic analyses of weakened walls of conidia in Colletotrichum graminicola with a disrupted class V chitin synthase gene, chsA

Physiological and Molecular Plant Pathology (2003)

Alongkorn Amnuaykanjanasin Lynn Epstein John M. Labavitch

Chitin synthase

10.1016/j.pmpp.2003.09.004

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Citations (4)

Do Cell Wall Structures Limit Xylella fastidiosa Distribution in Inoculated, Pierce's Disease Susceptible and Resistant Grapevines

John M. Labavitch Qiang Sun Steven E. Lindow Andrew Walker Hong Lin

Xylella fastidiosa

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Changes in Cell Wall Pectins Accompanying Tomato (Lycopersicon esculentum Mill.) Paste Manufacture

Journal of Agricultural and Food Chemistry (2001)

Montaña Cámara L. Carl Greve John M. Labavitch

The texture of processed tomato products is influenced by the size and solubility characteristics of soluble and particle-bound cell wall polysaccharides they contain. The acidic (pectin) polysaccharides are important contributors to texture because of their gel-forming capability and the fact that they can form aggregates. The present work describes the pectins in ripe tomato fruits and then follows changes in several classes of pectins as the fruits are subjected to hot break and the juice is subsequently concentrated to a 30 degrees Brix paste. Continued processing leads to progressive solubilization and depolymerization of polysaccharides so that the ionically and covalently bound materials that are the major pectin classes of ripe fruit are substantially reduced in amount with the concomitant increase in the more soluble water-soluble pectins of the paste product. Juice content of soluble solids ( degrees Brix) rose steadily as water content was reduced during processing. Juice content of polymeric uronic acids (i.e., pectin) also rose with concentration, but to a lesser degree than the increase in soluble solids. This indicates that processing leads to almost complete pectin depolymerization and/or the alteration of uronic acid structures so that this assay could no longer detect them. It was concluded that reductions in heat input during processing would lead to pastes with greater pectin integrity and enhanced textural characteristics.

Pectin

Depolymerization

Uronic acid

10.1021/jf010849e

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Citations (43)

Biologically-active cell wall materials

Revista Brasileira De Fisiologia Vegetal (1994)

Eunice Melotto John M. Labavitch

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Citations (2)