Search Results

You are looking at 1 - 10 of 134 items for :

  • "polygalacturonase" x
  • Refine by Access: All x
Clear All
Free access

Russell Pressey

Polygalacturonase (PG) in higher plants has been considered to be associated with ripening fruits although it is now known to be present in foliage and storage organs. We recently found very high levels of PG in some grass pollens (Plant Science 59, 57-62, 1989). This prompted an examination of other pollens for PG activity. All of the pollens analyzed contained PG but the range of activities was great. Eastern cottonwood pollen contained the most PG, with a level about 12 times higher than that usually found in ripe tomato fruit. Pollens from the other members of Populus were generally high in PG. Pollens from the oak family also contained very high PG, with the highest amount in white oak pollen. Pollens from pecan, English walnut, willows, birch and hickories contained moderate levels of PG. The lowest amounts of PG were found in pollens from beech, sycamore and conifers. The PG's from the two richest sources (eastern cottonwood and white oak pollens) were partially purified and characterized. Both enzymes were found to be exopolygalacturonases that require Ca2+ for activity. PG may be involved in some function related to pollination but an explanation for the wide range of activities indifferent pollen is not obvious.

Free access

Russell Pressey

Polygalacturonase (PG) in higher plants has been considered to be associated with ripening fruits although it is now known to be present in foliage and storage organs. We recently found very high levels of PG in some grass pollens (Plant Science 59, 57-62, 1989). This prompted an examination of other pollens for PG activity. All of the pollens analyzed contained PG but the range of activities was great. Eastern cottonwood pollen contained the most PG, with a level about 12 times higher than that usually found in ripe tomato fruit. Pollens from the other members of Populus were generally high in PG. Pollens from the oak family also contained very high PG, with the highest amount in white oak pollen. Pollens from pecan, English walnut, willows, birch and hickories contained moderate levels of PG. The lowest amounts of PG were found in pollens from beech, sycamore and conifers. The PG's from the two richest sources (eastern cottonwood and white oak pollens) were partially purified and characterized. Both enzymes were found to be exopolygalacturonases that require Ca2+ for activity. PG may be involved in some function related to pollination but an explanation for the wide range of activities indifferent pollen is not obvious.

Free access

Elysia K. Krieger, Edwards Allen, Larry A. Gilbertson, James K. Roberts, William Hiatt, and Rick A. Sanders

The Flavr Savr tomato has increased storage life through suppression of the tomato polygalacturonase ( PG ) gene, resulting from transformation of an antisense expression cassette of the PG cDNA (pCGN1436) ( Sheehy et al., 1988 ). Efficacious

Free access

H. Yoshioka, K. Aoba, and Y. Kashimura

Abbreviation: PG, polygalacturonase. This paper is contribution no. C-161 of Fruit Tree Research Station. We thank T. Kubota and his staff, National Farmers' Academy of Deciduous Fruit Trees Training Center, for kindly providing the pears and T

Free access

Henrik Stotz, Ann Powell, Susan Damon, Audrey Hentzen, Carl Greve, Alan Bennett, and John Labavitch

Higher plant inhibitors of fungal polygalacturonases are potential contributors to plant defense. To test this hypothesis we have raised antibodies against the `Bartlett' pear fruit polygalacturonase inhibitor (PGIP) and cloned a pear fruit PGIP cDNA. The pear PGIP cDNA was isolated by polymerase chain reactions based on our amino acid and nucleotide sequence information. Sequence analysis predicts a gene product of 34.5 kD with an isoelectric point of 6.02 in agreement with our biochemical data. Seven potential glycosylation sites are consistent with the glycoprotein character of these PGIPs. Southern blot analysis suggests the presence of 1 or 2 genes in the pear genome. Northern blot analysis indicates the presence of a transcript of 1.5 kb. Western blot analysis shows cross-reactivity of the anti-pear PGIP antibody to various dicot species as well as corn.

Free access

Russell Pressey and Richard B. Russell

Polygalacturonase inhibitors have been reported in a number of dicotyledonous plant tissues including pear and raspberry fruits and bean seedlings. These proteins inhibit fungal polygalacturonases and thus have been implicated in disease resistance in plants. The earlier work on the inhibitor from bean plants was conducted with hypocotyls as the source. We have found that immature bean pods contain much more inhibitor than other parts of the plant and developed a procedure for purification of this inhibitor. Fresh bean pods were extracted with 1.0 M NaCl at pH 7 and the proteins were precipitated with ammonium sulfate. The proteins were dissolved, dialyzed and chromatographed on a column of S-Sepharose. The inhibitor from this step was then chromatographed on a Mono Q column at high pH. Yields of the inhibitor varied somewhat with bean cultivar and pod maturity but were about ten times higher than from hypocotyls. The purified inhibitor reacted optimally with Aspergillus niger endopolygalacturonase at pH 4.3 and appeared to be similar to the inhibitor from hypocotyls. Bean pods thus are a convenient source of polygalacturonase inhibitor for studies on fruit maturation and disease resistance in plants.

Free access

Andrew Proctor and Terrence J. Miesle

Polygalacturonase (PG, E.C. 3.2.1.15) and pectinmethylesterase (PME, E.C. 3.1.1.11) activities, berry size, and texture were measured in fruit of developing high-bush blueberries (Vaccinium corymbosum L.). Peak PME activity occurred in red berries and preceded peak PG activity, which was observed in blue-red fruit. Extensive softening occurred with the transition in berry color from red to blue-red. Both peak enzyme activities and maximum softening occurred by the time the fruit were =70$%0 of their maximum fresh weight.

Free access

Seung-Ryeul Shin, Jae-Kyun Byun, and Kyung-Ho Chang

Polygalacturonase (PG) was purified from apple, Malus domestica Borkh, cv. Fuji by gel filtration, CM cellulose ion exchange column chromatography and characterized by means of several biochemical methods. Two forms of isozymes, PG-I and PG-II, were detected and the activities of PG-I were found to be higher than PG-II. The Km and Vmax values were calculated to be 1.54 mg/ml and 0.25 μM with reducing sugar 1 ml/30min., respectively. The PG was active between pH 3 and 8 with the optimum pH of about 4-5. The stable temperature for the PG was below 55°C with 30°C optimum. The PG activities were increased by Na* and Cu**, but were inhibited by Ag*, EDTA and SDS.

Free access

Ming-Wei S. Kao, Jeffrey K. Brecht, Jeffrey G. Williamson, and Donald J. Huber

Crisosto, 2005 ; Robertson et al., 1990 ). Textural changes during peach fruit ripening are achieved by the concerted action of several cell wall modification enzymes ( Brummell et al., 2004 ; Hadfield and Bennett, 1998 ). Endo-polygalacturonase [endo

Free access

Zhengke Zhang, Zhaoyin Gao, Min Li, Meijiao Hu, Hui Gao, Dongping Yang, and Bo Yang

et al., 2005 ), banana ( Promyou et al., 2008 ) and citrus ( Bassal and EI-Hamahmy, 2011 ). Heat air treatment (38 °C, 3 d) may accelerate the softening that related to changes in pectic components and activities of polygalacturonase (PG), pectin