scholarly journals PHENOLIC METABOLISM AND INTERNAL BREAKDOWN (CHILLING INJURY) OF PEACH FRUIT

HortScience ◽  
1990 ◽  
Vol 25 (11) ◽  
pp. 1356H-1357 ◽  
Author(s):  
Hendrik van Gorsel ◽  
Adel A. Kader
Keyword(s):  
Phenolic Compounds ◽  
Phenylalanine Ammonia Lyase ◽  
Chilling Injury ◽  
Limiting Factor ◽  
Stone Fruits ◽  
Peach Fruit ◽  
Phenolic Metabolism ◽  
Pal Activity ◽  
Postharvest Handling ◽  
Chilling Temperatures

Internal breakdown (IB) is the limiting factor in the storage and postharvest handling of stone fruits. The symptoms of IB appear when fruits are kept for prolonged periods at temperatures below 10C and include leatheriness, mealiness, browning and bleeding of the flesh, and failure to ripen normally. We investigated the changes in phenolic compounds associated with IB of stone fruits. Twenty-eight phenolic compounds were separated by HPLC. Ten of these components were significantly affected by chilling temperatures. The concentration of six phenols changed in response to ripening after chilling temperatures, parallel to the appearance of IB symptoms. Most phenols showed a concentration gradient from the inside to the outside of the fruit, Comparison between peach cultivars showed characteristic differences in phenol metabolism during ripening. In both cultivars the most predominant phenol, chlorogenic acid, showed little change in concentration during storage. The structure of key phenolic compounds will be determined in order to elucidate the biochemical relationship between the phenols and the related enzymes. In this respect, a method was developed to detect phenylalanine ammonia-lyase (PAL) activity in peach fruit.

scholarly journals Phenylalanine Ammonia-lyase Inhibitors Do Not Prevent Russet Spotting Lesion Development in Lettuce Midribs

1998 ◽  
Vol 123 (4) ◽  
pp. 687-691 ◽  
Author(s):  
Galen Peiser ◽  
Gloria López-Gálvez ◽  
Marita Cantwell ◽  
Mikal E. Saltveit
Keyword(s):  
Phenolic Compounds ◽  
Phenylalanine Ammonia Lyase ◽  
Phenylpropanoid Pathway ◽  
Aminooxyacetic Acid ◽  
Physiological Disorder ◽  
Phenolic Metabolism ◽  
Pal Activity ◽  
Iceberg Lettuce ◽  
Tartaric Acids ◽  
Lyase Activity

Russet spotting is a physiological disorder of lettuce (Lactuca sativa L.) caused by exposure to hormonal levels (<1 μL·L-1) of ethylene in air at ≈5 °C. Enhanced phenolic metabolism and the accumulation of phenolic compounds accompany the appearance of brown, oval lesions on the leaf midrib. Phenylalanine ammonia-lyase (PAL) is the first committed enzyme in the phenylpropanoid pathway. Three inhibitors of PAL activity [2-aminoindan-2-phosphonic acid (AIP), α-aminooxyacetic acid (AOA), and α-aminooxi-β-phenylpropionic acid (AOPP)] greatly reduced the accumulation of phenolic compounds and browning of lesions. At a concentration of 50 μm, AIP inhibited the formation of chlorogenic and dicaffeoyl tartaric acids in cut midribs of iceberg lettuce by 92% and 98%, respectively. AIP competitively inhibited PAL activity from a lettuce midrib homogenate with an apparent Ki of 22 nm. While the formation of phenolic compounds was strongly inhibited by AIP, the number of lesions associated with russet spotting was not affected. Only the color of the lesions was affected by AIP. In control midribs the russet spotting lesions were brown while those in the AIP-treated midribs were initially olive green and after 3 to 7 days these lesions turned the characteristic brown color. No tyrosine ammonia-lyase activity was detected in a homogenate of lettuce midrib tissue. These results indicate that the early development of russet spotting lesions is independent of the increase in PAL activity and phenolic compounds rather than an effect of these increases as previously suggested. However, accumulation of phenolic compounds does contribute to the subsequent browning symptoms indicative of russet spotting.

scholarly journals Monitoring of the PAL Enzymatic Activity and Polyphenolic Compounds in Leaves and Fruits of Two Myrtle Cultivars during Maturation

Agriculture ◽  
2020 ◽  
Vol 10 (9) ◽  
pp. 389
Author(s):  
Silvia Medda ◽  
Leonarda Dessena ◽  
Maurizio Mulas
Keyword(s):  
Phenolic Compounds ◽  
Phenylalanine Ammonia Lyase ◽  
Raw Materials ◽  
Phenylpropanoid Pathway ◽  
Polyphenolic Compounds ◽  
Antioxidant Compounds ◽  
Total Polyphenols ◽  
Spectrophotometric Methods ◽  
Pal Activity ◽  
Potential Use

The leaves and berries of myrtle (Myrtus communis L.) are rich in phenolic compounds, such as phenolic acids, flavonoids, and flavanols. The richness of these antioxidant compounds allows the potential use of myrtle biomasses as raw materials for medicinal and functional food products. Most of the phenolic compounds originate from the phenylpropanoid pathway, where phenylalanine ammonia lyase (PAL) enzyme activates the first step. The objective of this research is to study the activity of PAL as related to accumulation in the myrtle fruits and leaves of some phenolic compounds in the period between blossom and full berry ripening. With this aim, we compared two model genotypes with different fruit coloration. In leaves and berries of two cultivars, ‘Giovanna’ with pigmented berries and ‘Grazia’ with white berries, the PAL activity and content of polyphenols, anthocyanins, flavonoids, and tannins were determined with spectrophotometric methods. PAL activity was quite constant in leaves and variable in berries: Greater in berries of ‘Giovanna’ than in those of ‘Grazia’ cultivar, and increasing from berry color-break to full ripening. In berries, a positive correlation between PAL and flavonoids (r = 0.44), and between PAL and anthocyanins (r = 0.69), as well as a negative correlation between PAL and total polyphenols (r = −0.471), were found.

Acifluorfen Action on Growth and Phenolic Metabolism in Soybean (Glycine max) Seedlings

Weed Science ◽  
1989 ◽  
Vol 37 (6) ◽  
pp. 743-747 ◽  
Author(s):  
Robert E. Hoagland
Keyword(s):  
Glycine Max ◽  
Chlorophyll A ◽  
Root Elongation ◽  
Liquid Culture ◽  
Phenylalanine Ammonia Lyase ◽  
Hypocotyl Length ◽  
Phenolic Metabolism ◽  
Soybean Seedlings ◽  
Pal Activity ◽  
Chlorophyll Accumulation

Three-day-old soybean seedlings were treated with acifluorfen via liquid culture [50 μM in dark, 1 μM in light (200 μE·m–2·s–1)]. Root elongation in the dark was inhibited only slightly (6%) after 96 h. In the light, acifluorfen inhibited root elongation after 48 h; after 96 h, inhibition was 32%. Hypocotyl length was not affected in either the light or dark. Soluble hydroxyphenolic content per axis was unaffected in the dark but was reduced by about 13 to 25% at 24 to 96 h in the light. Extractable phenylalanine ammonia-lyase (PAL, EC 4.3.1.5) activity per axis was unaltered by herbicide in the dark. A brief transient increase in PAL activity (4 to 24 h) in axes of light-grown seedlings in the presence of acifluorfen was followed by reduced enzyme levels compared to light-grown controls at 72 and 96 h. Although light is required for maximal herbicide action, there was no effect on anthocyanin or chlorophyll accumulation or on the chlorophyll a/b ratio in hypocotyls or light-grown seedlings.

scholarly journals Induction of Chitinase, β-1,3-Glucanase, and Phenylalanine Ammonia Lyase in Peach Fruit by UV-C Treatment

2003 ◽  
Vol 93 (3) ◽  
pp. 349-355 ◽  
Author(s):  
Ahmed El Ghaouth ◽  
Charles L. Wilson ◽  
Ann M. Callahan
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Defense Responses ◽  
Peach Fruit ◽  
Rapid Induction ◽  
Pal Activity ◽  
Induction Kinetic ◽  
Elicitor Treatment ◽  
Kinetic Pattern ◽  
A Minor ◽  
Uv C

Treatment of peach fruit with UV-C light caused a rapid induction of chitinase, β-1,3-glucanase, and phenylalanine ammonia lyase (PAL) activities starting 6 h after treatment and reaching maximum levels at 96 h after treatment. By 96 h after UV-C treatment, chitinase, β-1,3-glucanase, and PAL activities in UV-C-treated fruit were over twofold above the levels observed for the control. In nontreated control fruit, no apparent increase in chitinase and β-1,3-glucanase activities was detected but a minor increase in PAL activity was seen. The transient increase in chitinase, β-1,3-glucanase, and PAL activities in UV-C-treated fruit was preceded by a gradual activation of the corresponding genes. UV-C-treated fruit showed an increase in accumulation of β-1,3-glucanase and chitinase mRNAs at 3 h after treatment, which peaked approximately 96 h posttreatment. A similar induction kinetic pattern was observed for PAL mRNA in response to UV-C treatment, except the induction started 6 h after UV-C treatment. These results show that the response of peach fruit to elicitor treatment is similar to that seen in other plant-elicitors interactions and suggests the involvement of peach biochemical defense responses in UV-C-mediated disease resistance.

scholarly journals Activity of Cell Wall-associated Enzymes in Cold-stored Tomato Fruit

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1131A-1131
Author(s):  
A. Rugkong ◽  
J.K.C. Rose ◽  
C.B. Watkins
Keyword(s):  
Cell Wall ◽  
Color Change ◽  
Tomato Fruit ◽  
Chilling Injury ◽  
Pectin Methylesterase ◽  
Chilling Temperature ◽  
Peach Fruit ◽  
Chilling Temperatures ◽  
Cell Wall Enzymes ◽  
Polygalacturonase Activity

Tomato fruit (Solanum lycopersicon L.) can develop mealiness and enhanced softening when exposed to chilling temperatures during storage, but the involvement of cell wall-associated enzymes in chilling injury development is not well understood. To study this aspect of injury development, we have exposed breaker stage tomato cv. Trust fruit to a chilling temperature of 3 °C for 0, 7, 14, and 21 days followed by storage at 20 °C for 12 days. Ethylene production was not affected by storage except after 21 days, where production was greater at 20 °C. Exposure of fruit to chilling temperatures delayed the ripening-related color change (chroma and hue) and initially increased compression values, but percentage of extractable juice was not affected consistently. Increased polygalacturonase activity during ripening was reduced by about 50% after 7 days at 3 °C, and further inhibited with increasing storage periods. In contrast, the activities of pectin methylesterase and α-galactosidase were not significantly affected by the cold treatments. β-Galactosidase activity was greater in all chilled fruit compared with fruit ripened at harvest, whereas endo-β-1,4-glucanase activity was lower after 21 days at 3 °C. These results will be compared with equivalent changes in the activities of cell wall enzymes that are associated with wooliness development in chilling-injured peach fruit.

scholarly journals Effect of Intensity and Duration of Heat-shock Treatments on Wound-induced Phenolic Metabolism in Iceberg Lettuce

1997 ◽  
Vol 122 (6) ◽  
pp. 873-877 ◽  
Author(s):  
Julio G. Loaiza-Velarde ◽  
Francisco A. Tomás-Barberá ◽  
Mikal E. Saltveit
Keyword(s):  
Phenolic Compounds ◽  
Heat Shock ◽  
Chlorogenic Acid ◽  
Tartaric Acid ◽  
Phenylpropanoid Metabolism ◽  
Minimal Processing ◽  
Subsequent Increase ◽  
Phenolic Metabolism ◽  
Pal Activity ◽  
Iceberg Lettuce

Wounding during minimal processing of lettuce (Lactuca sativa, L.) induces alterations in phenolic metabolism that promote browning and the loss of quality. The activity of phenylalanine ammonia-lyase (PAL; the first committed enzyme in phenylpropanoid metabolism) and the concentration of phenolic compounds (e.g., chlorogenic acid, dicaffeoyl tartaric acid, and isochlorogenic acid) increase in excised iceberg lettuce midrib segments after wounding. The effect of short heat-shock treatments on browning and phenolic metabolism in excised midrib segments of iceberg lettuce was studied. As the heat-shock temperature increased from 20 to 70 °C, there was a decrease in the subsequent increase in PAL activity and the accumulation of phenolic compounds in excised midrib segments. Treatments of 45 °C for 120 s, 50 °C for 60 s, or 55 °C for 30 s significantly reduced the increase in PAL activity and subsequent browning seen in control tissue after wounding. Exposure to 45 °C for 480 s, 50 °C for 60 s, or 55 °C for 45 s prevented PAL activity from rising above initial levels. Phenolic compounds remained at initial levels for 3 days in excised midribs exposed to 50 °C for 90 s or to 55 °C for 60 s. However, 55 °C damaged the tissue, as indicated by a* and L* Hunter color values. The synthesis of chlorogenic acid, dicaffeoyl tartaric acid, and isochlorogenic acid was greatly reduced by these heat-shock treatments. These treatments also decreased polyphenol oxidase activity and, to a lesser extent, peroxidase activity.

scholarly journals 638 PB 366 EFFECTS OF PHENOLIC METABOLISM ON SUSCEPTIBILITY OF PEACH ROOTSTOCKS TO NEMATODES

HortScience ◽  
1994 ◽  
Vol 29 (5) ◽  
pp. 524b-524
Author(s):  
Yuan Yongbing ◽  
A. M. Simeone ◽  
P. Cappelini
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
Positive Relation ◽  
Phenol Content ◽  
Phenolic Metabolism ◽  
Common Features ◽  
Pal Activity ◽  
One Year ◽  
Peach Rootstocks ◽  
And Control

Peach rootstocks Rancho Resistant (RR) and GF 677 are resistant and susceptible to nematodes, respectively. One-year-old seedlings of RR, GF677 and their reciprocal grafts were inoculated with 10,000 larvae. Both inoculated and control plants were harvested at intervals for assay. Phenylalanine ammonia lyase (PAL) activity and soluble phenol content were enhanced in both RR and GF677 after inoculation, but RR always had a 2-fold higher peroxidase (PO) activity than GF677. When GF677 was grafted on RR, the resistance of RR was not altered. When RR was grafted onto GF677, the number of galls on the plant were 66% and 77% less than on GF677 2 weeks and 2 months after inoculation, respectively. However, no interaction was found in the reciprocal graft. The results showed that higher soluble phenol content and PAL activity induced by nematode attack were common features of RR and GF677, and a positive relation between PO activity and resistance to nematode existed in the two rootstocks.

scholarly journals EFFECTS OF INSECTICIDAL LOW-OXYGEN ATMOSPHERES ON POSTHARVEST PHYSIOLOGY AND QUALITY OF STONE FRUITS

HortScience ◽  
1990 ◽  
Vol 25 (9) ◽  
pp. 1140c-1140
Author(s):  
Dangyang Ke ◽  
Adel A. Kader
Keyword(s):  
Ethylene Production ◽  
Prunus Persica ◽  
Color Change ◽  
Physiological Responses ◽  
Chilling Injury ◽  
Limiting Factor ◽  
Stone Fruits ◽  
Prunus Domestica ◽  
Low Oxygen

Fruits of peach (Prunus persica L., cv. `Fairtime') and plum (Prunus domestica L., cv. `Angeleno') were kept in air and in 0.25% or 0.02% O2 at 0, 5, or 10°C for 3 to 40 days to study the effects of temperatures and insecticidal low O2 atmospheres on their physiological responses and quality attributes. Exposure to low O2 atmospheres reduced respiration and ethylene production rates of the stone fruits. The low O2 treatments retarded color change and flesh softening of plums and maintained acidity of peaches. Exposure to the low O2 atmospheres also delayed incidence and reduced severity of internal breakdown (chilling injury) and decay of the peaches at 5°C and, therefore, maintained both external and internal appearance qualities of the fruits longer than those kept in air. The most important limiting factor for fruit tolerance to insecticidal low O2 atmospheres was development of alcoholic off-flavor which was associated with accumulation of ethanol and acetaldehyde in the fruits. The peaches and plums could tolerate exposures to the low O2 atmospheres for 9 to 40 days, depending on the temperature and O2 level used. These results suggest that stone fruits are quite tolerant to insecticidal low O2 atmospheres.

scholarly journals Wound-induced Phenolic Accumulation and Browning in Lettuce (Lactucasativa L.) Leaf Tissue is Reduced by Exposure to n-alcohols

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1131B-1131
Author(s):  
Mikal Saltveit ◽  
Youngjun Choi ◽  
Francisco Tomás-Barberán
Keyword(s):  
Phenylalanine Ammonia Lyase ◽  
De Novo ◽  
Physiological Responses ◽  
Leaf Tissue ◽  
De Novo Synthesis ◽  
Phenolic Metabolism ◽  
Pal Activity ◽  
Wound Signal ◽  
Fresh Cut ◽  
Tissue Browning

A wound signal originates at the site of injury in lettuce [Lactucasativa (L.)] leaf tissue and propagates into adjacent tissue where it induces a number of physiological responses that include increased phenolic metabolism with the de novo synthesis of phenylalanine ammonia lyase (PAL, EC 4.3.1.5), the synthesis and accumulation of soluble phenolic compounds (e.g., chlorogenic acid), and subsequent tissue browning. Exposing excised mid-rib leaf tissue to vapors (20 μmol·g-1 FW) or aqueous solutions (100 mm) of n-alcohols inhibited this wound-induced tissue browning by 40% and 60%, respectively. Effectiveness of the alcohol increased linearly from ethanol to the seven-carbon heptanol, and then was lost for the longer n-alcohols 1-octanol and 1-nonanol. The 2- and 3-isomers of the effective alcohols did not significantly reduce wound-induced phenolic accumulation at optimal 1-alcohol concentrations, but significant reductions did occur at much higher concentrations (100 μmol·g-1 FW) of the 2-, and 3-isomers. The active n-alcohols were maximally effective when applied during the first 2 h after excision, and were ineffective if applied 12 h after excision. Phospholipase D (PLD) and its product phosphatidic acid (PA) are thought to initiate the oxylipin pathway that culminates in the production of jasmonic acid, and PLD is specifically inhibited by 1-butanol, but not by 2- or 3-butanol. These results suggest that PLD, PA, and the oxylipin pathway may be involved in producing the wound signal responsible for increased wound-induced PAL activity, phenolic accumulation, and browning in fresh-cut lettuce leaf tissue.

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