Ultrastructure of Tomato Fruit Ripening and the Role of Polygalacturonase Isoenzymes in Cell Wall Degradation

Radioisotope 45Ca was used to examine changes in levels of bound and soluble calcium during tomato fruit ripening, and the distribution of calcium in different regions of Rutgers and Rin (non-ripening) tomato tissue. Levels of cell wallmiddle lamella bound 45Ca decreased readily in pericarp tissue during ripening of Rutgers tomatoes with only as mall decrease being observed in RIN fruit. No significant increase in soluble 45Ca was observed for either genotype during ripening. Decreasing levels of bound and soluble 45Ca were observed from calyx to blossom end of pericarp tissue in Rutgers and RIN fruits. Low levels of bound 45Ca were found in the inner locular walls at an early stage of tomato ripening. The implication of low levels of cell wall bound calcium in relation to catabolic changes associated with ripening are discussed.

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Regulation of Postharvest Tomato Fruit Ripening by Endogenous Salicylic Acid

Frontiers in Plant Science ◽

10.3389/fpls.2021.663943 ◽

2021 ◽

Vol 12 ◽

Author(s):

Chunoti Changwal ◽

Tushita Shukla ◽

Zakir Hussain ◽

Neera Singh ◽

Abhijit Kar ◽

...

Keyword(s):

Lipid Peroxidation ◽

Salicylic Acid ◽

Carboxylic Acid ◽

Fruit Ripening ◽

Tomato Fruit ◽

Stability Index ◽

Acid Oxidase ◽

Tomato Fruit Ripening ◽

Lycopene Content

Exogenous application of salicylic acid (SA) has been known for delaying ripening in many fruit and vegetables. But the function of endogenous SA in relation to postharvest fruit performance is still unexplored. To understand the role of endogenous SA in postharvest fruit ripening of tomato, 33 tomato lines were examined for their endogenous SA content, membrane stability index (MSI), and shelf life (SL) at turning and red stages of tomato fruit ripening. Six tomato lines having contrasting shelf lives from these categories were subjected further for ethylene (ET) evolution, 1-aminocyclopropane-1-carboxylic acid synthase (ACS), 1-aminocyclopropane-1-carboxylic acid oxidase (ACO), polygalacturonase (PG), pectin methyl esterase (PME), antioxidant assays and lipid peroxidation. It was found that high endogenous SA has a direct association with low ET evolution, which leads to the high SL of fruit. High lycopene content was also found to be correlated with high SA. Total antioxidants, PG, and PME decreased and lipid peroxidation increased from turning to red stage of tomato fruit development. Furthermore, these lines were subjected to expression analysis for SA biosynthesis enzymes viz. Solanum lycopersicum Isochorismate Synthase (SlICS) and SlPAL. Real-time PCR data revealed that high SL lines have high SlPAL4 expression and low SL lines have high SlPAL6 expression. Based on the results obtained in this study, it was concluded that endogenous SA regulates ET evolution and SL with the aid of the antioxidative defense system, and SlPAL4 and SlPAL6 genes play significant but opposite roles during fruit ripening.

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Carotenoid biosynthesis and accumulation during tomato fruit ripening: role of plastoglobules and other suborganellar structures

New Biotechnology ◽

10.1016/j.nbt.2012.08.505 ◽

2012 ◽

Vol 29 ◽

pp. S181

Author(s):

Karel de Pourcq ◽

Albert Boronat

Keyword(s):

Fruit Ripening ◽

Tomato Fruit ◽

Carotenoid Biosynthesis ◽

Tomato Fruit Ripening

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Role of pectin methylesterase in tomato fruit ripening and quality attributes of processed tomato juice

Progress in Biotechnology - Pectins and Pectinases, Proceedings of an International Symposium ◽

10.1016/s0921-0423(96)80267-x ◽

1996 ◽

pp. 355-368 ◽

Cited By ~ 3

Author(s):

A.K. Handa ◽

D.M. Tieman ◽

K.K. Mishra ◽

B.R. Thakur ◽

R.K. Singh

Keyword(s):

Fruit Ripening ◽

Tomato Fruit ◽

Pectin Methylesterase ◽

Quality Attributes ◽

Tomato Juice ◽

Tomato Fruit Ripening

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Rosmarinic Acid Delays Tomato Fruit Ripening by Regulating Ripening-Associated Traits

Antioxidants ◽

10.3390/antiox10111821 ◽

2021 ◽

Vol 10 (11) ◽

pp. 1821

Author(s):

Changan Zhu ◽

Shaofang Wu ◽

Ting Sun ◽

Zhiwen Zhou ◽

Zhangjian Hu ◽

...

Keyword(s):

Shelf Life ◽

Fruit Ripening ◽

Rosmarinic Acid ◽

Color Change ◽

Tomato Fruit ◽

Tomato Fruits ◽

Tomato Fruit Ripening ◽

Sensory Evolution ◽

Reduced Forms

Fruits are excellent sources of essential vitamins and health-boosting minerals. Recently, regulation of fruit ripening by both internal and external cues for the improvement of fruit quality and shelf life has received considerable attention. Rosmarinic acid (RA) is a kind of natural plant-derived polyphenol, widely used in the drug therapy and food industry due to its distinct physiological functions. However, the role of RA in plant growth and development, especially at the postharvest period of fruits, remains largely unknown. Here, we demonstrated that postharvest RA treatment delayed the ripening in tomato fruits. Exogenous application of RA decreased ripening-associated ethylene production and inhibited the fruit color change from green to red based on the decline in lycopene accumulation. We also found that the degradation of sucrose and malic acid during ripening was significantly suppressed in RA-treated tomato fruits. The results of metabolite profiling showed that RA application promoted the accumulation of multiple amino acids in tomato fruits, such as aspartic acid, serine, tyrosine, and proline. Meanwhile, RA application also strengthened the antioxidant system by increasing both the activity of antioxidant enzymes and the contents of reduced forms of antioxidants. These findings not only unveiled a novel function of RA in fruit ripening, but also indicated an attractive strategy to manage and improve shelf life, flavor, and sensory evolution of tomato fruits.

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A tomato LATERAL ORGAN BOUNDARIES transcription factor, SlLOB1, predominantly regulates cell wall and softening components of ripening

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2102486118 ◽

2021 ◽

Vol 118 (33) ◽

pp. e2102486118

Author(s):

Yanna Shi ◽

Julia Vrebalov ◽

Hui Zheng ◽

Yimin Xu ◽

Xueren Yin ◽

...

Keyword(s):

Cell Wall ◽

Tomato Fruit ◽

35S Promoter ◽

Protein Levels ◽

Physiological Processes ◽

Tomato Fruit Ripening ◽

Lateral Organ ◽

Textural Changes ◽

Late Maturation

Fruit softening is a key component of the irreversible ripening program, contributing to the palatability necessary for frugivore-mediated seed dispersal. The underlying textural changes are complex and result from cell wall remodeling and changes in both cell adhesion and turgor. While a number of transcription factors (TFs) that regulate ripening have been identified, these affect most canonical ripening-related physiological processes. Here, we show that a tomato fruit ripening–specific LATERAL ORGAN BOUNDRIES (LOB) TF, SlLOB1, up-regulates a suite of cell wall–associated genes during late maturation and ripening of locule and pericarp tissues. SlLOB1 repression in transgenic fruit impedes softening, while overexpression throughout the plant under the direction of the 35s promoter confers precocious induction of cell wall gene expression and premature softening. Transcript and protein levels of the wall-loosening protein EXPANSIN1 (EXP1) are strongly suppressed in SlLOB1 RNA interference lines, while EXP1 is induced in SlLOB1-overexpressing transgenic leaves and fruit. In contrast to the role of ethylene and previously characterized ripening TFs, which are comprehensive facilitators of ripening phenomena including softening, SlLOB1 participates in a regulatory subcircuit predominant to cell wall dynamics and softening.

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Cell Wall Degradation in Irradiated Tomato Fruit

HortScience ◽

10.21273/hortsci.30.4.815b ◽

1995 ◽

Vol 30 (4) ◽

pp. 815B-815

Author(s):

N. El-Assi ◽

D.J. Huber ◽

J.K. Brecht

Keyword(s):

Cell Wall ◽

Tomato Fruit ◽

Selective Extraction ◽

Specific Cell ◽

Neutral Sugar ◽

Cell Wall Degradation ◽

X Ray ◽

Green Fruit ◽

Cell Wall Polymers

The irradiation of harvested fruit is typically accompanied by excessive tissue softening, a process that is not well understood. In this study, we examined the role of specific cell wall polymers and the extent of general cell wall degradation and softening in irradiated tomato fruit. `Sunny' tomato fruit at mature-green and pink stages were subjected to X-ray radiation at 0, 83, and 156 Krad. Immediate softening was noted for both maturation classes, although some postirradiation recovery was evident in green fruit. Pectic polymers of both mature-green and pink fruit exhibited depolymerization and altered neutral sugar profiles in response to irradiation. Pectins, either as components of total ethanol-insoluble solids (EIS), purified by selective extraction, or of commercial origin were similarly affected by irradiation. Cellulose preparations were unaffected by irradiation. The data demonstrate that the effect of irradiation on the cell wall exhibits specificity, can occur nonenzymatically, and does not require initiating adducts of cytosolic origin.

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