scholarly journals Genome wide identification and functional characterization of strawberry pectin methylesterases related to fruit softening

2020 ◽  
Vol 20 (1) ◽  
Author(s):  
Cheng Xue ◽  
Si-Cong Guan ◽  
Jian-Qing Chen ◽  
Chen-Jin Wen ◽  
Jian-Fa Cai ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fruit Ripening ◽  
Genetic Manipulation ◽  
Functional Characterization ◽  
Hydrolytic Enzyme ◽  
Wall Structure ◽  
Fruit Softening ◽  
Fruit Firmness ◽  
Strawberry Fruit ◽  
Cell Wall Modification

Abstract Background Pectin methylesterase (PME) is a hydrolytic enzyme that catalyzes the demethylesterification of homogalacturonans and controls pectin reconstruction, being essential in regulation of cell wall modification. During fruit ripening stage, PME-mediated cell wall remodeling is an important process to determine fruit firmness and softening. Strawberry fruit is a soft fruit with a short postharvest life, due to a rapid loss of firm texture. Hence, preharvest improvement of strawberry fruit rigidity is a prerequisite for extension of fruit refreshing time. Although PME has been well characterized in model plants, knowledge regarding the functionality and evolutionary property of PME gene family in strawberry remain limited. Results A total of 54 PME genes (FvPMEs) were identified in woodland strawberry (Fragaria vesca ‘Hawaii 4’). Phylogeny and gene structure analysis divided these FvPME genes into four groups (Group 1–4). Duplicate events analysis suggested that tandem and dispersed duplications effectively contributed to the expansion of the PME family in strawberry. Through transcriptome analysis, we identified FvPME38 and FvPME39 as the most abundant-expressed PMEs at fruit ripening stages, and they were positively regulated by abscisic acid. Genetic manipulation of FvPME38 and FvPME39 by overexpression and RNAi-silencing significantly influences the fruit firmness, pectin content and cell wall structure, indicating a requirement of PME for strawberry fruit softening. Conclusion Our study globally analyzed strawberry pectin methylesterases by the approaches of phylogenetics, evolutionary prediction and genetic analysis. We verified the essential role of FvPME38 and FvPME39 in regulation of strawberry fruit softening process, which provided a guide for improving strawberry fruit firmness by modifying PME level.

scholarly journals FvMYB79 Positively Regulates Strawberry Fruit Softening via Transcriptional Activation of FvPME38

2021 ◽  
Vol 23 (1) ◽  
pp. 101
Author(s):  
Jianfa Cai ◽  
Xuelian Mo ◽  
Chenjin Wen ◽  
Zhen Gao ◽  
Xu Chen ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Transcriptional Activation ◽  
Developmental Stages ◽  
Pectin Methylesterase ◽  
Myb Transcription Factor ◽  
Transcriptional Level ◽  
Fruit Softening ◽  
Fruit Firmness ◽  
Strawberry Fruit ◽  
Softening Process

Strawberry is a soft fruit with short postharvest life, due to a rapid loss of firmness. Pectin methylesterase (PME)-mediated cell wall remodeling is important to determine fruit firmness and softening. Previously, we have verified the essential role of FvPME38 in regulation of PME-mediated strawberry fruit softening. However, the regulatory network involved in PME-mediated fruit softening is still largely unknown. Here, we identified an R2R3-type MYB transcription factor FvMYB79, which activates the expression level of FvPME38, thereby accelerating fruit softening. During fruit development, FvMYB79 co-expressed with FvPME38, and this co-expression pattern was opposite to the change of fruit firmness in the fruit of ‘Ruegen’ which significantly decreased during fruit developmental stages and suddenly became very low after the color turning stage. Via transient transformation, FvMYB79 could significantly increase the transcriptional level of FvPME38, leading to a decrease of firmness and acceleration of fruit ripening. In addition, silencing of FvMYB79 showed an insensitivity to ABA-induced fruit ripening, suggesting a possible involvement of FvMYB79 in the ABA-dependent fruit softening process. Our findings suggest FvMYB79 acts as a novel regulator during strawberry ripening via transcriptional activation of FvPME38, which provides a novel mechanism for improvement of strawberry fruit firmness.

scholarly journals Genome-Wide Identification and Expression Analysis of Polygalacturonase Gene Family in Kiwifruit (Actinidia chinensis) during Fruit Softening

Plants ◽  
2020 ◽  
Vol 9 (3) ◽  
pp. 327
Author(s):  
Wenjun Huang ◽  
Meiyan Chen ◽  
Tingting Zhao ◽  
Fei Han ◽  
Qi Zhang ◽  
...  
Keyword(s):  
Gene Family ◽  
Genetic Manipulation ◽  
Functional Characterization ◽  
Hydrolytic Enzyme ◽  
Pectin Methylesterase ◽  
Fruit Softening ◽  
Actinidia Chinensis ◽  
Separation Processes ◽  
Pectin Content ◽  
Pectin Lyases

Polygalacturonase (PG) is an essential hydrolytic enzyme responsible for pectin degradation and thus plays an important role in fruit softening and other cell separation processes. PG protein is encoded by a multigene family, however, the members of PG gene family in kiwifruit (Actinidia chinensis) have not been extensively identified. In this study, a total of 51 AcPG genes in kiwifruit genome were identified. They are phylogenetically clustered into seven clades, and of them AcPG4 and AcPG18 with other known PG genes involved in fruit softening from peach, pear, papaya and melon form a small cluster together. The members of kiwifruit PG gene family consist of three to nine exons and two to eight introns, and their exon/intron structures are generally conserved in all clades except the clade D and E. During fruit softening of kiwifruit ‘Donghong’ under ambient temperature, cell wall modifying enzymes, including PG, PL (pectate and pectin lyases), and PE (pectinesterase, also known as pectin methylesterase, PME) showed a different activity profile, and of them, PG and PE activities largely correlated with the change of pectin content and firmness. Moreover, only 11 AcPG genes were highly or moderately expressed in softening fruit, and of which three AcPG genes (AcPG4, AcPG18, and AcPG8, especially the former two) has been found to strongly correlate with the profile of PG activity and pectin content, as well as fruit firmness, suggesting that they maybe play an important role in fruit softening. Thus, our findings not only benefit the functional characterization of kiwifruit PG genes, but also provide a subset of potential PG candidate genes for further genetic manipulation.

scholarly journals Modifications in the methods to extract pectin from cv. “Pedro Sato” guavas during ripening

2018 ◽  
Vol 21 (0) ◽  
Author(s):  
Samira Haddad Spiller ◽  
Tamara Rezende Marques ◽  
Anderson Assaid Simão ◽  
Mariana Aparecida Braga ◽  
Lucimara Nazaré Silva Botelho ◽  
...  
Keyword(s):  
Cell Wall ◽  
Shelf Life ◽  
Room Temperature ◽  
Hydrolytic Enzymes ◽  
Cell Wall Structure ◽  
Wall Structure ◽  
Fruit Firmness ◽  
Edta Extraction

Abstract Guava is a highly perishable fruit due to its intense metabolism during ripening, with a shelf life of up to five days at room temperature. The loss of firmness during ripening is caused by the activity of hydrolytic enzymes that promote dissolution of the pectin constituents of the cell wall. Although guava is considered to be rich in pectin, the amounts reported in the literature do not exceed 2.4%, a content indicating it is not responsible for the firmness of guava. The aim of this study was to extract pectin from the guava pulp during 7 days of ripening by two methods (ethanol and EDTA extraction) and suggest modifications in the methods by adding to the extraction residue, cellulase and pectinase to degrade the cell wall structure of the fruit and obtain larger amounts of pectin, which would imply the participation of pectin in the maintenance of fruit firmness. It was possible to infer there were no differences in the pectin levels extracted by the two methods, due to sugar contamination. As from the new stage in the execution by the two methods, the extraction was more efficient: 9.10% of pectin with EDTA and 7.63% with ethanol. The pectin contents found were higher than those mentioned in the literature, better explaining their responsibility in fruit firmness.

EFFECT OF SILENCING OF CELL WALL DEGRADING ENZYMES ON STRAWBERRY FRUIT SOFTENING

2009 ◽  
pp. 931-934 ◽  
Author(s):  
M.A. Quesada ◽  
S. Posé ◽  
N. Santiago-Doménech ◽  
R. Sesmero ◽  
M.C. Molina ◽  
...  
Keyword(s):  
Cell Wall ◽  
Fruit Softening ◽  
Strawberry Fruit ◽  
Cell Wall Degrading Enzymes ◽  
Degrading Enzymes

scholarly journals (472) Yeast Expressed Tomato β-Galactosidases 1, 4, and 5 Have Activity against Synthetic and Plant-derived Cell Wall Substrates

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1092B-1092 ◽  
Author(s):  
Megumi Ishimaru ◽  
David L. Smith ◽  
Kenneth C. Gross
Keyword(s):  
Cell Wall ◽  
Tomato Fruit ◽  
Wall Material ◽  
Wall Structure ◽  
Fruit Softening ◽  
Pectic Polysaccharides ◽  
Wide Range ◽  
Fruit Pericarp ◽  
Galactosyl Residues

Fruit softening occurs by several mechanisms, including modifications of cell wall structure by wall degrading enzymes. The most prominent change in tomato fruit pericarp wall composition is the loss of galactosyl residues throughout development and especially during ripening. In order to understand the role of galactosyl turnover in fruit softening, we successfully produced three recombinant tomato β-galactosidase/exo-galactanase (TBG) fusion proteins in yeast. TBG1, 4 and 5 enzyme properties and substrate specificities were assessed. Optimum pH of TBG1, 4 and 5 was 5.0, 4.0, and 4.5 and optimum temperature was 40∼50, 40, and 40 °C, respectively. The K ms for TBG1, 4 and 5 were 7.99, 0.09, and 2.42 mm, respectively, using p-nitrophenyl-β-D-galactopyranoside as substrate. Using synthetic and plant-derived substrates, TBG1 and 5 released galactosyl residues from 1 → 4 linkages. TBG4 released galactosyl residues from a wide range of plant-derived oligosaccharides and polysaccharides. Using tomato fruit cell wall material, TBG1, TBG4 and TBG5 released galactosyl residues from a variety of fruit stages and cell wall fractions. TBG4 released the most galactosyl residues from the ASP fraction and especially the ASP fraction from fruit at the turning stage. Interestingly, even though walls from Turning fruit stage contain less total galactosyl residues than at the Mature Green stage, TBG4 released 3–4 fold more galactose from the CSP and ASP fractions from Turning fruit. These results suggest that changes in structure of wall pectic polysaccharides leading up to the Turning stage may cause the wall to become more susceptible to hydrolysis by the TBG4 product.

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