Role of Ethylene in the Biosynthesis of Fatty Acid-Derived Volatiles in Tomato Fruits

2011 ◽  
Vol 343-344 ◽  
pp. 937-950
Author(s):  
Yuan Hong Xie ◽  
Hong Yan Gao ◽  
Yun Bo Luo ◽  
Hong Xing Zhang ◽  
Xiang Ning Chen ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Linolenic Acid ◽  
Tomato Fruit ◽  
Ethylene Biosynthesis ◽  
Hydroperoxide Lyase ◽  
Wild Type ◽  
Tomato Fruits ◽  
Aroma Volatiles ◽  
Exogenous Ethylene

Regulation of ethylene biosynthesis or action has an important effect on volatiles production in tomato (Lycopersicon esculentum) fruits. To understand the role of ethylene in the biosynthesis of fatty acid-derived aroma volatiles in tomato, we used Lichun tomato from a transgenic line with strictly suppression of ethylene biosynthesis (antisenseLeACS2tomato) and its wild type background line. This study was focused on the levels of the precursor substrates, activities and transcriptional levels of aroma volatile-related enzymes, including lipoxygenase (LOX), hydroperoxide lyase (HPL) and alcohol dehydrogenase (ADH). We also investigated the different abilities of converting the precursor substrates to aroma volatiles in ethylene suppressed transgenic and wild-type (WT) tomato fruits. Our results showed that the contents of endogenous linoleic and linolenic acid in tomato fruits were ethylene depended. Suppression of ethylene biosynthesis increased the content of endogenous linolenic acid inLichuntomato fruit and then declined the ratio of linoleic /linolenic acid. Exogenous ethylene changed the value of linoleic acid /linolenic acid in antisenseLeACS2(ACS) tomato fruit to the similar level of WT. During the ripening of wild type Lichun tomato fruit, LOX activity was ethylene and development dependent. Suppression of ethylene biosynthesis did not inhibit the transcriptional expression ofLoxCgene. And the HPL and ADH activities were partial ethylene-dependent during the ripening of wild typeLichuntomato fruit. Moreover, suppression of ethylene biosynthesis also affected the bioconversion of unsaturated-fatty acid precursors to C6 aldehydes and C6 alcohols. All these results indicated that ethylene had complicated effects on the biosynthesis of fatty acid-derived armoa volatiles by affecting the precursor’s content, enzyme activities, enzyme expression and the substrate utilization.

scholarly journals Role Of Selected Fimbrial Adheins In Pathogenesis Of Acid-Induced Eneterohemorrhagic Escherichia Coli 0157:H7

2021 ◽  
Author(s):  
Shahnaz Haque
Keyword(s):  
Fatty Acid ◽  
Type Strain ◽  
Wild Type Strain ◽  
Short Chain Fatty Acid ◽  
Acid Stress ◽  
Chain Fatty Acid ◽  
Short Chain ◽  
Wild Type ◽  
Food Borne

Enterohemorrhagic Escherichia coli (EHEC) 0157:H7 is a food-borne pathogen that causes hemolytic uremic syndrome and hemorrhagic colitis. The mechanisms underlying the adhesion of EHEC 0157:H7 to intestinal epithelial cells are not well understood. Like other food-borne pathogens, ECEC 0157:H7 must survive the acid stress of the gastric juice in the stomach and short chain fatty acid in the intestine in order to colonize the large intestine. We have found that acid stress and short chain fatty acid stress significantly enhance host-adhesion of EHEC 0157:H7 and also upregulates expression of EHEC fimbrial genes, lpfA1, lpfA2 and yagZ, as demonstrated by our DNA microarray. We now report that disruption of the yagZ (also known as the E. coli common pilus A) gene results in loss of the acid-induced and short chain fatty acid-induced adhesion increase seen for the wild type strain. When the yagZ mutant is complemented with yagZ, the sress-induced and short chain fatty acid-induced adhesion increase seen for the wild type strain. When the yagZ mutant is complemented with yagZ, the stress-induced adhesion pehnotype is restored, confirming the role of yagZ in the acid as well as short chain fatty acid induced adhesion to HEp-2 cells. On the other hand, neither disruption in the long polar fimbria genes lpfA1 or lpfA2 in the wild type showed any effect in adherence to HEp-2 cells; rather displaying a hyperadherant phenotype to HEp-2 cells after acid-induced or short chain fatty acid-induced stress. The results also indicate that acid or short chain fatty acid stress, which is a part of the host's natural defense mechanism against pathogens, may regulate virulence factors resulting in enhanced bacteria-host attachment during colonization in the human or bovine host.

scholarly journals Free Fatty Acid Receptor 4 (GPR120) Stimulates Bone Formation and Suppresses Bone Resorption in the Presence of Elevated n-3 Fatty Acid Levels

Endocrinology ◽  
2016 ◽  
Vol 157 (7) ◽  
pp. 2621-2635 ◽  
Author(s):  
Seong Hee Ahn ◽  
Sook-Young Park ◽  
Ji-Eun Baek ◽  
Su-Youn Lee ◽  
Wook-Young Baek ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Free Fatty Acid ◽  
Bone Resorption ◽  
Bone Loss ◽  
Bone Formation ◽  
High Fat Diet ◽  
Wild Type ◽  
High Fat ◽  
Free Fatty Acid Receptor

Free fatty acid receptor 4 (FFA4) has been reported to be a receptor for n-3 fatty acids (FAs). Although n-3 FAs are beneficial for bone health, a role of FFA4 in bone metabolism has been rarely investigated. We noted that FFA4 was more abundantly expressed in both mature osteoclasts and osteoblasts than their respective precursors and that it was activated by docosahexaenoic acid. FFA4 knockout (Ffar4−/−) and wild-type mice exhibited similar bone masses when fed a normal diet. Because fat-1 transgenic (fat-1Tg+) mice endogenously converting n-6 to n-3 FAs contain high n-3 FA levels, we crossed Ffar4−/− and fat-1Tg+ mice over two generations to generate four genotypes of mice littermates: Ffar4+/+;fat-1Tg−, Ffar4+/+;fat-1Tg+, Ffar4−/−;fat-1Tg−, and Ffar4−/−;fat-1Tg+. Female and male littermates were included in ovariectomy- and high-fat diet-induced bone loss models, respectively. Female fat-1Tg+ mice decreased bone loss after ovariectomy both by promoting osteoblastic bone formation and inhibiting osteoclastic bone resorption than their wild-type littermates, only when they had the Ffar4+/+ background, but not the Ffar4−/− background. In a high-fat diet-fed model, male fat-1Tg+ mice had higher bone mass resulting from stimulated bone formation and reduced bone resorption than their wild-type littermates, only when they had the Ffar4+/+ background, but not the Ffar4−/− background. In vitro studies supported the role of FFA4 as n-3 FA receptor in bone metabolism. In conclusion, FFA4 is a dual-acting factor that increases osteoblastic bone formation and decreases osteoclastic bone resorption, suggesting that it may be an ideal target for modulating metabolic bone diseases.

scholarly journals Re-evaluation of the nor mutation and the role of the NAC-NOR transcription factor in tomato fruit ripening

2020 ◽  
Vol 71 (12) ◽  
pp. 3560-3574 ◽  
Author(s):  
Ying Gao ◽  
Wei Wei ◽  
Zhongqi Fan ◽  
Xiaodan Zhao ◽  
Yiping Zhang ◽  
...  
Keyword(s):  
Fruit Ripening ◽  
Tomato Fruit ◽  
Pectate Lyase ◽  
Ethylene Biosynthesis ◽  
Fruit Softening ◽  
Wild Type ◽  
Gain Of Function ◽  
Carotenoid Accumulation ◽  
Acid Protein ◽  
Tomato Fruit Ripening

Abstract The tomato non-ripening (nor) mutant generates a truncated 186-amino-acid protein (NOR186) and has been demonstrated previously to be a gain-of-function mutant. Here, we provide more evidence to support this view and answer the open question of whether the NAC-NOR gene is important in fruit ripening. Overexpression of NAC-NOR in the nor mutant did not restore the full ripening phenotype. Further analysis showed that the truncated NOR186 protein is located in the nucleus and binds to but does not activate the promoters of 1-aminocyclopropane-1-carboxylic acid synthase2 (SlACS2), geranylgeranyl diphosphate synthase2 (SlGgpps2), and pectate lyase (SlPL), which are involved in ethylene biosynthesis, carotenoid accumulation, and fruit softening, respectively. The activation of the promoters by the wild-type NOR protein can be inhibited by the mutant NOR186 protein. On the other hand, ethylene synthesis, carotenoid accumulation, and fruit softening were significantly inhibited in CR-NOR (CRISPR/Cas9-edited NAC-NOR) fruit compared with the wild-type, but much less severely affected than in the nor mutant, while they were accelerated in OE-NOR (overexpressed NAC-NOR) fruit. These data further indicated that nor is a gain-of-function mutation and NAC-NOR plays a significant role in ripening of wild-type fruit.

Expression of Lipoxygenase and Hydroperoxide Lyase Activities in Tomato Fruits

1992 ◽  
Vol 47 (5-6) ◽  
pp. 369-374 ◽  
Author(s):  
Akikazu Hatanaka ◽  
Tadahiko Kajiwara ◽  
Kenji Matsui ◽  
Akira Kitamura
Keyword(s):  
Linoleic Acid ◽  
Uv Irradiation ◽  
Tissue Specificity ◽  
Tomato Fruit ◽  
Hydroperoxide Lyase ◽  
Tomato Fruits ◽  
Low Level ◽  
Ripe Tomato

The distribution (or locarization) of lipoxygenase (LOX) and hydroperoxide lyase (HPO lyase) activities in ripening and ripe tomato fruits was investigated. The highest LOX activity existed between skin and outer flesh of tomato fruits. HPO lyase showed no tissue specificity. LOX specifically formed linoleic acid 9-E, Z-hydroperoxide (9-E, Z-HPO) from linoleic acid (LA), whereas HPO lyase specifically cleaved 13-Z, E-HPO. Although a low level (0.36 ± 0.069 nmol/g fr. wt.) of hexanal was detected in the intact tomato fruit, HPOs were not detected. When a tomato fruit was injured by cutting it into 8 fragments and incubated at 25 °C, hexanal increased to 1.642 nmol/g fr.wt. by 30 min. By homogenizing at pH 6.3, hexanal increased to 21.1 nmol/g fr.wt. during a 30 min incubation. UV irradiation of tomato fruits also increased the formation of hexanal. From these results, LOX and HPO lyase are considered to exist as latent forms and to begin the expression of the activity upon injury.

scholarly journals A Positive Role for Rhizobitoxine in Rhizobium-legume Symbiosis

1999 ◽  
Vol 12 (12) ◽  
pp. 1082-1089 ◽  
Author(s):  
Samuel Duodu ◽  
T. V. Bhuvaneswari ◽  
Thomas J. W. Stokkermans ◽  
N. Kent Peters
Keyword(s):  
Ethylene Biosynthesis ◽  
Nodule Development ◽  
Ethylene Inhibitors ◽  
Wild Type ◽  
Positive Role ◽  
Rate Limiting Step ◽  
Mutant Strains ◽  
Legume Symbiosis ◽  
Exogenous Ethylene ◽  
Rate Limiting

Although Bradyrhizobium elkanii is a mutualistic symbiont of legumes, it synthesizes a phytotoxin, rhizobitoxine, that causes chlorosis on a variety of legume hosts, giving a pathogenic character to these interactions. No positive role for rhizobitoxine has been previously demonstrated. Interestingly, rhizobitoxine inhibits the rate-limiting step for ethylene biosynthesis, a plant hormone known to inhibit or down-regulate nodule development. We hypothesized that rhizobitoxine plays a positive role in nodule development through its inhibition of ethylene biosynthesis. To test this hypothesis, host plants of B. elkanii were screened for a differential nodulation response to the wild-type and rhizobitoxine mutant strains. In Vigna radiata (mungbean), the rhizobitoxine mutant strains induced many aborted nodules arrested at all stages of pre-emergent and post-emergent development and formed significantly fewer mature nodules than the wild type. Experiments revealed that nodulation of mungbean plants is sensitive to exogenous ethylene, and that the ethylene inhibitors aminoethoxyvinylglycine and Co2+ were able to partially restore a wild-type nodulation pattern to the rhizobitoxine mutants. This is the first demonstration of a nodulation phenotype of the rhizobitoxine mutants and suggests that rhizobitoxine plays a positive and necessary role in Rhizobium-legume symbiosis through its inhibition of ethylene biosynthesis.

scholarly journals Active role of fatty acid amino acid conjugates in nitrogen metabolism in Spodoptera litura larvae

2008 ◽  
Vol 105 (46) ◽  
pp. 18058-18063 ◽  
Author(s):  
Naoko Yoshinaga ◽  
Takako Aboshi ◽  
Hiroaki Abe ◽  
Ritsuo Nishida ◽  
Hans T. Alborn ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Amino Acid ◽  
Glutamic Acid ◽  
Linolenic Acid ◽  
Nitrogen Metabolism ◽  
Spodoptera Litura ◽  
Nitrogen Assimilation ◽  
Assimilation Efficiency ◽  
Active Role

Since the first fatty acid amino acid conjugate (FAC) was isolated from regurgitant of Spodoptera exigua larvae in 1997 [volicitin: N-(17-hydroxylinolenoyl)-l-glutamine], their role as elicitors of induced responses in plants has been well documented. However, studies of the biosyntheses and the physiological role of FACs in the insect have been minimal. By using 14C-labeled glutamine, glutamic acid, and linolenic acid in feeding studies of Spodoptera litura larvae, combined with tissue analyses, we found glutamine in the midgut cells to be a major source for biosynthesis of FACs. Furthermore, 20% of the glutamine moiety of FACs was derived from glutamic acid and ammonia through enzymatic reaction of glutamine synthetase (GS). To determine whether FACs improve GS productivity, we studied nitrogen assimilation efficiency of S. litura larvae fed on artificial diets containing 15NH4Cl and glutamic acid. When the diet was enriched with linolenic acid, the nitrogen assimilation efficiency improved from 40% to >60%. In the lumen, the biosynthesized FACs are hydrolyzed to fatty acids and glutamine, which are reabsorbed into tissues and hemolymph. These results strongly suggested that FACs play an active role in nitrogen assimilation in Lepidoptera larva and that glutamine containing FACs in the gut lumen may function as a form of storage of glutamine, a key compound of nitrogen metabolism.

scholarly journals Reduced SCD1 activity alters markers of fatty acid reesterification, glyceroneogenesis, and lipolysis in murine white adipose tissue and 3T3-L1 adipocytes

2017 ◽  
Vol 313 (3) ◽  
pp. C295-C304 ◽  
Author(s):  
Steven M. Dragos ◽  
Karl F. Bergeron ◽  
Frédérik Desmarais ◽  
Katherine Suitor ◽  
David C. Wright ◽  
...  
Keyword(s):  
Gene Expression ◽  
Adipose Tissue ◽  
Fatty Acid ◽  
White Adipose Tissue ◽  
Phosphoenolpyruvate Carboxykinase ◽  
Critical Role ◽  
Wild Type ◽  
Important Regulator ◽  
Specific Regulation

White adipose tissue (WAT) has a critical role in lipid handling. Previous work demonstrated that SCD1 is an important regulator of WAT fatty acid (FA) composition; however, its influence on the various interconnected pathways influencing WAT lipid handling remains unclear. Our objective was to investigate the role of SCD1 on WAT lipid handling using Scd1 knockout (KO) mice and SCD1-inhibited 3T3-L1 adipocytes by measuring gene, protein, and metabolite markers related to FA reesterification, glyceroneogenesis, and lipolysis. Triacylglycerol (TAG) content was higher in inguinal WAT (iWAT) from KO mice compared with wild-type, but significantly lower in epididymal WAT (eWAT). The SCD1 desaturation index was decreased in both WAT depots in KO mice. FA reesterification, as measured with a NEFA:glycerol ratio, was reduced in both WAT depots in KO mice, as well as SCD1-inhibited 3T3-L1 adipocytes. Pck1, Atgl, and Hsl gene expression was reduced in both WAT depots of KO mice, while Pck2 and Pdk4 gene expression showed depot-specific regulation. Pck1, Atgl, and Hsl gene expression was reduced, and phosphoenolpyruvate carboxykinase protein content was ablated, in SCD1-inhibited adipocytes. Our data provide evidence that SCD1 has a broad impact on WAT lipid handling by altering TAG composition in a depot-specific manner, reducing FA reesterification, and regulating markers of lipolysis and glyceroneogenesis.

scholarly journals Enhanced soluble sugar content in tomato fruit using CRISPR/Cas9-mediated SlINVINH1 and SlVPE5 gene editing

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e12478
Author(s):  
Baike Wang ◽  
Ning Li ◽  
Shaoyong Huang ◽  
Jiahui Hu ◽  
Qiang Wang ◽  
...  
Keyword(s):  
Gene Editing ◽  
Single Gene ◽  
Tomato Fruit ◽  
Sugar Content ◽  
Soluble Sugar ◽  
Wild Type ◽  
Tomato Fruits ◽  
Knock Out ◽  
Soluble Sugar Content ◽  
Soluble Solid

Soluble sugar is known to improve the sweetness and increase tomato sauce yield. Studies have focused on improving the content of soluble sugar in tomato fruits, usually by promoting functional genes. We studied two genes (SlINVINH1 and SlVPE5) that inhibited the accumulation of soluble sugar in tomato fruits and obtained two genes’ knocked-out lines (CRISPR-invinh1 or CRISPR-vpe5) using CRISPR/Cas9. Aggregated lines with CRISPR-invinh1 and CRISPR-vpe5 were gained by hybridization and self-pollination. Compared to wild-type lines, the glucose, fructose, and total soluble solid (TSS) contents of CRISPR-invinh1 and CRISPR-vpe5 increased significantly. Glucose, fructose, and TSS levels further improved simultaneously with CRISPR-invinh1 and CRISPR-vpe5 than with single gene knock-out lines. This indicates that these genes have a synergistic effect and will increase the soluble sugar content. Thus, the knock-out SlINVINH1 and SlVPE5 may provide a practical basis for improving the sweetness of tomato fruits and their processing quality.

scholarly journals Diurnal down-regulation of ethylene biosynthesis mediates biomass heterosis

2018 ◽  
Vol 115 (21) ◽  
pp. 5606-5611 ◽  
Author(s):  
Qingxin Song ◽  
Atsumi Ando ◽  
Dongqing Xu ◽  
Lei Fang ◽  
Tianzhen Zhang ◽  
...  
Keyword(s):  
Biological Networks ◽  
Ethylene Production ◽  
Molecular Mechanisms ◽  
Ethylene Biosynthesis ◽  
Superior Performance ◽  
F1 Hybrids ◽  
Down Regulation ◽  
Negative Role ◽  
Exogenous Ethylene

Heterosis is widely applied in agriculture; however, the underlying molecular mechanisms for superior performance are not well understood. Ethylene biosynthesis and signaling genes are shown to be down-regulated in Arabidopsis interspecific hybrids. Ethylene is a plant hormone that promotes fruit ripening and maturation but inhibits hypocotyl elongation. Here we report that application of exogenous ethylene could eliminate biomass vigor in Arabidopsis thaliana F1 hybrids, suggesting a negative role of ethylene in heterosis. Ethylene biosynthesis is mediated by the rate-limiting enzyme, 1-aminocyclopropane-1-carboxylate synthase (ACS). Down-regulation of ACS genes led to the decrease of ethylene production, which was associated with the high-vigor F1 hybrids, but not with the low-vigor ones. At the mechanistic level, expression of ACS genes was down-regulated diurnally and indirectly by Circadian Clock Associated 1 (CCA1) during the day and directly by Phyotochrome-Interacting Factor 5 (PIF5) at night. Consistent with the negative role of ethylene in plant growth, biomass vigor was higher in the acs mutants than in wild-type plants, while increasing endogenous ethylene production in the hybridizing parents reduced growth vigor in the hybrids. Thus, integrating circadian rhythms and light signaling into ethylene production is another regulatory module of complex biological networks, leading to biomass heterosis in plants.

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