306 DECREASED ETHYLENE SYNTHESIS AND ALTERED FRUIT RIPENING IN TRANSGENIC TOMATOES EXPRESSING S-ADENOSYLMETHIONINE HYDROIASE

The gene encoding S-adenosylmethionine hydrolase (SAMase) was transferred to tomato (Lycopersicon esculentum, cv. large red cherry) as a means of reducing ethylene biosynthesis in the ripening fruit. S-adenosylmethionine (SAM), the penultimate precursor to ethylene in plants. is converted to methylthioadenosine and homoserine by SAMase thereby reducing the capacity of the transgenic plant to synthesize ethylene. We have used both constitutive and fruit-specific tomato promoters to regulate SAMase gene expression. Whereas the constitutive CaMV 35S:SAMase chimeric gene expressed active SAMase and conferred a 50-60% reduction in ethylene biosynthesis in a leaf disc assay, there was little effect on fruit ethylene synthesis or postharvest ripening physiology. The use of either the tomato E4 or E8 promoters restricted SAMase expression to ripening fruit which caused a substantial (80-90%) reduction in fruit ethylene synthesis and a profound effect on fruit ripening. SAMase expression levels reached 0.1% of total cellular protein as measured on western blots using anti-SAMase monoclonal antibodies. Field trial fruit picked al the mature green stage accumulated less lycopene and were twice as firm as controls over a six week period. Vine-ripened fruit had near-normal levels of lycopene, were firmer at harvest than controls, and did not lose firmness over a two week period. Taste, vitamin content and tomatine content were superior or equivalent to control tomatoes.

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Identification of a Gene Encoding Glutamate Decarboxylase Involved in the Postharvest Fruit Ripening Process in Banana

HortScience ◽

10.21273/hortsci.49.8.1056 ◽

2014 ◽

Vol 49 (8) ◽

pp. 1056-1060 ◽

Cited By ~ 4

Author(s):

Wei Hu ◽

Ju-Hua Liu ◽

Xiao-Ying Yang ◽

Jian-Bin Zhang ◽

Cai-Hong Jia ◽

...

Keyword(s):

Fruit Ripening ◽

Ethylene Production ◽

Glutamate Decarboxylase ◽

Ethylene Biosynthesis ◽

Gene Encoding ◽

Ripening Process ◽

Climacteric Fruit ◽

Genes Encoding ◽

Postharvest Ripening ◽

Exogenous Ethylene

The banana, a typical climacteric fruit, undergoes a postharvest ripening process followed by a burst in ethylene production that signals the beginning of the climacteric period. Postharvest ripening plays an important role in improving the quality of the fruit as well as limiting its shelf life. To investigate the role of glutamate decarboxylase (GAD) in climacteric ethylene biosynthesis and fruit ripening in postharvest banana, a GAD gene was isolated from banana, designated MuGAD. Coincidently with climacteric ethylene production, MuGAD expression as well as the expression of the genes encoding the Musa 1-aminocyclopropane-1-carboxylate synthase (MaACS1) and Musa 1-aminocyclopropane-1-carboxylate oxidase (MaACO1) greatly increased during natural ripening and in ethylene-treated banana. Moreover, ethylene biosynthesis, ripening progress, and MuGAD, MaACS1, and MaACO1 expression were enhanced by exogenous ethylene application and inhibited by 1-methylcyclopropene (1-MCP). Taken together, our results suggested that MuGAD is involved in the fruit ripening process in postharvest banana.

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Exogenous Application of Sucrose Promotes Postharvest Ripening of Kiwifruit

Agronomy ◽

10.3390/agronomy10020245 ◽

2020 ◽

Vol 10 (2) ◽

pp. 245 ◽

Cited By ~ 1

Author(s):

Liuying Fei ◽

Xin Yuan ◽

Chuying Chen ◽

Chunpeng Wan ◽

Yongqi Fu ◽

...

Keyword(s):

Fruit Ripening ◽

Sucrose Accumulation ◽

Ethylene Synthesis ◽

Sucrose Transport ◽

Ripening Process ◽

Ethylene Content ◽

Sugar Signal ◽

Postharvest Ripening ◽

Fruit Flavor ◽

Ethylene Signal

Sucrose is an important component of fruit flavor, but whether sucrose signaling affects the postharvest ripening process of kiwifruit is unclear. The aim of this article was to study the effect of sucrose application on postharvest kiwifruit ripening to clarify the effect of sucrose in this process. Our present study found that exogenous sucrose can promote ethylene synthesis, which increases the ethylene content during fruit ripening, thereby accelerating the ripening and softening of kiwifruit after harvest. A significantly higher expression of AcACS1 and AcACO2 was found in sucrose-treated fruits compared to that in mannitol-treated fruits. Blocking the ethylene signal significantly inhibited the sucrose-modulated expression of most selected ripening-related genes. Sucrose transport is essential for sucrose accumulation in fruits; therefore, we isolated the gene family related to sucrose transport in kiwifruit and analyzed the gene expression of its members. The results show that AcSUT1 and AcTST1 expression increased with fruit ripening and AcSUT4 expression decreased with ripening, indicating that they may have different roles in the regulation of fruit ripening. Additionally, many cis-elements associated with phytohormones and sugar responses were found in the promoter of the three genes, which suggests that they were transcriptionally regulated by sugar signal and phytohormones. This study demonstrates the effect of sucrose on postharvest ripening of kiwifruit, providing a good foundation for further research.

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Auxin-Induced SaARF4 Downregulates SaACO4 to Inhibit Lateral Root Formation in Sedum alfredii Hance

International Journal of Molecular Sciences ◽

10.3390/ijms22031297 ◽

2021 ◽

Vol 22 (3) ◽

pp. 1297

Author(s):

Dong Xu ◽

Zhuchou Lu ◽

Guirong Qiao ◽

Wenmin Qiu ◽

Longhua Wu ◽

...

Keyword(s):

Lateral Root ◽

Ethylene Biosynthesis ◽

Luciferase Assay ◽

Sedum Alfredii ◽

Ethylene Synthesis ◽

Root Tips ◽

Sedum Alfredii Hance ◽

Auxin Distribution ◽

Distribution Mode ◽

High Level

Lateral root (LR) formation promotes plant resistance, whereas high-level ethylene induced by abiotic stress will inhibit LR emergence. Considering that local auxin accumulation is a precondition for LR generation, auxin-induced genes inhibiting ethylene synthesis may thus be important for LR development. Here, we found that auxin response factor 4 (SaARF4) in Sedum alfredii Hance could be induced by auxin. The overexpression of SaARF4 decreased the LR number and reduced the vessel diameters. Meanwhile, the auxin distribution mode was altered in the root tips and PIN expression was also decreased in the overexpressed lines compared with the wild-type (WT) plants. The overexpression of SaARF4 could reduce ethylene synthesis, and thus, the repression of ethylene production decreased the LR number of WT and reduced PIN expression in the roots. Furthermore, the quantitative real-time PCR, chromatin immunoprecipitation sequencing, yeast one-hybrid, and dual-luciferase assay results showed that SaARF4 could bind the promoter of 1-aminocyclopropane-1-carboxylate oxidase 4 (SaACO4), associated with ethylene biosynthesis, and could downregulate its expression. Therefore, we concluded that SaARF4 induced by auxin can inhibit ethylene biosynthesis by repressing SaACO4 expression, and this process may affect auxin transport to delay LR development.

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Evaluation of powdery mildew resistance in various melon (Cucumis melo L.) genotypes

Agricultural Science and Technology ◽

10.15547/10.15547/ast.2018.04.053 ◽

2018 ◽

Vol 10 (4) ◽

pp. 279-284

Author(s):

Zh. Ivanova ◽

K. Vasileva ◽

N. Velkov ◽

S. Grozeva

Keyword(s):

Powdery Mildew ◽

Genetic Resistance ◽

Leaf Disc ◽

Breeding Program ◽

Vegetable Crops ◽

Plant Materials ◽

South Central ◽

Leaf Disc Assay ◽

Disc Assay

Abstract. Powdery mildew, caused by Podosphaera xanthii and Golovinomyces cichoracearum, is an economically important disease in melon worldwide. Genetic resistance is one of the most suitable strategies to control powdery mildew. During the last few years several races of the pathogens have been reported. The need to develop resistant varieties is a challenge for each breeding program. Leaf disc assay was used in phytopathology and breeding programs as a rapid and reliable method for evaluation of disease resistance in a large number of plant materials. The purpose of this study was to establish species and races of powdery mildew in Plovdiv region, South Central Bulgaria; to develop a suitable system of pathogen isolation and cultivation; to determine the resistance levels in different melon genotypes available in Maritsa Vegetable Crops Research Institute (MVCRI) - Plovdiv collection by the leaf disc assay. Fifty-three melon genotypes, including lines, varieties, hybrids and ten differential lines were tested. The data showed that causal agent of powdery mildew was race 1 of P. xanthii in Plovdiv region. Our experimental results indicated that for the long-term storage of powdery mildew it is preferable to keep a whole plant under in vitro conditions. This allows the preservation of powdery mildew for two months before transferring on a new tissue. Thirty-four of the tested melon genotypes reacted as immune or resistant and nineteen as susceptible. Resistant melon genotypes are a suitable source in initiating a new breeding program aimed to increase resistance to powdery mildew.

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Altered Gene Expression, Leaf Senescence, and Fruit Ripening by Inhibiting Ethylene Synthesis with EFE-Antisense Genes

Cellular and Molecular Aspects of the Plant Hormone Ethylene - Current Plant Science and Biotechnology in Agriculture ◽

10.1007/978-94-017-1003-9_15 ◽

1993 ◽

pp. 82-89 ◽

Cited By ~ 2

Author(s):

J. E. Gray ◽

S. Picton ◽

R. Fray ◽

A. J. Hamilton ◽

H. Smith ◽

...

Keyword(s):

Gene Expression ◽

Leaf Senescence ◽

Fruit Ripening ◽

Ethylene Synthesis ◽

Altered Gene Expression ◽

Altered Gene ◽

Antisense Genes

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NAC transcription factors play an important role in ethylene biosynthesis, reception and signaling of tomato fruit ripening

Molecular Genetics and Genomics ◽

10.1007/s00438-016-1177-0 ◽

2016 ◽

Vol 291 (3) ◽

pp. 1205-1217 ◽

Cited By ~ 30

Author(s):

Xiaohong Kou ◽

Chen Liu ◽

Lihua Han ◽

Shuang Wang ◽

Zhaohui Xue

Keyword(s):

Transcription Factors ◽

Fruit Ripening ◽

Tomato Fruit ◽

Ethylene Biosynthesis ◽

Nac Transcription Factors ◽

Tomato Fruit Ripening

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A Non-Climacteric Fruit Gene CaMADS-RIN Regulates Fruit Ripening and Ethylene Biosynthesis in Climacteric Fruit

PLoS ONE ◽

10.1371/journal.pone.0095559 ◽

2014 ◽

Vol 9 (4) ◽

pp. e95559 ◽

Cited By ~ 15

Author(s):

Tingting Dong ◽

Guoping Chen ◽

Shibing Tian ◽

Qiaoli Xie ◽

Wencheng Yin ◽

...

Keyword(s):

Fruit Ripening ◽

Ethylene Biosynthesis ◽

Climacteric Fruit

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

Journal of Experimental Botany ◽

10.1093/jxb/eraa131 ◽

2020 ◽

Vol 71 (12) ◽

pp. 3560-3574 ◽

Cited By ~ 7

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.

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Shikimate Accumulation in Sunflower, Wheat, and Proso Millet after Glyphosate Application

Weed Science ◽

10.1614/ws-06-065.1 ◽

2007 ◽

Vol 55 (1) ◽

pp. 1-5 ◽

Cited By ~ 30

Author(s):

W. Brien Henry ◽

Dale L. Shaner ◽

Mark S. West

Keyword(s):

Leaf Disc ◽

Spectrophotometric Assay ◽

The Other ◽

Proso Millet ◽

Glyphosate Drift ◽

Leaf Disc Assay ◽

Disc Assay

Experiments were conducted to examine the utility of a spectrophometric leaf disc assay for detecting shikimate accumulation after glyphosate application in sunflower, proso millet, and wheat. The assay was conducted on both greenhouse- and field-grown plants. Glyphosate was applied at five rates ranging from 840 to 53 g ae ha−1. Shikimate accumulation data were generated at 1, 4, 7, and 14 d after application (DAA). Sunflower accumulated shikimate more rapidly and at lower glyphosate rates than the other two species. At 14 DAA, glyphosate at the two highest rates remained detectable in all three species. Plants receiving lower glyphosate doses (210, 105, and 53 g ae ha−1) had begun to grow out of the injury, or at least the shikimate levels in the plants were no longer significantly different than that present in the untreated controls. This spectrophotometric assay is both rapid and simple, with respect to other means of detecting shikimate, and it can be used to detect glyphosate drift. For it to be used by crop managers, samples from potentially drift-affected crops should be taken as soon as possible after the suspected drift event or immediately after the appearance of glyphosate injury.

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