scholarly journals Update on the Roles of Polyamines in Fleshy Fruit Ripening, Senescence, and Quality

2021 ◽  
Vol 12 ◽  
Author(s):  
Fan Gao ◽  
Xurong Mei ◽  
Yuzhong Li ◽  
Jiaxuan Guo ◽  
Yuanyue Shen
Keyword(s):  
Calcium Ions ◽  
Fruit Ripening ◽  
Arginine Decarboxylase ◽  
Model System ◽  
Polyamine Oxidase ◽  
Fleshy Fruit ◽  
Molecular Processes ◽  
Adenosylmethionine Decarboxylase ◽  
Metabolic Transition ◽  
Made In

Ripening of fleshy fruits involves complex physiological, biochemical, and molecular processes that coincide with various changes of the fruit, including texture, color, flavor, and aroma. The processes of ripening are controlled by ethylene in climacteric fruits and abscisic acid (ABA) in non-climacteric fruits. Increasing evidence is also uncovering an essential role for polyamines (PAs) in fruit ripening, especially in climacteric fruits. However, until recently breakthroughs have been made in understanding PA roles in the ripening of non-climacteric fruits. In this review, we compare the mechanisms underlying PA biosynthesis, metabolism, and action during ripening in climacteric and non-climacteric fruits at the physiological and molecular levels. The PA putrescine (Put) has a role opposite to that of spermidine/spermine (Spd/Spm) in cellular metabolism. Arginine decarboxylase (ADC) is crucial to Put biosynthesis in both climacteric and non-climacteric fruits. S-adenosylmethionine decarboxylase (SAMDC) catalyzes the conversion of Put to Spd/Spm, which marks a metabolic transition that is concomitant with the onset of fruit ripening, induced by Spd in climacteric fruits and by Spm in non-climacteric fruits. Once PA catabolism is activated by polyamine oxidase (PAO), fruit ripening and senescence are facilitated by the coordination of mechanisms that involve PAs, hydrogen peroxide (H2O2), ABA, ethylene, nitric oxide (NO), and calcium ions (Ca2+). Notably, a signal derived from PAO5-mediated PA metabolism has recently been identified in strawberry, a model system for non-climacteric fruits, providing a deeper understanding of the regulatory roles played by PAs in fleshy fruit ripening.

scholarly journals Overexpression of arginine decarboxylase in transgenic plants

1997 ◽  
Vol 325 (2) ◽  
pp. 331-337 ◽  
Author(s):  
Daniel BURTIN ◽  
Anthony J. MICHAEL
Keyword(s):  
Transgenic Plants ◽  
Arginine Decarboxylase ◽  
Polyamine Metabolism ◽  
Morphological Development ◽  
Polyamine Biosynthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Two Generations ◽  
Key Enzyme ◽  
Polyamine Conjugate ◽  
And Control

The activity of arginine decarboxylase (ADC), a key enzyme in plant polyamine biosynthesis, was manipulated in two generations of transgenic tobacco plants. Second-generation transgenic plants overexpressing an oat ADC cDNA contained high levels of oat ADC transcript relative to tobacco ADC, possessed elevated ADC enzyme activity and accumulated 10–20-fold more agmatine, the direct product of ADC. In the presence of high levels of the precursor agmatine, no increase in the levels of the polyamines putrescine, spermidine and spermine was detected in the transgenic plants. Similarly, the activities of ornithine decarboxylase and S-adenosylmethionine decarboxylase were unchanged. No diversion of polyamine metabolism into the hydroxycinnamic acid–polyamine conjugate pool or into the tobacco alkaloid nicotine was detected. Activity of the catabolic enzyme diamine oxidase was the same in transgenic and control plants. The elevated ADC activity and agmatine production were subjected to a metabolic/physical block preventing increased, i.e. deregulated, polyamine accumulation. Overaccumulation of agmatine in the transgenic plants did not affect morphological development.

Towards understanding paternal extragenic contributions to early amphibian pattern specification: the axolotl ts—1 gene as a model system

Development ◽  
1985 ◽  
Vol 89 (Supplement) ◽  
pp. 53-68
Author(s):  
George M. Malacinski ◽  
Dorothy Barone
Keyword(s):  
Genetic Data ◽  
Mutant Gene ◽  
Model System ◽  
Early Embryogenesis ◽  
Ambystoma Mexicanum ◽  
Parental Effects ◽  
Phenotypic Data ◽  
Modes Of Action ◽  
Pattern Specification ◽  
Made In

As a model system for understanding the role sperm extragenic components might play in early embryogenesis the genetics and phenotype of the ts—1 axolotl (Ambystoma mexicanum) mutant gene are reviewed. That mutant gene displays parental effects. It exhibits both maternal (egg-mediated) as well as paternal (sperm-mediated) phenotypic effects. A variety of possible modes of action of the ts—1 gene are reviewed. Comparisons of various precedents to the ts—1 genetic data are made. In addition, novel models which account for the ts—1 phenotypic data are presented.

Inhibitors Influencing Plant Enzymes of the Polyamine Biosynthetic Pathway

1989 ◽  
Vol 44 (1-2) ◽  
pp. 49-54 ◽  
Author(s):  
Marbeth Christ ◽  
Hansruedi Felix ◽  
Jost Harr
Keyword(s):  
Biosynthetic Pathway ◽  
Early Stage ◽  
Arginine Decarboxylase ◽  
Polyamine Biosynthesis ◽  
Polyamine Synthesis ◽  
Adenosylmethionine Decarboxylase ◽  
Stage Of Development ◽  
Decarboxylase Inhibitors ◽  
Plant Enzymes ◽  
To Come

Absract Several enzymes involved in polyamine biosynthesis namely ornithine, arginine and S-adenosylmethionine decarboxylase as well as spermidine synthase, were analyzed in partially purified wheat extracts. For all enzymes effective inhibitors were found. Among them the most interesting was l-aminooxy-3-aminopropane, which inhibited all three decarboxylases. Classical polyamine biosynthesis inhibitors like difluoromethylornithine, difluoromethylarginine. methyl glyoxal bis- (guanylhydrazone) and cyclohexylamine were also inhibitory on plant enzymes. A remarkable difference in the amount of arginine and ornithine decarboxylase existed in wheat. Arginine decarboxylase seems to be more important at least during the early stage of development. Influence of polyamine synthesis inhibitors on polyamine levels is more likely to come from arginine decarboxylase inhibitors. As inhibitors of all essential enzymes involved in plant polyamine biosynthesis were found, the study of the importance of polyamines in plant physiology will be considerably facilitated.

Lessons from Worm Dendritic Patterning

2019 ◽  
Vol 42 (1) ◽  
pp. 365-383 ◽  
Author(s):  
Sharon Inberg ◽  
Anna Meledin ◽  
Veronika Kravtsov ◽  
Yael Iosilevskii ◽  
Meital Oren-Suissa ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Animal Model ◽  
Light And Electron Microscopy ◽  
Dendritic Tree ◽  
Model System ◽  
Model Organisms ◽  
Structural Units ◽  
The Past ◽  
Structural And Functional Properties ◽  
Made In

The structural and functional properties of neurons have intrigued scientists since the pioneering work of Santiago Ramón y Cajal. Since then, emerging cutting-edge technologies, including light and electron microscopy, electrophysiology, biochemistry, optogenetics, and molecular biology, have dramatically increased our understanding of dendritic properties. This advancement was also facilitated by the establishment of different animal model organisms, from flies to mammals. Here we describe the emerging model system of a Caenorhabditis elegans polymodal neuron named PVD, whose dendritic tree follows a stereotypical structure characterized by repeating candelabra-like structural units. In the past decade, progress has been made in understanding PVD's functions, morphogenesis, regeneration, and aging, yet many questions still remain.

scholarly journals Progress on Understanding Transcriptional Regulation of Chloroplast Development in Fleshy Fruit

2020 ◽  
Vol 21 (18) ◽  
pp. 6951
Author(s):  
Ting Jia ◽  
Yuting Cheng ◽  
Imran Khan ◽  
Xuan Zhao ◽  
Tongyu Gu ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Nutritional Quality ◽  
Chloroplast Development ◽  
Food Sources ◽  
Fleshy Fruit ◽  
Human Diet ◽  
Fleshy Fruits ◽  
Substantial Progress ◽  
Dark Green ◽  
Made In

Edible fleshy fruits are important food sources in the human diet. Their yield and nutritional quality have long been considered as breeding targets for improvement. Various developing fleshy fruits with functional chloroplasts are capable of photosynthesis and contribute to fruit photosynthate, leading to the accumulation of metabolites associated with nutritional quality in ripe fruit. Although tomato high-pigment mutants with dark-green fruits have been isolated for more than 100 years, our understanding of the mechanism of chloroplast development in fleshy fruit remain poor. During the past few years, several transcription factors that regulate chloroplast development in fleshy fruit were identified through map-based cloning. In addition, substantial progress has been made in elucidating the mechanisms that how these transcription factors regulate chloroplast development. This review provides a summary and update on this progress, with a framework for further investigations of the multifaceted and hierarchical regulation of chloroplast development in fleshy fruit.

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