Phytohormones of Microalgae: Biological Role and Involvement in the Regulation of Physiological Processes. Pt I. Auxins, Abscisic Acid, Ethylene

2015 ◽  
Vol 17 (3) ◽  
pp. 275-289 ◽  
Author(s):  
E.A. Romanenko ◽  
I.V. Kosakovskaya ◽  
P.A. Romanenko
Author(s):  
Haiyan Zhang ◽  
Liping Zhang ◽  
Yunrui Ji ◽  
Yifen Jing ◽  
Lanxin Li ◽  
...  

Abstract The plant-specific VQ gene family participates in diverse physiological processes but little information is available on their role in leaf senescence. Here, we show that the VQ motif-containing proteins, Arabidopsis SIGMA FACTOR BINDING PROTEIN1 (SIB1) and SIB2 are negative regulators of abscisic acid (ABA)-mediated leaf senescence. Loss of SIB1 and SIB2 function resulted in increased sensitivity of ABA-induced leaf senescence. In contrast, overexpression of SIB1 significantly delayed this process. Moreover, biochemical studies revealed that SIBs interact with WRKY75 transcription factor. Loss of WRKY75 function decreased sensitivity to ABA-induced leaf senescence, while overexpression of WRKY75 significantly accelerated this process. Chromatin immunoprecipitation assays revealed that WRKY75 directly binds to the promoters of GOLDEN 2-LIKE1(GLK1) and GLK2, to repress their expression. SIBs repress the transcriptional function of WRKY75 and negatively regulate ABA-induced leaf senescence in a WRKY75-dependent manner. In contrast, WRKY75 positively modulates ABA-mediated leaf senescence in a GLK-dependent manner. In addition, SIBs inhibit WRKY75 function in ABA-mediated seed germination. These results demonstrate that SIBs can form a complex with WRKY75 to regulate ABA-mediated leaf senescence and seed germination.


Author(s):  
Nicolás E Figueroa ◽  
Thomas Hoffmann ◽  
Klaus Olbricht ◽  
Suzanne R Abrams ◽  
Wilfried Schwab

Abstract Abscisic acid (ABA) is a key hormone in non-climacteric Fragaria spp, regulating multiple physiological processes throughout fruit ripening. Its level increases during ripening, and it promotes fruit (receptacle) development. However, its metabolism in the fruit is largely unknown. We analyzed the levels of ABA and its catabolites at different developmental stages of strawberry ripening in diploid and octoploid genotypes and identified two functional ABA-glucosyltransferases (FvUGT71A49 and FvUGT73AC3) and two regiospecific ABA-8’-hydroxylases (FaCYP707A4a and FaCYP707A1/3). ABA-glucose-ester content increased during ripening in diploid F. vesca varieties but decreased in octoploid F. xananassa. Dihydrophaseic acid content increased throughout ripening in all analyzed receptacles, while 7’-hydroxy-ABA and neo-phaseic acid did not show significant changes during ripening. In the studied F. vesca varieties, the receptacle seems to be the main tissue for ABA metabolism, as the content of ABA and its metabolites in the receptacle was generally 100 times higher than in achenes, respectively. The accumulation patterns of ABA catabolites and transcriptomic data from the literature show that all strawberry fruits produce and metabolize considerable amounts of the plant hormone ABA during ripening, which is therefore a conserved process, but also illustrate the diversity of this metabolic pathway which is species, variety and tissue dependent.


1995 ◽  
Vol 14 (1) ◽  
pp. 23-28 ◽  
Author(s):  
C. -C. Yeh ◽  
H. -S. Tsay ◽  
J. -H. Yeh ◽  
F. -Y. Tsai ◽  
C. -Y. Shih ◽  
...  

2016 ◽  
Vol 18 (2) ◽  
pp. 179-201 ◽  
Author(s):  
K. O. Romanenko ◽  
I. V. Kosakovskaya ◽  
P. O. Romanenko

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e9270
Author(s):  
Mohammed Mujitaba Dawuda ◽  
Weibiao Liao ◽  
Linli Hu ◽  
Jihua Yu ◽  
Jianming Xie ◽  
...  

Cadmium (Cd2 +) is among the toxic non-essential heavy metals that adversely affect plants metabolic processes and the safety of produce. However, plant hormones can improve plant’s tolerance to various stresses. This study investigated the effect of exogenous abscisic acid (ABA) on the biochemical and physiological processes and food safety of cadmium (Cd2 +)-sensitive lettuce genotype (Lüsu). Seedlings were subjected to five treatments: [(i) Control (untreated plants), (ii) 100 µM CdCl2, (iii) 100 µM CdCl2+10 µg L−1 ABA (iv) 10 µg L−1 ABA, and (v) 0.01 g L−1 ABA-inhibitor (fluridone)] for fourteen days in hydroponic system. The 100 µM CdCl2 increased the contents of hydrogen peroxide (H2O2) and malondialdehyde (MDA), decreased photosynthesis and plant biomass. Moreover, it decreased the contents of essential nutrients (except copper) in the leaves but increased the contents of toxic Cd2 + in the leaves and roots of the plants. Foliar application of fluridone (0.01 g L−1) also caused oxidative stress by increasing the contents of H2O2 and MDA. It also decreased the contents of nutrient elements in the leaves of the plants. However, exogenous ABA (10 µg L−1) mitigated the Cd2 +-induced stress, increased antioxidant enzymes activities, photosynthesis and plant biomass under CdCl2 treatment. Remarkably, exogenous ABA increased the contents of essential nutrient elements but decreased the Cd2 + content in leaves under the CdCl2 treatment. Our results have demonstrated that foliar application of ABA mitigates Cd2 + stress and increases the nutritional quality and food safety of Cd2 +-sensitive lettuce genotype under CdCl2 treatment.


Membranes ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 762
Author(s):  
Guzel R. Akhiyarova ◽  
Ruslan S. Ivanov ◽  
Igor I. Ivanov ◽  
Ekaterina I. Finkina ◽  
Daria N. Melnikova ◽  
...  

Lipid transfer proteins (LTPs) participate in many important physiological processes in plants, including adaptation to stressors, e.g., salinity. Here we address the mechanism of this protective action of LTPs by studying the interaction between LTPs and abscisic acid (ABA, a “stress” hormone) and their mutual participation in suberin deposition in root endodermis of salt-stressed pea plants. Using immunohistochemistry we show for the first time NaCl induced accumulation of LTPs and ABA in the cell walls of phloem paralleled by suberin deposition in the endoderm region of pea roots. Unlike LTPs which were found localized around phloem cells, ABA was also present within phloem cells. In addition, ABA treatment resulted in both LTP and ABA accumulation in phloem cells and promoted root suberization. These results suggested the importance of NaCl-induced accumulation of ABA in increasing the abundance of LTPs and of suberin. Using molecular modeling and fluorescence spectroscopy we confirmed the ability of different plant LTPs, including pea Ps-LTP1, to bind ABA. We therefore hypothesize an involvement of plant LTPs in ABA transport (unloading from phloem) as part of the salinity adaptation mechanism.


2021 ◽  
Author(s):  
Mary Taylor

Abstract Overbeek et al. (1954) defined plant hormones as 'regulators produced by plants, which in low concentrations regulate plant physiological processes. Hormones usually move within the plant from a site of production to a site of action'. Plant hormones can exert their influence on tissues in the site of origin/production - mainly meristems and growing fruits - or they can be translocated to sites far removed from their origin/production (Rademacher, 2015). Plant hormones enable plants to react to internal and external stimuli and include auxins, gibberellins, cytokinins, abscisic acid, and ethylene. Brassinosteroids, jasmonates, salicylic acid, polyamines and florigen are currently considered hormones.


2019 ◽  
Vol 25 ◽  
pp. 131-136
Author(s):  
B. A. Kurchii

Abscisic acid (ABA) is a biologically active substance that takes part in the various biochemical and physiological processes in the plants. There is currently limited knowledge about how these biochemical and physiological processes are triggered and regulated by ABA. Dozens of receptors have been described for ABA signaling but there is no any information why does ABA have so many receptors and how they act at the molecular levels. In this connection I would like to stress that not all cell proteins conjugated with ABA necessarily can be represented as hormone-receptors complexes. In this paper I proposed that physiological processes in plants are performed at molecular level by elementary chemical reactions (redox reactions) that trigger the cascade of subsequent reactions and that can be caused by various chemical and physical factors. Gene keys (fragments of polynucleotides, non-protein receptors) and gene locks (start fragment of genes) are also described. Keywords: abscisic acid, free radicals, receptors, gene keys, gene locks.


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