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PubMed2026

Genome-wide identification of the superoxide dismutase gene family in Lycium barbarum and their expression profiles under abiotic stress and phytohormone treatment.

BACKGROUND: Superoxide dismutases (SODs) are crucial metalloenzymes that constitute the first line of defense against reactive oxygen species in plants under abiotic stress. Wolfberry (Lycium barbarum) is an economically important medicinal plant with notable stress tolerance, however, a comprehensive genome-wide analysis of its SOD gene family has not yet been performed. RESULTS: We identified ten wolfberry SOD genes (LbaSODs) and classified them into three subfamilies: iron-SODs (Fe-SODs), manganese-SODs (Mn-SODs), and copper/zinc-SODs (Cu/Zn-SODs). Members within each subfamily shared conserved gene structures and motifs. Segmental duplication was the primary driver of LbaSOD expansion, with three paralogous pairs identified. Analysis of cis-regulatory elements in the promoter region revealed a predominance of stress- and hormone-responsive cis-elements, particularly ABA-responsive elements (ABREs) (22 copies) and LTR (17 copies) motifs. Tissue-specific expression profiling revealed that LbaSOD2 and LbaSOD5 expression peaked during early fruit development, whereas LbaSOD6, LbaSOD9, and LbaSOD10 were progressively upregulated through fruit maturation. Under abiotic conditions, Fe-SOD members were markedly suppressed during prolonged drought, whereas LbaSOD9 and LbaSOD10 were rapidly induced in response to salt stress. Among the phytohormone treatments, methyl jasmonate (MeJA) elicited the most pronounced response, with LbaSOD5 expression increasing by approximately 60-fold after 24 hours. Notably, abscisic acid (ABA) triggered an exceptionally strong transcriptional induction of LbaSOD5 (2.5 × 105-fold), LbaSOD10 (6 × 105-fold), and LbaSOD6 (70-fold). In addition, LbaSOD3 and LbaSOD7 transcripts were undetectable in any of the tested conditions. CONCLUSIONS: This study provides the first comprehensive characterization of the LbaSOD gene family and elucidates its hormone- and stress-responsive regulatory landscape, providing a valuable foundation for future functional investigations of LbaSOD genes in abiotic stress adaptation. The extraordinarily strong ABA-mediated induction of specific LbaSOD members, together with their tissue- and stress-specific expression patterns, highlights their potential as targets for genetic improvement of stress tolerance in wolfberry.

Lycium barbarum↗
PubMed2026

Hormone priming and metabolic engineering of phytohormone crosstalk in rice under combined biotic and abiotic stresses: a multi-omics perspective for climate-resilient crop development.

Rice (Oryza sativa L.) is the caloric backbone for more than half of humanity, yet it remains one of the most vulnerable crops to the simultaneous biotic and abiotic stresses exacerbated by climate change. Phytohormone priming and the complex crosstalk networks governed by transcription factor hubs like WRKY, MYB, and NAC serve as the central adaptive mechanism for stress resilience. This review synthesizes how multi-omics integration, including spatial and single-cell transcriptomics, is resolving the molecular architecture of hormonal priming and epigenetic stress memory. We critically evaluate advanced metabolic engineering and genome-editing strategies such as CRISPR-Cas9, base/prime editing, and synthetic gene circuits that enable precision modifications to decouple stress tolerance from historical yield penalties. Furthermore, we discuss the emerging roles of microbiome-assisted priming via synthetic consortia and the application of artificial intelligence and digital twins (continuously updated computational models of crop physiology) for predictive stress management. By integrating these diverse technological pillars, we propose a systems-level roadmap for developing climate-resilient rice cultivars capable of maintaining yield stability across a volatile combinatorial stress landscape. This synthesis provides a framework for translating mechanistic hormonal insights into field-applicable cultivars to ensure global food security.

CRISPR↗
PubMed1991

Phenotypically normal transgenic T-cyt tobacco plants as a model for the investigation of plant gene expression in response to phytohormonal stress.

The tumour-inducing T-DNA gene 4 (T-cyt gene) of the nopaline Ti plasmid pTiC58 was cloned and introduced into tobacco cells by leaf disc transformation using Agrobacterium plasmid vectors. Tobacco shoots exposed to elevated cytokinin levels were unable to develop roots and lacked apical dominance. Using exogenously applied phytohormone manipulations we were able to regenerate morphologically normal transgenic tobacco plants which differed in endogenous cytokinin levels from normal untransformed plants. Although T-cyt gene mRNA levels, as revealed by dot-blot hybridization data, in these rooting plants were only about half those in primary transformed shoots the total amount of cytokinins was much lower than in crown gall tissue or cytokinin-type transformed shoots as reported by others. Nevertheless the cytokinin content in T-cyt plants was about 3 times greater than in control tobacco plants. Elevated cytokinin levels have been shown to change the expression of several plant genes, including some nuclear genes encoding chloroplast proteins. Our results show that the mRNA levels of chloroplast rbcL gene increase in cytokinin-type transgenic tobacco plants as compared with untransformed plants. Data obtained suggest that T-cyt transgenic plants are a good model for studying plant gene activity in different parts of the plant under endogenous cytokinin stress.

Agrobacterium tumefaciens↗
PubMed1996

Phytohormone-regulated beta-amylase gene expression in rice.

The expression of beta-amylase genes in rice (Oryza sativa) and its regulation by phytohormones gibberellic acid (GA) and abscisic acid (ABA) were examined. Upon germination beta-amylase is synthesized de novo in aleurone cells and (GA) is not required. Exogenous addition of GA does not enhance the beta-amylase activity, while ABA inhibits the beta-amylase activity, mRNA accumulation, and the germination of rice seeds. GA can reverse ABA inhibition of beta-amylase expression, but not ABA inhibition of seed germination. Such regulation represents a new interaction of ABA and GA.

Abscisic Acid↗
PubMed2002

Evidence for production of the phytohormone indole-3-acetic acid by cyanobacteria.

The ability of cyanobacteria to produce the phytohormone indole-3-acetic acid (IAA) was demonstrated. A colorimetric (Salkowski) screening of 34 free-living and symbiotically competent cyanobacteria, that represent all morphotypes from the unicellular to the highly differentiated, showed that auxin-like compounds were released by about 38% of the free-living as compared to 83% of the symbiotic isolates. The endogenous accumulation and release of IAA were confirmed immunologically (ELISA) using an anti-IAA antibody on 10 of the Salkowski-positive strains, and the chemical authenticity of IAA was further verified by chemical characterization using gas chromatography-mass spectrometry in Nostoc PCC 9229 (isolated from the angiosperm Gunnera) and in Nostoc 268 (free-living). Addition of the putative IAA precursor tryptophan enhanced IAA accumulation in cell extracts and supernatants. As the genome of the symbiotically competent Nostoc PCC 73102 contains homologues of key enzymes of the indole-3-pyruvic acid pathway, a transaminase and indolepyruvate decarboxylase (IpdC), the putative ipdC gene from this cyanobacterium was cloned and used in Southern blot analysis. Out of 11 cyanobacterial strains responding positively in the Salkowski/ELISA test, ipdC homologues were found in 4. A constitutive and possibly tryptophan-dependent production of IAA via the indole-3-pyruvic acid pathway is therefore suggested. The possible role of IAA in cyanobacteria in general and in their interactions with plants is discussed.

Amino Acid Sequence↗
PubMed2002

A multiplex GC-MS/MS technique for the sensitive and quantitative single-run analysis of acidic phytohormones and related compounds, and its application to Arabidopsis thaliana.

A highly sensitive and accurate multiplex gas chromatography-tandem mass spectrometry (GC-MS/MS) technique is reported for indole-3-acetic acid, abscisic acid, jasmonic acid, 12-oxo-phytodienoic acid and salicylic acid. The optimized setup allows the routine processing and analysis of up to 60 plant samples of between 20 and 200 mg of fresh weight per day. The protocol was designed and the equipment used was chosen to facilitate implementation of the method into other laboratories and to provide access to state-of-the-art analytical tools for the acidic phytohormones and related signalling molecules. Whole-plant organ-distribution maps for indole-3-acetic acid, abscisic acid, jasmonic acid, 12-oxo-phytodienoic acid and salicylic acid were generated for Arabidopsis thaliana (L.) Heynh. For leaves of A. thaliana, a spatial resolution of hormone quantitation down to approximately 2 mm(2) was achieved.

Abscisic Acid↗
PubMed2005

Lack of mycorrhizal autoregulation and phytohormonal changes in the supernodulating soybean mutant nts1007.

Autoregulatory mechanisms have been reported in the rhizobial and the mycorrhizal symbiosis. Autoregulation means that already existing nodules or an existing root colonization by an arbuscular mycorrhizal fungus systemically suppress subsequent nodule formation/root colonization in other parts of the root system. Mutants of some legumes lost their ability to autoregulate the nodule number and thus display a supernodulating phenotype. On studying the effect of pre-inoculation of one side of a split-root system with an arbuscular mycorrhizal fungus on subsequent mycorrhization in the second side of the split-root system of a wild-type soybean (Glycine max L.) cv. Bragg and its supernodulating mutant nts1007, we observed a clear suppressional effect in the wild-type, whereas further root colonization in the split-root system of the mutant nts1007 was not suppressed. These data strongly indicate that the mechanisms involved in supernodulation also affect mycorrhization and support the hypothesis that the autoregulation in the rhizobial and the mycorrhizal symbiosis is controlled in a similar manner. The accumulation patterns of the plant hormones IAA, ABA and Jasmonic acid (JA) in non-inoculated control plants and split-root systems of inoculated plants with one mycorrhizal side of the split-root system and one non-mycorrhizal side, indicate an involvement of IAA in the autoregulation of mycorrhization. Mycorrhizal colonization of soybeans also resulted in a strong induction of ABA and JA levels, but on the basis of our data the role of these two phytohormones in mycorrhizal autoregulation is questionable.

Abscisic Acid↗
PubMed2005

Rhodestrin: a novel indole terpenoid phytohormone from Rhodobacter sphaeroides.

A new phytohormone was isolated as a metabolite of anthranilate photobiotransformation by Rhodobacter sphaeroides OU5. It was identified by MS and NMR ((1)H, (13)C) as an indole terpenoid ester [(2E,4E,6E,8E,10E,12E,14E,16E,18E)24-hydroxy-2,6,10,14,19 pentamethyl tetrecosa-2,4,6,8,10,12,14,16,18 nonenyl-2(hydroxy methyl)-1H-indole-3-carboxylate] and is named as rhodestrin. Rhodestrin at 50 nM: gave positive test in auxin bioassay and initiated more profuse and early rooting in tissue-cultured plants than other auxins at 5 microM.

Biotransformation↗
PubMed1992

Phytohormonal regulation of S-adenosylmethionine synthetase by gibberellic acid in wheat aleurones.

Gibberellic acid (GA3) brought about a 3-fold stimulation of AdoMet synthetase activity in wheat aleurones. At the qualitative level, three isozymes of AdoMet synthetase were observed by DE-52 chromatography in GA3-treated wheat aleurones. In contrast, the control wheat aleurones showed a single isozyme. Thus the phytohormone (GA3, 1 microM) induced two additional isozymes of AdoMet synthetase in wheat aleurones. The activity of all the three isozymes in GA3-treated aleurones was considerably decreased by the simultaneous presence of abscisic acid (ABA, 10 microM). Cycloheximide (20 micrograms/ml) also significantly lowered the levels of the three isozymes of AdoMet synthetase in Ga3-treated aleurones, thereby suggesting the requirement of de-novo protein synthesis for the complete induction of isozymes. However, wheat aleurones excised from embryonated wheat seeds, did not require the application of GA3 for the induction of two additional isozymes of AdoMet synthetase. Apparently, the transport of GA3 from the embryo to aleurones induced two new isozymes of AdoMet synthetase. Three isozymes of AdoMet synthetase were also observed in wheat embryos excised from germinated wheat grains, without exogenous application of GA3. The molecular weight of all the three isozymes of AdoMet synthetase in wheat system is 181,000. The molecular weight of the subunit of the enzyme is 84,000. The dimeric nature of AdoMet synthetase was established by SDS-PAGE analysis of the purified enzyme. In-vitro hybridization of two flanking isozymic peaks I and III by NaCl-freeze-thaw method resulted in the appearance of an additional middle activity peak (isozyme II). However, no additional isozymic peaks were generated when isozymic peaks I and III were individually given a freeze-thaw treatment. Thus the flanking isozymic peaks I and III represent homodimers that differed in their net charge. In contrast, the middle isozymic activity peak II, when subjected to NaCl-freeze-thaw treatments yielded two additional isozymic peaks, I and III, thereby suggesting its heterodimeric nature. We envisage that the three isozymes in GA3-treated wheat aleurone layers are formed by the random dimerization of two classes of enzyme subunits. The two enzyme subunits which differ in their net charge could be the product of two genes of AdoMet synthetase (SAM1 and SAM2). Based on this assumption, we propose that a single isozyme I in water imbibed control wheat aleurones is the product of SAM1 gene of AdoMet synthetase. The occurrence of three isozymes in GA3-treated aleurones could be ascribed to the expression of an alternate gene of AdoMet synthetase (SAM2 gene).(ABSTRACT TRUNCATED AT 400 WORDS)

Chromatography, Liquid↗
PubMed1996

Effect of simulated microgravitation on phytohormones and cell structure of tropical orchids.

When studying the effect of two month clinostating on the phytohormonal system of orchids with different types of shoot system branching and different shoot morphology, it was determined that, as a result of simulated microgravitation, endogenous growth regulators changed less in the species with sympodial branching than in species with monopodial branching and without pseudobulbs. Stimulators prevail in the balance of growth regulators in species of the first type and inhibitors in species of the second type. Besides this, comparative analysis of structural organization of juvenile leaf surface tissue of tested orchids was carried out. Variability of size, number and structure of stomatal organization were found according to species belonging to each branching type after clinostating. Electronic microscope studies show some structural peculiarities of epidermal and mesophilous cells.

Gibberellins↗
PubMed2005

Plant CULLIN-based E3s: phytohormones come first.

CULLIN (CUL)-dependent ubiquitin ligases form a class of structurally related multi-subunit enzymes that control the rapid and selective degradation of important regulatory proteins involved in cell cycle progression and development, among others. Several classes of these E3s are also conserved in plants and genetic analyses, using Arabidopsis thaliana, indicate that they play an important function during plant development and responses to the environment. In this review, we will discuss the molecular composition and function of these enzymes in plants with a major emphasis on phytohormone signal transduction pathways.

Cell Cycle↗
PubMed2005

Effect of the application of benzyladenine pulse on organogenesis, acclimatisation and endogenous phytohormone content in kiwi explants cultured under autotrophic conditions.

In traditional in vitro culture, explants grow enclosed in a non-ventilated vessel at high relative humidity with phytohormones continuously present and sucrose as the main energy source. Under such conditions explant growth is far from normal. In this paper, explants of Actinidia deliciosa were cultured in MS medium supplemented with sucrose, benzyladenine and gibberellic acid under autotrophic conditions in glass boxes flushed with air enriched with 600 microl l(-1) CO(2) for the first 20 days and then transferred to MS medium until the end of the culture period. The effect of benzyladenine was assayed in two regimes of application: in cultures for 20 days in the medium or only 24 h in the presence of benzyladenine with the aim of improving shoot proliferation and acclimatisation. The longest explants were those grown under ventilation and pulsed for 24 h with benzyladenine. These explants also rooted spontaneously, whereas those grown with continuous benzyladenine under ventilation or without ventilation grew and rooted poorly. The highest amount of endogenous isoprenoid cytokinins were found in the longest explants grown under ventilation and pulsed for 24 h with benzyladenine; under these conditions zeatin riboside represented two thirds of the entire cytokinin pool. These explants presented the highest amount of indole-3-acetic acid, while abscisic acid content was high in explants cultured under non-ventilated conditions. No differences were observed between explants cultured under ventilation regardless of their exposure to benzyladenine. The longest explants, which also performed best in acclimatisation, also presented a high indole-3-acetic to abscisic acid ratio.

Abscisic Acid↗
PubMed1998

Phytohormone regulation of isoperoxidases in Catharanthus roseus suspension cultures.

Peroxidase (POD) activity was investigated in Catharanthus roseus cell suspensions cultured under different hormonal conditions. Depletion of 2,4-dichlorophenoxyacetic acid (2,4-D) from the culture medium enhanced POD activity in cells and spent medium. Addition of phytohormones, in particular the auxin 2,4-D, reduced POD activity in medium and cellular compartments and enhanced ionically cell-wall bound POD. The differential modulation of POD is due to hormone effects on synthesis and/or accumulation of POD, rather than on the secretion process. Qualitative analysis showed that 2,4-D, but not cytokinins, regulated the synthesis of a basic isoform. The cytokinin treatment seemed to affect acidic rather than basic isoforms. The presence of basic POD is correlated with the capacity of cells to produce indole alkaloids. The major extracellular basic isoperoxidase was purified to homogeneity from culture medium of Catharanthus roseus cell suspensions. The isolated peroxidase is a haem protein with a M(r) of 33,000 and a pI close to 9. The effect of pH on peroxidase activity was studied using guaiacol as substrate and the optimum pH determined at 25 degrees was 6.0. This enzyme acted on guaiacol, 2,2'-azino-bis-(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), o-dianisidine, o-phenylenediamine (o-PD) and pyrogallol, but had no effect on syringaldazine or coniferyl alcohol substrates.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2005

Regulatory networks of the phytohormone abscisic acid.

Structurally similar to retinoic acid (RA), the phytohormone abscisic acid (ABA) controls many developmental and physiological processes via complicated signaling networks that are composed of receptors, secondary messengers, protein kinase/phosphatase cascades, transcription factors, and chromatin-remodeling factors. In addition, ABA signaling is further modulated by mRNA maturation and stability, microRNA (miRNA) levels, nuclear speckling, and protein degradation. This chapter highlights the identified regulators of ABA signaling and reports their homologues in dicotyledonous and monocotyledonous plants.

Abscisic Acid↗
PubMed2006

[Effects of exogenous phytohormones on hairy root growth and biosynthesis of anthraquinones in the hairy root culture of Polygonum multiflorum].

The effects of exogenous phytohormones on hairy root growth and biosynthesis of anthraquinones in the hairy root cultures of Polygonum multiflorum Thunb. were studied. The results showed that the 2,4-D, NAA and 6-BA all have obvious effects on the growth of hairy root cultures and the biosynthesis of anthraquinones. The growth of hairy root and biosynthesis of anthraquinones were strongly restrained by 2,4-D. However, NAA and 6-BA of appropriate concentration were favourable to hairy root growth and anthraquinones production.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2005

Simultaneous determination of multiple phytohormones in plant extracts by liquid chromatography-electrospray tandem mass spectrometry.

A rapid multiresidue method to quantify three different classes of plant hormones has been developed. The reduced concentrations of these metabolites in real samples with complex matrixes require sensitive techniques for their quantification in small amounts of plant tissue. The method described combines high-performance liquid chromatography with electrospray ionization tandem mass spectrometry. Deuterium-labeled standards were added prior to sample extraction to achieve an accurate quantification of abscisic acid, indole-3-acetic acid, and jasmonic acid in a single run. A simple method of extraction and purification involving only centrifugation, a partition against diethyl ether, and filtration was developed and the analytical method validated in four different plant tissues, citrus leaves, papaya roots, barley seedlings, and barley immature embryos. This method represents a clear advantage because it extensively reduces sample preparation and total time for routine analysis of phytohormones in real plant samples.

Carrier Proteins↗
PubMed2006

Moss biology and phytohormones--cytokinins in Physcomitrella.

Mosses present several advantages for the analysis of phytohormone physiology. Their enormous regeneration capacity, the possibility of controlling their whole life cycle under in vitro culture conditions, as well as the small number of cell types facilitate studies of hormone homeostasis. This review focuses on the metabolism and biosynthesis of cytokinins, mostly summarising data obtained using the moss Physcomitrella patens (Hedw.) B.S.G. which has served as a model system for cytokinin research for many years. A comparison of metabolic differences with respect to seed plants is presented, pointing out an important role of adenosine kinase for the formation of nucleotides during cytokinin interconversion in Physcomitrella. Results on cytokinin biosynthesis in Physcomitrella are summarised with respect to the OVE mutants, which can be considered unique in the plant kingdom due to their strong overproduction of cytokinins. The OVE phenotype is correlated with both increased activity in early stages of cytokinin biosynthesis as well as increased conversion of cytokinin riboside to the base. Cytokinin interconverting reactions can contribute to the increased levels of cytokinins in OVE mutants. Further studies on hormone physiology in moss will help to complete our understanding of hormonal homeostasis by elucidating the situation in an evolutionary early embryophyte.

Adenosine Kinase↗
PubMed2002

A gene encoding a protein modified by the phytohormone indoleacetic acid.

We show that the expression of an indole-3-acetic acid (IAA)-modified protein from bean seed, IAP1, is correlated to the developmental period of rapid growth during seed development. Moreover, this protein undergoes rapid degradation during germination. The gene for IAP1, the most abundant protein covalently modified by IAA (iap1, GenBank accession no. ) was isolated and cloned from bush bean (Phaseolus vulgaris) seeds. The 957-bp sequence encodes a 35-kDa polypeptide. IAA-modified proteins represent a distinct class of conjugated phytohormones and appear in bean to be the major form of auxin in seeds. IAA proteins also are found at other stages of development in bean plants. Our immunological and analytical data suggest that auxin modification of a small class of proteins may be a feature common to many plants.

Amino Acid Sequence↗