Plant Growth Regulatory Activity Research Articles

Synthesis, Plant Growth Regulatory Activity, and Transcriptome Analysis of Novel Opabactin Analogs.

Abscisic acid (ABA), a phytohormone, and its analogs have been found to enhance plant resistance to various biotic and abiotic stresses, particularly drought, by activating the ABA signaling pathway. This study used a combination of structure-directed design and molecular docking screening methods to synthesize a novel series of opabactin (OP) analogs. Among them, compounds 4a-4d and 5a showed comparable or superior activity to OP in bioassays, including seed germination and seedling growth inhibition in A. thaliana and rice, stomatal closure, and drought resistance in wheat and soybean. Further transcriptome analysis revealed distinct mechanisms of action between compound 4c and iso-PhABA in enhancing drought tolerance in A. thaliana. These findings highlight the application prospect of 4c and its analogs in agricultural cultivation, particularly in drought resistance. Additionally, they provide new insights into the mechanisms by which different ABA receptor agonists enhance drought resistance.

Sativene Sesquiterpenoids from the Plant Endophytic Fungus Bipolaris victoriae S27 and Their Potential as Plant-Growth Regulators.

Thirteen new sativene sesquiterpenoids (1 and 3-14), one new natural product (2), and 16 known compounds (15-30) were isolated from the endophytic fungus Bipolaris victoriae S27. Their structures were elucidated by extensive spectroscopic analysis, NMR and ECD calculations, and X-ray crystal diffractions. Compound 1 represented the first example of sativene sesquiterpenoids with a 6/5/3/5-caged tetracyclic ring system. All obtained compounds were evaluated for their plant-growth regulatory activity. The results showed that 1, 3, 4, 6, 8, 11, 12, 17, 19, 26, and 27 could suppress the growth of Arabidopsis thaliana, while 2, 5, 13, 15, 18, and 25 showed promoting effects. Among them, compound 3 showed the most potent plant-growth inhibitory activity, which is obviously superior to that of the marked herbicide glyphosate.

Bioactive Compounds from the Mushroom-Forming Fungus Chlorophyllum molybdites.

A novel compound (1) along with two known compounds (2 and 3) were isolated from the culture broth of Chlorophyllum molybdites, and three known compounds (4-6) were isolated from its fruiting bodies. The planar structure of 1 was determined by the interpretation of spectroscopic data. By comparing the specific rotation of the compound with that of the analog compound, the absolute configuration of 1 was determined to be R. This is the first time that compounds 2-4 were isolated from a mushroom-forming fungus. Compound 2 showed significant inhibition activity against Axl and immune checkpoints (PD-L1, PD-L2). In the bioassay to examine growth inhibitory activity against the phytopathogenic bacteria Peptobacterium carotovorum, Clavibacter michiganensis and Burkholderia glumae, compounds 2 and 3 inhibited the growth of P. carotovorum and C. michiganensis. In the bioassay to examine plant growth regulatory activity, compounds 1-4 showed a significant regulatory activity on lettuce growth.

Phytoactive Aryl Carbamates and Ureas as Cytokinin-like Analogs of EDU

Ureas, carbamates and oxamates are rather common structural motifs. They are present in both natural and synthetic compounds that exhibit a wide spectrum of biological activity. These derivatives of carbonic and oxalic acids are regularly employed as the basic structural elements in hybrid molecule synthesis, as well as in organic synthesis in general. A series of unsymmetrical hybrid compounds (E1–E4) has been synthesized, with core imidazolidin-2-one and aryl moieties as urea and carbamate derivatives. Plant growth regulatory activity of these compounds was studied with respect to their influence on germination, growth and development of wheat (Triticum aestivum L.) seeds in laboratory and field tests. Their effect on drought resistance concentrations as low as 4 × 10−7 M was established. Compounds E1 and E4 have shown higher growth-regulating activity than standard thidiazuron and CCC.

UWAVE-2000 as an effective equipment for the microwave аssistant synthesis of N, N-diethyl-2-(mesitylamino)-N-benzyl-oxoethanamonium chloride – a compound with plant growth regulating activity

The synthesis of N,N-Diethyl-2-(mesitiylamino)-N-benzyl-oxoethanamonium chloride was carried out by N-alkylation with traditional method and using microwave and ultrasonic activation. The synthesized ionіс compound is characterized by IR, NMR 1H and 13C methods, and its growth-stimulating activity has been tested on Zea Mays L. maize seeds. The synthesis of N,N-Diethyl-2-(mesitilamino)-N-benzyl-oxoethanamonium chloride using unconventional methods such as microwave and ultrasonic activation resulted in higher yields in a shorter period of time than traditional method. The highest yield (98%) was achieved by microwave activation of UWAVE-2000 in a very short time, while in the classical caseit was lower and the reaction time was twenty-four times longer. The synthesized ionic compound positively influenced the germination and growth energy of maize seeds. In samples treated with solution N,N-Diethyl-2-(mesitylamino)-N-benzyl-oxoethanaminium chloride of mould lesions was not so many, so, the treatment of maize seeds with trimecaine benzyl chloride not only stimulates the plant growth, but also prevent fungi mould formation.

Synthesis, Structural Elucidation, Cytotoxic activity and Plant Growth Studies of Some Novel Schiff Base Cobalt(II) and Nickel(II) Complexes of Sulfur/Oxygen and Nitrogen Donor Agents

Eight metal complexes with Schiff base ligands, HL1 [2-{1-(2-fluorophenyl)ethyledene}] hydrazinecarboxamide and HL2 [2-{1-(2-fluorophenyl)ethyledene}] hydrazinecarboxathioamide were synthesized with Co(II) and Ni(II). These were characterized by analytical as well as various spectroscopic techniques like FT-IR, 1H NMR, electronic absorption spectra. The spectral results revealed the formation of octahedral complexes. To determine the concentration of cobalt in Schiff base metal complex flame atomic absorption spectroscopy (FAAS) was done. The accuracy of results was verified by inductively coupled plasma mass spectroscopy (ICP-MS). In vitro cytotoxic activity of the ligands HL1, HL2 and their Schiff base metal complexes was examined, in which A549 (human lung cancer cell line) and L929 (mouse normal fibroblast cell line) were used in the screening test. Among all the synthesized Schiff base ligands and metal complexes, Ni(II) thiosemicarbazone based complex i.e. (Ni (L2)2.2H2O) exhibited a significant cytotoxic effect towards A549 cell line with a mean IC50 value of 36.43 μΜ. Plant growth regulatory activity of the ligands (HL1, HL2) and their metal complexes have also been performed on chick pea plant. The PGR activity of the ligands and their complexes were compared and it was found that the thiosemicarbazone based metal complexes possess higher PGR activity.

Effect of Plant Growth Regulators and Pinching on Growth and Yield of Marigold (Tagetes erecta L.) under Prayagraj Agro Climatic Conditions

The experiment has been conducted to determine the activity of plant  growth regulators and pinching on the  growth and flowering yield of African marigold (Tagetes erecta L.) in the Department of Horticulture, Sam Higginbottom University of Agriculture Technology and Sciences, Prayagraj, (UP) during  Rabi season 2021-2022, nine treatments were included in this trial viz..., T0 Control, T1 GA3 100 PPM + Pinching, T2 GA3 200 PPM + Pinching, T3 Triacontanol 20 ppm + Pinching, T4 Triacontanol 30 ppm + Pinching, T5 Lihocin 2000 ppm + Pinching, T6 Lihocin 4000 ppm + Pinching, T7 NAA 10 ppm + Pinching and T8 NAA 20 ppm + Pinching, were tested in three replications. The experiment of this design was randomized block design. The results has revealed that GA3 treatments and pinching had significant response on the plant height, number of branches per plant, number of leaves per plant, plant spread per plant, days from bud initiation to harvest, days required for flower appearance from transplanting, number of flowers per plant, flower diameter, fresh and dry flower weight, flower yield per plant, flower yield per plot, and flower yield per hectare. The maximum plant height  (76.17cm), number of branches per plant (53.21), plant spread (90.22cm), number of leaves per plant (409.07), flower yield per plant (402.13g/plant), flower yield per plot (1.57kg), and flower yield per hectare (15.67) were recorded in the treatment T2 GA3 200 PPM + Pinching. This treatment showed the best results in vegetative growth and yield production.

A Patent Data Analysis of the Innovation Trends in Biological Control Agent Formulations.

Biological control (i.e., biocontrol) can be defined as the use of microbial inoculants with a direct and purposeful manipulation of natural enemies, potentially replacing harmful pesticides, to control pests, plant pathogens, and weeds. This study concerns patent analysis of biocontrol agent-based formulations. This form of patent analysis encapsulates information that could be used as a reference by researchers in the fields of agriculture and plants, as well as those interested, especially in biocontrol agents for agriculture. The state has been reviewed by introducing what has been patented concerning Biocontrol Agents (BCAs). Four patent databases have been used, and different keywords and related terms to BCAs were used, and patents were searched according to title, abstract, and claims. The search was then filtered regarding publication year, patent families, patent classifications, inventors, applicants, owners, and jurisdictions. During a search, 2371 patent documents were found between 1982 and 2021. The United States was ranked first with 694 patent documents. 2015 was the year with the maximum number of patent documents (278). The patent classification codes reveal that most inventions are intended for biocides, pest repellants or attractants, or plant growth regulators containing or obtained from microorganisms, viruses, microbial fungi, etc. Moreover, they are also intended for biocidal, pest repellant, pest attractant, or plant growth regulatory activities of chemical compounds or preparations, such as fungicides, athropodicides, and nematocides, which are concentrated in most patents. The knowledge clusters and expert driving factors of this patent analysis indicate that the research and development based on the formulation of biocontrol agents are concentrated in most patents.

Plant growth regulatory activity in the phytopathogenic fungus Plectosphaerella melonis strain 502

Aim. To investigate the ability of our phytopathogenic fungal strain 502, earlier preliminarily identified as the phytopathogen Plectosphaerella melonis (syn. Acremonium cucurbitacearum), to have phytotoxic and/or plant growth regulatory activity. Methods. The phytotoxicity of strain 502, was studied by bioassays using the test cultures of corn (Zea mays L.), garden cress (Lepidium sativum L.), cucumber (Cucumis sativus L.), and onion (Allium cepa L.). The cytotoxicity and genotoxicity of the fungus were estimated using the Allium cepa-test. The mitotic index of the, the duration of mitosis phases, and the frequency of aberrant ana-telophases of Allium cepa L. roots meristem was also investigated. For this purpose, strain 502, was grown in the following culture media: synthetic Raulin-Thom medium for 10 days at 26 ± 2 °С. Cell-free filtrate (culture fluid) was used for the study. Ethylene production was quantified in culture filtrate using gas-chromatography meth- od. Ethylene measurement was performed every 7 days during 8 weeks. The determination was carried out using a gas chromatograph «Agilent Technologies 6850» (USA) fitted with a flame ionization detector, using commercial ethylene as a standard for identification and quantification Every experiment had three repeats. The reliability of experimental data was assessed by statistical methods using Statistica 12 (Stat-Soft Inc., USA). Results. Undiluted culture fluid (obtained by growing the fungus on liquid wort) of our strain 502 inhibited the growth of Z. mays seedlings by 14 %, L. sativum seedlings by 18 % (1 : 100 dilution) and stimulated the growth of L. sativum roots by 54 and 41 % (1 : 10 and 1 : 100 dilutions, respectively). The culture fluid, obtained by growing the fungus on Raulin-Thom’s synthetic agar, demonstrated a slight inhibitory effect on the seedlings and roots of L. sativum, and at the dilution of 1 : 1000 stimulated growth by 30 %. Insignificant changes in the mitotic index of the meristem of A. cepa roots were revealed at the effect of the culture fluid of P. melonis, strain 502, diluted at the ratio of 1 : 100 and 1 : 1000. At the same time, the number of cells at the prophase stage decreased 1.7 times (1 : 100 dilution). There is a significant increase in the number of cells at the metaphase stage – 1.3 and 1.4 times (dilution 1 : 100 and 1 : 1000, respectively), the anaphase stage – 2.1 and 1.8 times (dilution 1 : 100 and 1 : 1000, respectively) and the telophase stage – 1.8 times (1 : 100 dilution), as compared with the positive control (culture medium). The frequencies of aberrant ana-telophases in the apical meristems of the initial roots were 5.0 and 2.2 % (at the culture fluid dilution of 1 : 100 and 1 : 1000, respectively). We researched the abil- ity of P. melonis 502 to synthesize ethylene and the highest level of it was registered after 5 weeks of cultivation (111.78 nmol/h g). Conclusions: It was demonstrated by us that the culture fluid of strain 502 showed no phytotoxic effect on roots and seedlings of the investigated cultures, demonstrating the exclusion of phytotoxins from the possible range of effectors. No cytotoxic or genotoxic activity of the culture fluid was observed either. However, the culture fluid altered the dynamics of the cell cycle, in particular, shortened the prophase and stimulated the metaphase, anaphase, and telophase. The culture fluid of the fungus stimulated the growth of L. sativum roots depending on the nutrient medium, where the fungus was grown and cultivated. In particular, when growing the fungus on the liquid wort, the growth was higher by 54 and 41 % (dilution 1 : 10 and 1 : 100, respectively), when growing on synthetic Raulin-Thom’s medium – by 30 %. This demonstrates the ability of strain 502 to possibly synthesize growth promoting substances. Also, we have shown the ability of this strain to synthetize ethylene in vitro (111.78 ± 13.27 nmol/h per g), which can act as virulence factor. We consider the obtained results to be the first stage of the study on the mechanism of the interaction between pathogenic strain 502 and plants.

In vitro growth response of Patchouli (Pogostemon cablin) cultured in medium containing Methylobacterium spp. filtrate

Mass seeds production through micropropagation can support modern agriculture, but this technique is expensive and largely determined by a medium formulation. The addition of synthetic Plant Growth Regulator (PGR) has a residual effect, meanwhile natural PGRs is more secure but expensive. In vitro testing of PGR activity obtained from bacteria was the first step to substituted synthetic PGRs to become nature PGR. Research to observe PGR activity obtained from four strains of Methylobacterium spp that had been analyzed of the capability of PGRs synthesis was done on in vitro patchouli cultured. There are three activities: 1) The sterilized technique of filtrate using filtration techniques, humid heat, and a combination of both; 2) Testing of Methylobacterium spp. from that production of cytokinins and compared its activity with commercial PGRs (BA and zeatin); and 3) auxin (NAA and IAA). The research showed that strain TD-J2 filtrate added to medium was similar to BA activities, and TD-J7 was similar to zeatin. Auxin activity derived from strain TD-J10 showed the capacity to induces root formation. The research result indicates that synthesis PGR derived from Methylobacterium spp. has similar activity with commercial PGRs.

4-lithiosydnone imines: Generation and stability. Plant growth regulating activity of 4-hydroxymethyl derivatives of sydnone imines

The C(4)-deprotonation of N6-substituted sydnone imines with lithium hexamethyldisilazide (LHDMS), lithium diisopropylamide (LDA), lithium diethylamide (LDEA), and n-BuLi was studied. A thermal stability of 4-lithiosydnone imines was investigated and an efficiency of subsequent reactions of the generated C(4)-lithio derivatives with electrophiles was shown to depend on the exploited deprotonating reagent. It was found that 4-(α-arylhydroxymethyl)sydnone imines, when used for pre-sowing treatment of corn seeds at very low doses (0.25-5 g t−1), promoted a plant growth up to 60%.

Silver nanoparticles as the sterilant in large-scale micropropagation of chrysanthemum

Micropropagation has proven to be an effective method for large-scale plant production in a short time and a useful tool for plant breeding. Microbial contamination is one of the most difficult micropropagation challenges, resulting in reduced plant quality and loss of valuable stocks. Therefore, sterilization of culture media is a critical step in plant micropropagation. However, sterilized media might reduce the activity of plant growth regulators and nutritional components of culture media. The sterilization effects of silver nanoparticles (AgNP) on the growth of explants and culture media were examined. The treatment with 250 ppm AgNP for 15 to 20 min of 4-wk-old ex vitro leaves proved optimal for controlling the contamination. Furthermore, the Murashige and Skoog medium containing 4 ppm AgNP resulted in 100% medium disinfection (no contamination) after 4 wk of culture. The plantlets obtained from non-sterilized MS medium (NoM) containing 4 ppm AgNP and 4 g L−1 agar gave similar results as the control medium with 8 g L−1 agar and the absence of AgNP. Large scale culture systems using NoM in large plastic containers of two different sizes (NoM1 and NoM2) could produce quality plantlets. Chrysanthemum plantlets in the NoM1 system showed higher antioxidant enzyme activities of ascorbate peroxidase and superoxide dismutase than plantlets in the autoclaved medium. Furthermore, the plantlets from NoM were better acclimatized under greenhouse conditions than those from the autoclaved medium (AuM) system. The developmental stages (flower buds and blooming time) of NoM1 and NoM2 plantlets, were 1 wk earlier than those from the AuM system. The successful use of AgNP as a sterilizer and as a component of culture media would reduce the cost of micropropagation and improve plants' quality.

Synthesis, Characterization, and Encapsulation of Novel Plant Growth Regulators (PGRs) in Biopolymer Matrices.

Novel plant growth regulators (PGRs) based on the derivatives of dehydroamino acids 2,3-dehydroaspartic acid dimethyl ester (PGR1), Z-isomer of the potassium salt of 2-amino-3-methoxycarbonylacrylic acid (PGR2) and 1-methyl-3-methylamino-maleimide (PGR3) have been synthesized and their growth-regulating properties investigated. Laboratory testing revealed their plant growth-regulating activity. PGR1 showing the most stimulating activity on all laboratory tested cultures were used in field experiments. Results showed that PGR1 is a highly effective environmentally friendly plant growth regulator with effects on different crops. Biopolymeric microcapsule formulations (chitosan/alginate microcapsule loaded with PGR) suitable for application in agriculture were prepared and characterized. Physicochemical properties and release profiles of PGRs from microcapsule formulations depend on the molecular interactions between microcapsule constituents including mainly electrostatic interactions and hydrogen bonds. The differences in the microcapsule formulations structure did not affect the mechanism of PGRs release which was identified as diffusion through microcapsules. The obtained results opened a perspective for the future use of microcapsule formulations as new promising agroformulations with a sustained and target release for plant growth regulation.

Green Synthesis, Antioxidant, and Plant Growth Regulatory Activities of Novel α-Furfuryl-2-alkylaminophosphonates.

A series of novel α-furfuryl-2-alkylaminophosphonates have been efficiently synthesized from the one-pot three-component classical Kabachnik–Fields reaction in a green chemical approach by addition of an in situ generated dialkylphosphite to Schiff’s base of aldehydes and amines by using environmental and eco-friendly silica gel supported iodine as a catalyst by microwave irradiation. The advantage of this protocol is simplicity in experimental procedures and products were resulted in high isolated yields. The synthesized α-furfuryl-2-alkylaminophosphonates were screened to in vitro antioxidant and plant growth regulatory activities and some are found to be potent with antioxidant and plant growth regulatory activities. These in vitro studies have been further supported by ADMET (absorption, distribution, metabolism, excretion, and toxicity), quantitative structure–activity relationship, molecular docking, and bioactivity studies and identified that they were potentially bound to the GLN340 amino acid residue in chain C of 1DNU protein and TYR597 amino acid residue in chain A of 4M7E protein, causing potential exhibition of antioxidant and plant growth regulatory activities. Eventually, title compounds are identified as good blood–brain barrier (BBB)-penetrable compounds and are considered as proficient central nervous system active and neuroprotective antioxidant agents as the neuroprotective property is determined with BBB penetration thresholds.

Itaconic acid derivatives: structure, function, biosynthesis, and perspectives

Itaconic acid possessing a vinylidene group, which is mainly produced by fungi, is used as a biobased platform chemical and shows distinctive bioactivities. On the other hand, some fungi and lichens produce itaconic acid derivatives possessing itaconic acid skeleton, and the number of the derivatives is currently more than seventy. Based on the molecular structures, they can be categorized into two groups, alkylitaconic acids and α-methylene-γ-butyrolactones. Interestingly, some itaconic acid derivatives show versatile functions such as antimicrobial, anti-inflammatory, antitumor, and plant growth-regulating activities. The vinylidene group of itaconic acid derivatives likely participates in these functions. It is suggested that α-methylene-γ-butyrolactones are biosynthesized from alkylitaconic acids which are first biosynthesized from acyl-CoA and oxaloacetic acid. Some modifying enzymes such as hydroxylase and dehydratase are likely involved in the further modification after biosynthesis of their precursors. This contributes to the diversity of itaconic acid derivatives. In this review, we summarize their structures, functions, and biosynthetic pathways together with a discussion of a strategy for the industrial use. KEY POINTS: • Itaconic acid derivatives can be categorized into alkylitaconic acids and α-methylene-γ-butyrolactones. • The vinylidene group of itaconic acid derivatives likely participates in their versatile function. • It is suggested that α-methylene-γ-butyrolactones are biosynthesized from alkylitaconic acids which are first synthesized from acyl-CoA and oxaloacetic acid.

Chemical profile and phytotoxic action of Onopordum acanthium essential oil.

The potential of utilizing Onopordum acanthium essential oil and its major constituents as environment friendly herbicides was investigated. In total 29, 25, and 18 compounds were identified from flower, leaf, and stem oils, representing 94.77%, 80.02%, and 90.74% of the total oil, respectively. Flower and stem oils were found to be rich in n-alkanes, which accounted for 57.33% in flower oil, and 82.33% in stem oil. Flower oil exerted potent inhibitory activity on both receiver species, Amaranthus retroflexus and Poa annua, which nearly completely suppressed seed germination at 5 mg/mL, and β-eudesmol is the most likely responsible compound for its phytotoxicity; in comparison, leaf and stem oils exhibited much weaker inhibitory activity on A. retroflexus, and stimulatory effect on P. annua when tested concentration was below 2.5 mg/mL. Alkanes in the oils were found to exert relatively weak plant growth regulatory activity. This report is the first on the chemical profile and phytotoxic action of O. acanthium oil as well as the phytotoxicity of β-eudesmol.

Secondary Metabolites with Plant Growth Regulator Activity Produced by an Endophytic Fungus Purpureocillium sp. from Solanum rostratum

Secondary Metabolites with Plant Growth Regulator Activity Produced by an Endophytic Fungus Purpureocillium sp. from Solanum rostratum

Mathematical Modeling of Biological Activity of Plant Growth Regulators

The paper dwells upon asymmetrical triazines as plant growth regulators. It presents in vitro and in vivo tests of 1,2,4-triazine compounds. The authors have developed a mathematical model to predict growth promotion, which serves as the basis of the proposed algorithm for projecting the biological efficacy of nitrogen-containing heterocycles.

Advances in new multicomponent crystal system: structure, thermal kinetic analysis, photoluminescent, and biological activity investigations

Multicomponent organic crystals based on natural metabolites or pharmaceutical active ingredients play an important role in solid state chemistry, agriculture, and pharmaceutical industry. This study reveals the synthesis of a new luminescent alkanolammonium salt of 4-nitrobenzoic acid (MMEA4NB, methylethanolammonium 4-nitrobenzoate), together with the detailed investigation of its structural motifs, thermal stability, decomposition kinetics, and validation of its plant growth regulatory activity. The new compound was obtained at room temperature in excellent yield and shorter reaction time. Thermal stability and decomposition were studied in a dynamic air atmosphere by thermogravimetry—differential thermal analysis—derivative thermogravimetric techniques. The kinetics and mechanism of the thermal decomposition reaction were evaluated under non-isothermal conditions using three different isoconversional methods Flynn–Wall and Ozawa, Friedman, and modified nonparametric kinetics method in order to obtain the activation energy. Proton transfer and hydrogen bonding in the organic salt were elucidated and confirmed by infrared spectroscopy and single-crystal X-ray diffraction. The crystal structure revealed cation–anion heterosynthons and cation–cation homosynthon. The relation between the protonation state of the components, intermolecular interactions, and thermal stability of MMEA4NB is discussed. This study demonstrates the importance of MMEA4NB in the development of new specific luminescent plant growth regulators, possible viewers of localization and distribution in plants.

Field evaluation of preemergence activity of plant growth regulators on annual bluegrass

Field evaluation of preemergence activity of plant growth regulators on annual bluegrass