Thidiazuron combined with cyclanilide modulates hormone pathways and ROS systems in cotton, increasing defoliation at low temperatures.

Low temperatures decrease the thidiazuron (TDZ) defoliation efficiency in cotton, while cyclanilide (CYC) combined with TDZ can improve the defoliation efficiency at low temperatures, but the mechanism is unknown. This study analyzed the effect of exogenous TDZ and CYC application on cotton leaf abscissions at low temperatures (daily mean temperature: 15°C) using physiology and transcriptomic analysis. The results showed that compared with the TDZ treatment, TDZ combined with CYC accelerated cotton leaf abscission and increased the defoliation rate at low temperatures. The differentially expressed genes (DEGs) in cotton abscission zones (AZs) were subjected to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses to compare the enriched GO terms and KEGG pathways between the TDZ treatment and TDZ combined with CYC treatment. TDZ combined with CYC could induce more DEGs in cotton leaf AZs at low temperatures, and these DEGs were related to plant hormone and reactive oxygen species (ROS) pathways. CYC is an auxin transport inhibitor. TDZ combined with CYC not only downregulated more auxin response related genes but also upregulated more ethylene and jasmonic acid (JA) response related genes at low temperatures, and it decreased the indole-3-acetic acid (IAA) content and increased the JA and 1-aminocyclopropane-1-carboxylic acid (ACC) contents, which enhanced cotton defoliation. In addition, compared with the TDZ treatment alone, TDZ combined with CYC upregulated the expression of respiratory burst oxidase homologs (RBOH) genes and the hydrogen peroxide content in cotton AZs at low temperatures, which accelerated cotton defoliation. These results indicated that CYC enhanced the TDZ defoliation efficiency in cotton by adjusting hormone synthesis and response related pathways (including auxin, ethylene, and JA) and ROS production at low temperatures.

Cannabis sativa L. from Seized Drug Material: In Vitro Germination and Establishment.

Background: With the expansion of the cannabis-derived product market, there is a growing need for seedling development to produce raw material for pharmaceutical applications and medicinal research. However, cannabis cultivation is illegal in many countries, and legal producers do not sell cannabis seeds in these countries. In Brazil, cannabis is still illegal, and the only way to obtain access to cannabis plants for research or as medicine is through importation, which is costly and requires authorization from the National Health Surveillance Agency (ANVISA), or from material seized by the police from drug trafficking. Methods: Therefore, since cannabis seeds obtained from drug trafficking have never been tested regarding their viability and use in in vitro cultivation, the aim of this study was to analyze the in vitro establishment of cannabis from seeds derived from Brazilian drug trafficking seizures that were provided by the police to investigate seed disinfestation procedures and further multiplication of nodal segments, with the purpose of obtaining material for medicinal research in the country. Seeds were subjected to four disinfestation treatments. Results: The best disinfestation treatment consisted in submerging the seeds in a 2 g·L-1 Captan® solution for 30 min before following the standard procedure with 70% ethanol for 30 sec and then 20 min in 2.5% sodium hypochlorite. The in vitro establishment of cannabis from seeds originating from Brazilian drug trafficking seizures was successful. The germination rate ranged from 10% to 90% according to the sample material. Non-brick weed, which consisted of dry leaves, stalks, and flowers, was more suitable for seed extraction and germination. Clones originating from BW4b showed the best development results compared with others. Conclusions: This is the first report of in vitro cannabis use in Brazil and opens great prospects for future work on its cultivation and research for medicinal applications in the country without relying on seed importation.

Miniaturized extraction and determination of swelling agents in fruits and vegetables based on deep eutectic solvent-molecularly imprinted hydrophilic resin.

The overuse of swelling agents in fruits and vegetables has rapidly increased, resulting in food safety problems. Hence, a new method for the selective extraction and detection of thidiazuron (TDZ) and forchlorfenuron (KT30) was developed using deep eutectic solvent-molecularly imprinted hydrophilic resin (DES-MIHR) as a pipette tip solid-phase extraction (PT-SPE) adsorbent with excellent molecular recognition in aqueous matrixes. DES-MIHR interacted with TDZ and KT30 via π-π interactions and hydrogen bonding. The miniaturized PT-SPE can be performed with just 5.0 mg adsorbent, 0.3 mL water, and 0.2 mL eluent, thus having the advantage of the low consumption of adsorbent and organic reagents. The performance of the DES-MIHR-PT-SPE-high-performance liquid chromatography (HPLC) method was demonstrated with the recoveries from various fruits and vegetables being 81.1-102.9 % (RSD ≤ 7.1 %). Thereby indicating the general applicability of the developed method for the accurate determination of trace swelling agents in fruits and vegetables.

First Report on Mesophyll Protoplast Isolation and Regeneration System for the Duboisia Species.

The Duboisia species, a group of plants native to Australia, have been historically valued for their pharmacological properties and have played a significant role in traditional medicine and pharmaceutical research. Persistent efforts are underway to enhance the efficacy of the active ingredient scopolamine, employing both conventional breeding methods and advanced biotechnology tools. The primary objective of this research was to establish a highly efficient method for isolating mesophyll protoplasts and facilitating their regeneration, thereby laying a robust foundation for the application of various advanced plant biotechnology tools in the pursuit of genetic enhancement. The mesophyll protoplast isolation process was developed for hybrid D. myoporoides × D. hopwoodii with careful optimisation of the following parameters: leaf strip size; incubation conditions; physical treatment; and enzyme concentration. The optimal parameters were combined in each individual step; the best enzyme concentration was determined to be 2% (w/v) cellulysin and 0.5% (w/v) macerase. Protoplast yield was found to be greatly affected by the enzyme concentrations. The isolated protoplasts were cultured at a density of 0.5 × 105 to best sustain the highest cell division (33.2%) and a microcalli induction frequency of 17.9%. After 40 days of culture in a modified KM8P medium at 25 °C in darkness, visible microcalli were transferred to a solidified Murashige and Skoog (MS) medium with 1 mg L-1 2,4-dichlorophenoxyacetic acid (2,4-D) for callus induction under a 16 h photoperiod. After 30 days of culture, compact organogenic calli were transferred into a solid MS medium with 6-benzylaminopurine (BA) alone or thidiazuron (TDZ) alone or in combination with BA or naphthalene acetic acid (NAA) for shoot regeneration. The maximum shoot regeneration frequency (63.3%) was observed in the medium with 1.5 mg L-1 TDZ alone. For the first time, a reliable protoplast isolation and regeneration system from mesophyll cells was established for Duboisia with high protoplast viability, successful microcalli formation, and intact plant regeneration. This innovation will significantly contribute towards the genetic enhancement of the Duboisia species.

Callus induction and regeneration in high-altitude Himalayan rice genotype SR4 via seed explant.

SR4 genotype of rice is high altitude Himalayan rice prone to various abiotic stresses such as cold stress and therefore gives a poor yield. An efficient protocol for callusing and regeneration via direct and indirect means was established using mature seeds as an explant which can be utilized for molecular studies for genetic advancement of Himalayan rice genotype SR4 through transformation. Highest frequency (96.6%) of callus induction was obtained on MS media 3.0 mg/L 2, 4-D. While maximum regeneration frequency (100%), number of shoots with maximum length 9.14 ± 0.204 (cm) from callus was recovered from MS media amended with 5.0 mg/L BAP in combination with 0.5 mg/L NAA with highest number of shoots having an average shoot length 9.14 ± 0.204 (cm) after four weeks of culture. Direct multiple shoot regeneration from seed explants was obtained using various concentrations of TDZ and BAP with highest regeneration frequency was observed on MS media fortified with 6 mg/L of TDZ with maximum number of shoots. The shoots developed roots on MS media supplemented with 0.6 mg/L IBA.

Thidiazuron, a phenyl-urea cytokinin, inhibits ergosterol synthesis and attenuates biofilm formation of Candida albicans.

Candida albicans is a common human fungal pathogen that colonizes mucosa and develops biofilm in the oral cavity that causes oral candidiasis. It has been reported that cytochrome P450 enzyme (CYP51), a vital part of the ergosterol synthesis cascade, is associated with Candida infections and its biofilm formation. Thidiazuron, a phenyl-urea cytokinin, exhibits anti-senescence and elicitor activity against fungal infection in plants. However, how Thidiazuron impacts C. albicans biofilm formation is still uncertain. Here, we aimed to investigate the effects of a Thidiazuron against the growth and biofilm formation properties of C. albicans using in silico and in vitro experimental approaches. A preliminary molecular docking study revealed potential interaction between Thidiazuron and amino acid residues of CYP51. Further in vitro antifungal susceptibility test, scanning electron microscopy (SEM) and time kill analysis revealed the anti-fungal activity of Thidiazuron in both dose and time-dependent manner. Crystal violet staining, 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide (XTT) reduction assay revealed 50% inhibition in C. albicans biofilm by Thidiazuron at concentrations 11 and 19 µM respectively. Acridine orange staining assay visually confirmed the biofilm inhibitory potential of Thidiazuron. The gene expression study showed that Thidiazuron treatment down regulated the expression of genes involved in ergosterol synthesis (ERG3, ERG11, ERG25), cell adhesion (ASL3, EAP1), and hyphae development (EFG1, HWP1, SAP5) in C. albicans. Wherease, the expression of negative transcription regulator of hyphae (NRG1) was upregulated (5.7-fold) by Thidiazuron treatment. Collectively, our data suggest that Thidiazuron is a robust antifungal compound and an outstanding biofilm inhibitor, which may promise further therapeutic development due to CYP51 binding and inhibition of ergosterol formation against C. albicans.

Study on exogenous application of thidiazuron on seed size of Brassica napus L.

Thidiazuron (TDZ) is a novel and efficient cytokinin commonly used in tissue culture, and numerous studies have demonstrated that TDZ can increase berry size. However, no study to date has explored the effect of TDZ on seed size of Brassica napus and the mechanism. To shed light on the effect of TDZ on the seed size of B. napus, four different concentrations of TDZ were applied to B. napus. Results indicated that TDZ treatment could increase the seed diameter and silique length of B. napus to varying degrees and 100 and 200 µmol/L TDZ treatments were the most effective with a 3.6 and 4.6% increase in seed diameter, respectively. In addition, the yield of B. napus was also substantially increased under TDZ treatment. On the other hand, confocal micrographs of embryos and cotyledon cells suggested that embryos and their cotyledon epidermal cells treated with 200 µmol/L TDZ were obviously larger in size than the control. Furthermore, TDZ promoted the upregulation of some key maternal tissue growth-related genes, including two G-protein signaling genes (AGG3 and RGA1) and two transcriptional regulators (ANT and GS2). The expression analysis of genes related to the auxin metabolic pathways, G-protein signaling, endosperm growth and transcriptional regulators confirmed that treatment with TDZ negatively regulated the key genes ABI5, AGB1, AP2, ARF2, and ARF18 during bud development stage and florescence. The results strongly suggested that TDZ might regulate the transcriptional levels of key genes involved in auxin metabolic pathways, G-protein signaling, endosperm growth and transcriptional regulators, which resulted in bigger cotyledon epidermal cells and seed size in B. napus. This study explored the mechanism of TDZ treatment on the seed size of B. napus and provided an important reference for improving rapeseed yield.

Thidiazuron Promotes Leaf Abscission by Regulating the Crosstalk Complexities between Ethylene, Auxin, and Cytokinin in Cotton.

Thidiazuron (TDZ) is widely used as a defoliant to induce leaf abscission in cotton. However, the underlying molecular mechanism is still unclear. In this study, RNA-seq and enzyme-linked immunosorbent assays (ELISA) were performed to reveal the dynamic transcriptome profiling and the change of endogenous phytohormones upon TDZ treatment in leaf, petiole, and abscission zone (AZ). We found that TDZ induced the gene expression of ethylene biosynthesis and signal, and promoted ethylene accumulation earlier in leaf than that in AZ. While TDZ down-regulated indole-3-acetic acid (IAA) biosynthesis genes mainly in leaf and IAA signal and transport genes. Furthermore, the IAA content reduced more sharply in the leaf than that in AZ to change the auxin gradient for abscission. TDZ suppressed CTK biosynthesis genes and induced CTK metabolic genes to reduce the IPA accumulation for the reduction of ethylene sensitivity. Furthermore, TDZ regulated the gene expression of abscisic acid (ABA) biosynthesis and signal and induced ABA accumulation between 12-48 h, which could up-regulate ABA response factor genes and inhibit IAA transporter genes. Our data suggest that TDZ orchestrates metabolism and signal of ethylene, auxin, and cytokinin, and also the transport of auxin in leaf, petiole, and AZ, to control leaf abscission.

The multipotent thidiazuron: A mechanistic overview of its roles in callogenesis and other plant cultures in vitro.

Thidiazuron (TDZ) is an active substituted phenyl urea compound that has found a significant role as a plant growth regulator. The most exciting aspect of its function is that it can mimic auxins and cytokinin but is chemically different from these two. Many theories have been put forward, and experiments performed to understand the mode of action of TDZ in callogenesis. One suggested mechanism presents that it works by inhibiting the cytokinin degrading enzymes that compete with cytokinin for an active site on the enzyme. An example is the TDZ-induced suppressed expression of gibberellic acid (GA) biosynthesis genes encoding GA3 and GA20 oxidases. This is entailed with a slightly increased expression of GA catabolism genes encoding GA20 oxidase. Similarly, one of the recommendations is that TDZ induces the expression of specific genes and transcription regulatory sequences that are either responsible directly for callus formation or in turn induce other auxins or cytokinin for callogenesis. There is no concise review available that discusses the details of TDZ-induced callus, specifically and other in vitro cultures in general. This review is an attempt to explore all these pathways and mechanisms involved in callogenesis in plants stimulated by TDZ.

Auxin and cytokinin synergism in micropropagation for mass production of Aloe vera.

Aloe vera [Aloe vera (L.) Burm. f.] is considered a valuable medicinal plant worldwide due to its remarkable beneficial effects on human health. However, challenges in A. vera propagation hinder meeting the increasing demand in the health and beauty sectors. As an alternative method, in vitro propagation is crucial for the mass production of Aloe plants, which is a rapid method as well. Therefore, the present study aimed to establish an efficient micropropagation protocol for A. vera by in vitro optimization of the effect of different plant growth regulators (PGRs). For shoot proliferation, sterilized explants were inoculated on the Murashige and Skoog (MS) medium supplemented with 6-benzylaminopurine (BAP) and thidiazuron (0.5, 1.0, 2.0, and 4.0 mg/l) in combination with 0.5 mg/l naphthaleneacetic acid (NAA). Subsequently, indole-3-butyric acid (IBA) (1.0, 2.0, and 3.0 mg/l) was used for root induction. It was found that the explants cultured on the MS medium supplemented with 4.0 mg/l BAP + 0.5 mg/l NAA showed the highest percentage of response (90 ± 1.29) for shoot induction within the minimum number of days (5 ± 0.33). The highest number of shoots (2.7 ± 0.36) and length of shoots (4.7 ± 0.42 cm) per explant were also observed with the same concentration of PGRs. However, the highest number of roots (3.2 ± 0.57), length of roots (5.67 ± 0.21 cm), and root induction (80 ± 1.97 %) were noticed within the minimum number of days (11 ± 0.79) on the MS medium supplemented with 1.0 mg/l IBA. Thus, the proposed method is a quick and effective approach for the mass propagation of A. vera with appropriate dosages of auxins and cytokinins, which may allow meeting the increasing commercial demand.

High-frequency adventitious shoot organogenesis from in vitro stem explants of Scutellaria araxensis Grossh.

The present study introduced an in vitro shoot organogenesis protocol for the medicinal plant Scutellaria araxensis (Lamiaceae). Stem, leaf, and petiole explants were cultured in half-strength Murashige and Skoog (MS) medium containing different concentrations of 6-benzylaminopurine (BAP) alone or in combination with thidiazuron (TDZ), indole-3-butyric acid (IBA), or α-naphthalene acetic acid. Callus formation occurred from stem and petiole explants in most cultures; however, in leaf explants, it was observed only in cultures containing 0.5 mg/l BAP supplemented with TDZ at all concentrations. The highest frequency of indirect shoot induction (100 and 90%) with an average of 20.33 and 12 shoots per explant was observed in stem-derived calli cultured on half-strength MS medium containing 2.0 mg/l BAP plus 0.5 and 1.5 mg/l TDZ, respectively. The best direct shoot organogenesis (40%) was observed in stem explants cultured on half-strength MS medium containing 0.5 mg/l BAP and 0.5 mg/l IBA with a mean of 18 shoots per stem explant. The regenerated micro-shoots were elongated on a medium fortified with 0.5 mg/l gibberellic acid and then successfully rooted in half-strength MS medium supplemented with 0.5 mg/l IBA. The obtained plantlets were acclimatized in a growth chamber with a survival rate of 100%. This study is the first report of a simple and efficient in vitro shoot organogenesis and regeneration protocol for S. araxensis by using stem explants, which could be useful for the conservation, genetic manipulation, and exploitation of biological molecules of this valuable genetic source.

Plant Growth Regulators INCYDE and TD-K Underperform in Cereal Field Trials.

Using plant growth regulators to alter cytokinin homeostasis with the aim of enhancing endogenous cytokinin levels has been proposed as a strategy to increase yields in wheat and barley. The plant growth regulators INCYDE and CPPU inhibit the cytokinin degrading enzyme cytokinin oxidase/dehydrogenase (CKX), while TD-K inhibits the process of senescence. We report that the application of these plant growth regulators in wheat and barley field trials failed to enhance yields, or change the components of yields. Analyses of the endogenous cytokinin content showed a high concentration of trans-zeatin (tZ) in both wheat and barley grains at four days after anthesis, and statistically significant, but probably biologically insignificant, increases in cisZ-O-glucoside, along with small decreases in cZ riboside (cZR), dihydro Z (DHZ), and DHZR and DHZOG cytokinins, following INCYDE application to barley at anthesis. We discuss possible reasons for the lack of efficacy of the three plant growth regulators under field conditions and comment on future approaches to manipulating yield in the light of the strong homeostatic mechanisms controlling endogenous cytokinin levels.

[Determination of plant growth regulators in animal-derived foods using QuEChERS-isotope-labeled internal standards with high performance liquid chromatography-tandem mass spectrometry].

As among the most widely used pesticides in agriculture, plant growth regulators (PGRs) have a positive influence on plants. However, the overuse of PGRs may induce toxicity in food and even be hazardous to human health. Numerous studies have investigated the presence and residues of PGRs on vegetables and fruits. Animal-derived foods are one of the most dominant food sources providing nutrients to fulfil the daily dietary intake, and could also be potentially contaminated by PGRs. However, there is little information on PGR residues in animal-derived foods. Standardization also lacks among the techniques for PGR determination in animal-derived foods, thereby restricting the further establishment of pesticide usage and food safety regulations. Therefore, in this study, a rapid and effective method for analyzing chlormequat chloride, thidiazuron, and paclobutrazol in animal-derived food samples was established. The method primarily involves high performance liquid chromatography-tandem mass spectrometry combined with the use of isotope-labeled internal standards. The extraction and clean-up procedures were based on the QuEChERS method. The analytes were extracted from pork, beef, chicken, pork liver, egg, and milk samples using acetonitrile, followed by 4 g anhydrous magnesium sulfate (MgSO4), and 1 g sodium chloride (NaCl). The supernatant was removed using a mixture of 50 mg N-propyl ethylenediamine (PSA), 50 mg octadecyl silane (C18), and 150 mg MgSO4, and then passed through a 0.22 µm membrane filter before determination. The Agilent ZORBAX Eclipse Plus C18 column (150 mm×3.0 mm, 1.8 µm) was used to separate the analytes under a gradient elution program, with acetonitrile and 5 mmol/L ammonium acetate solution as mobile phases. The analytes were detected by mass spectrometry using the positive and negative electrospray ionization modes under the multiple reaction monitoring mode. Matrix-matched calibration combined with internal standards was used to quantify the PGRs. The linear regression correlation coefficients (r2) for the PGRs were all greater than 0.990 in the corresponding linear concentration ranges. Chlormequat chloride, thidiazuron, and paclobutrazol showed good linearities in the range of 0.1-100 µg/L for the egg and pork liver samples and 0.1-50 µg/L for the pork, beef, and chicken samples. For the milk samples, thidiazuron and paclobutrazol showed good linearities in the range of 0.05-10 µg/L, while chlormequat chloride showed linearity in the range of 0.05-5 µg/L. The limit of detection (LOD) and limit of quantification (LOQ) for each PGR were based on the signal-to-noise (S/N) ratios. Under optimal conditions, the LODs ranged from 0.01 µg/kg to 0.1 µg/kg, where the LOD was defined as the amount of the tested compound that generated an S/N ratio higher than 3. In addition, the LOQs were in the range of 0.5-5 µg/kg, with an S/N ratio higher than 10. The precision and accuracy were evaluated by recovery experiments. At the LOQ, twice the LOQ, and 10 times the LOQ, the mean recoveries were in the range of 70.0%-117.4%, and the relative standard deviations (RSDs) ranged from 0.8% to 16.1%. The results indicated that the proposed method is accurate and reliable. This method is a modification of the QuEChERS method, and is advantageous owing to its simplicity and high sensitivity. The use of matrix-matching calibration curves and internal standards can eliminate matrix interference, thereby increasing the accuracy of the method. This method satisfies the testing requirements for chlormequat chloride, thidiazuron, and paclobutrazol residues in animal-derived foods, and is promising for the determination of other PGRs or other types of pesticides in animal-derived foods.

A Cytokinin Analog Thidiazuron Suppresses Shoot Growth in Potted Rose Plants via the Gibberellic Acid Pathway.

Application of thidiazuron (N-phenyl-N'-1,2,3-thiadiazol-5-ylurea, TDZ), a cytokinin analog, to inhibit the leaf yellowing that occurs after pinching potted rose plants, resulted in compact plants with shorter shoots and thicker internodes. Two weeks after treatment with 100 µM of TDZ, new shoots were half as long as those in control plants, and stem diameters were about 40% greater. This effect of TDZ is associated with changes in cell architecture. Although TDZ treatment stimulated ethylene production by the plants, inhibitors of ethylene biosynthesis (2-aminoethoxyvinyl glycine) or action (silver thiosulfate) did not affect the response of plants to TDZ. We found that TDZ treatment significantly suppressed the expression of bioactive gibberellic acid (GA) biosynthesis genes encoding GA3 and GA20 oxidases and slightly increased the expression of GA catabolism genes encoding GA2 oxidase. Application of GA3 and TDZ together resulted in normal elongation growth, although stem diameters were still somewhat thicker. Our results suggest that TDZ regulates shoot elongation and stem enlargement in potted rose plants through the modulation of bioactive GA biosynthesis.

Influence of different types of explants in chickpea regeneration using thidiazuron seed-priming.

A comparative regeneration of three types of explants prepared from axillary meristems, plumular apices and hypocotyls of chickpea (Cicer arietinum) was carried out using four thidiazuron (TDZ) treatment methods. The first and third ones included the short-term 20 µM TDZ pre-treatment for all three explant types followed by non-supplementation or supplementation of TDZ (4 µM) into the shoot induction medium (SIM), while the second and fourth ones lacked TDZ pre-treatment followed by non-addition or addition of 4 µM TDZ in the SIM. Axillary meristem explants produced the best results with seed pre-treatment using 20 µM TDZ without TDZ in SIM and showed the highest rate of regeneration efficiency (71.33 ± 1.5%) after 20 days. Concurrently, plumular apex explants from TDZ-primed seeds was ranked second, exhibiting a regeneration percentage of 54.33 ± 2.3% in SIM without supplementation of TDZ, whereas explants from hypocotyls generated from seeds subjected to any of the TDZ treatments were not regenerated on any SIMs after 20 days.

Effects of different pesticides treatments on the nutritional quality of kiwifruit.

Pesticides are widely used in the process of kiwifruit growth to promote fruit expansion. This study was aimed to assess the effects of pesticides on the quality of kiwifruit by applying high and normal concentrations of forchlorfenuron (CPPU) and thidiazuron (TDZ) to "Xuxiang" (XX) green kiwifruit and "Jinyan" (JY) gold kiwifruit. Sixty kiwifruit trees were used to comprehensively evaluate the effects on the pulp and whole kiwifruit. In addition to the weight gain effect and basic physical-chemical properties (vitamin C, total protein, glucose and fructose, organic acids), the main nutritional qualities (in vitro and cellular antioxidant activity (CAA), and dietary minerals) were also evaluated. The vitamin C content of XX was not affected by pesticides, but the use of CPPU reduced vitamin C of JY pulp by 23% (p < 0.05). Pesticides did not reduce the antioxidant values of XX pulp in vitro but significantly reduced CAA values (32%-47%). In JY pulp, pesticides treatments had no significant effect on antioxidant values in vitro except that CPPU treatments significantly reduced the ferric reducing antioxidant power (FRAP) value by 21% (p < 0.05). Reasonable use of pesticides can effectively improve taste of kiwifruit, increasing kiwifruit weight and the content of certain nutrients. PRACTICAL APPLICATION: Based on observed changes in nutritional components, CPPU may be more suitable for XX while TDZ may be more suitable for JY. The significance of this study may affect kiwifruit farmers and ultimately help improve the sensory quality of kiwifruit.

Thidiazuron-induced direct organogenesis from immature inflorescence of three date palm cultivars.

BACKGROUND: Inflorescence explants of date palm proved to be a promising tool for micropropagation of elite cultivars or rare males and females as organogenesis and somatic embryogenesis could be achieved. These plant materials are abundantly available every year and can be used as cheap and potent explants. Nevertheless, many difficulties could be faced in this protocol according to selection of the spathe size and age, media components, growth regulators, etc. The aim of this study was to determine the influence of various cytokinins on direct organs induction of three date palm cultivars (Selmi, Barhee, and Medjool) from immature inflorescence. An additional objective of this study was to investigate the effect of cytokinins and auxins on growth and development of Medjool cultivar. RESULTS: Various combinations of cytokinins were investigated on three date palm inflorescences as N6-(2-isopentenyl) adenine (2iP), kinetin, benzyleadenine (BA), and thidiazuron (N-phenyl-N'-1,2,3-thidiazol-5-yl urea) (TDZ). TDZ alone or in combination with BA proved to be superior for direct organogenesis in all three cultivars so that another combination of TDZ with BA was conducted. Results showed that moderate concentration of BA, with TDZ, gave superior response. Medjool cultivar response surpassed other two cultivars that made the possibility to conduct some growth regulators treatments on its multiplication and regeneration. TDZ at 0.5 + BA at 1.0 mg/l without activated charcoal seemed to enhance multiplication rate. Medium containing 0.5 mg/l of both naphthaleneacetic acid and indole butyric acid in addition to 1.0 mg/l indole acetic acid appeared to be more suitable for rooting stage of Medjool shootlets. CONCLUSION: In this study, we created an innovation sequence of growth regulators included in nutrient media for date palm direct organogenesis from inflorescence. Organogenesis has been accelerated from immature inflorescence explants and developed to healthy plantlets which acclimatized in greenhouse.

Effects of different hormonal treatments on growth parameters and secondary metabolite production in organ culture of Hyssopus officinalis L.

Hyssopus officinalis L. is a medicinal plant containing valuable phytochemicals and is used extensively in the pharmaceutical industry. As this plant naturally contains low levels of these metabolites, plant cell and tissue culture technologies are used to produce them in large volumes. The present study aimed first to evaluate the effects of different types of cytokinins, including benzyl adenine (BA), kinetin (KIN), and thidiazuron (TDZ), at 1 ppm concentration in the culture medium on growth parameters and production of secondary metabolites and photosynthetic pigments in organ culture of H. officinalis; in the second step, the study investigated the effect of different concentrations (0, 0.2, 1, 1.5, and 2 ppm) of the most effective type of cytokinin. The results showed that TDZ was the optimal type of growth regulator compared to BA and KIN as it showed a positive influence on the studied traits; furthermore, its highest concentration of 2 ppm in culture medium was determined to be the best one that enabled the highest production of secondary metabolites and photosynthetic pigments. We conclude that the presence of growth regulators can strongly influence the growth and development of plants in tissue culture conditions.

Thidiazuron suppresses breast cancer via targeting miR-132 and dysregulation of the PI3K-Akt signaling pathway mediated by the miR-202-5p-PTEN axis.

Chemo-resistance and metastasis are the most common causes of breast cancer recurrence and death. Thidiazuron (TDZ) is a plant growth regulator (phytohormone) whose biological effects on humans and animals has not yet been determined. In this study, we investigated the anticancer activity of this phytohormone on the drug resistant-triple negative breast cancer cell line MDA-MB-231. Treatment of the breast cancer cells with TDZ (1-50 µmol/L) caused more stressful environment and induced a significant increase in active caspase-positive cells. In addition, TDZ treatment (5 and 10 µmol/L) significantly attenuated the migration and the invasiveness of these highly metastatic cancer cells. Mechanistically, TDZ reduces cancer progression and invasiveness by targeting miR-202-5p, which stimulates the expression of phosphatase and tensin homolog (PTEN), the tumor suppressor that downregulates the PI3K-Akt signaling pathway. Treatment with TDZ significantly upregulates miRNA-132, the suppressor of breast cancer proliferation, which is also implicated in dysregulation of the TEN-Akt-NFκB signaling pathway. Interestingly, our molecular docking analysis revealed a potential non-covalent interaction between TDZ and Akt, PTEN, and PI3K. These findings suggest that TDZ suppresses breast cancer metastasis by targeting miRNA-132, the miR-202-5p-PTEN axis, and the PI3K-Akt signaling pathway downstream.

Evaluation of Cotton (Gossypium hirsutum L.) Leaf Abscission Sensitivity Triggered by Thidiazuron through Membership Function Value.

Chemical defoliation is an essential agricultural practice in cotton production for mechanic harvesting. Thidiazuron (TDZ) is the active ingredient of the chemical defoliant used on cotton. So far, few studies havefocused on the method of identifying the sensitivity of cotton cultivars to TDZ. Therefore, a greenhouse soil culture experiment was performed by using two widely cultivatedupland cotton cultivars CRI 49 and CRI 12 treated with seven different concentrations (0, 100, 200, 300, 400, 500, and 1000 mg L-1) of TDZ at the seedling stage to establish a screening system. Principal component analysis and the membership function value (MFV) method was used to analyze the physiological and phenotypic characters, including abscission rate, amino acids content, net photosynthetic rate (Pn), etc. Finally, we developed a mathematical evaluation model, selected 100 mg L-1 TDZ as the optimal concentration and identified reliable characters net photosynthetic rate (Pn), stomatal conductance (Gs), and transpiration rate (Tr) to evaluate cotton leaf abscission sensitivity. These results also confirmed that CRI 12 was more sensitive to TDZ than CRI 49. This is the first time using a mathematical evaluation method to evaluate the cotton leaf abscission sensitivity triggered by TDZ at the seedling stage and the results were also confirmed in the field experiment. Furthermore, it will be valuable that MFV method is applied to stress sensitivity evaluation in other crop species under stress environment.