Indole-3-butyric Acid Research Articles

Tissue Culture Response and In Vitro Plant Regeneration of Malus 'Baiyun' (a New Cultivar of Ornamental Crabapple).

Malus 'Baiyun' (registration no. 20210210), a new crabapple cultivar, was registered in 2021 by the Nanjing Forestry Unversity. However, the difficult rooting has greatly limited the production of high-quality M. 'Baiyun' in industrialization development. There is thus a pressing need to develop an organogenesis protocol for the in vitro propagation of M. 'Baiyun' to alleviate a shortage of high-quality M. 'Baiyun' seedlings. The results showed that choosing the apical bud in mid-March was an excellent explant material. To promote proliferation, the highest proliferation (6.27) of apical shoots was cultured on Murashige and Skoog (MS) medium supplemented with 0.5 mg·L-1 6-benzylaminopurine(6-BA) + 0.05 mg·L-1 indole-3-butyric acid (IBA). Subsequently, a 100% rooting rate, average number of roots per shoot of 6.2 and maximum length of roots of 4.96 cm were obtained on half-strength Murashige and Skoog (1/2 MS) medium with the application of 0.5 mg·L-1 naphthaleneacetic acid (NAA) or 0.6 mg·L-1 NAA + 0.7 mg·L-1 IBA. Additionally, thick and lateral roots were obtained with 0.6 mg·L-1 NAA + 0.7 mg·L-1 IBA. Our study is the first to establish an effective organogenesis protocol for new crabapple cultivars using stem segments.

Factors governing cellular reprogramming competence in Arabidopsis adventitious root formation

Developmental reprogramming allows for flexibility in growth and adaptation to changing environmental conditions. In plants, wounding events can result in new stem cell niches and lateral organs. Adventitious roots develop from aerial parts of the plant and are regulated by multiple stimuli, including wounding. Here, we find that Arabidopsis thaliana seedlings wounded at the hypocotyl-root junction reprogram certain pericycle cells to produce adventitious roots proximal to the wound site. We have determined that competence for this reprogramming is controlled; basal cells close to the wound site can produce adventitious roots, whereas cells distal from the wound site mostly cannot. We found that altering cytokinin response or indole-3-butyric acid (IBA)-to-(indole-3-acetic acid) IAA conversion resulted in an expanded adventitious root competence zone and delineated the connection between these pathways. Our work highlights the importance of endogenous IBA-derived auxin and its interaction with cytokinin in adventitious root formation and the regenerative properties of plants.

The Leafy-Stem-Buried Etiolation Contributed to the High Efficiency of Rootstock Vegetative Propagation in Avocado (Persea americana)

Because of their tolerance to root rot and many abiotic stresses, rootstocks are generally required for commercial avocado production. However, cutting and air-layering, which are popular methods of vegetative propagation for producing large numbers of uniform and genetically identical plants, have been unsuccessful for years. To develop a practical and efficient rooting procedure for selected avocado clonal rootstocks, the present research investigated the effects of various factors on rooting cutting. Shoots were divided into three groups (air layering, direct cutting, and stem-buried etiolation) and treated with different combinations (plant growth regulators, PGRs; soaking time; and culture media), in which orthogonal or randomized-block designs were used. The rooting rate, average root length, average root number, average root dry weight, and rooting quality (Q value) were used as evaluation indicators. The results show that etiolation treatment of the mother shoot is the requisite condition for avocado shoot rooting. In addition, the rooting effect of etiolated cuttings was strongly impacted by PGR type, concentration, and soaking time, whereas no significant differences were detected among the culture media. Among these factors, the roots and the survival rates of etiolated cuttings of two hard-to-root varieties were optimal under the following conditions: indolebutyric acid concentration of 2500 mg/L, dipping duration for 5 s, and perlite:vermiculite culture at 1:1. The rooting rate of ‘Dusa’ was generally greater than that of ‘Duke 7’ and reached 82%.

Impact of Various IBA Concentrations on Rooting in Apical Shoot Cutting and Stem Cuttings of Callistemon lanceolatus (Sm.) Sweet in Polytunnel Conditions

The study was undertaken to identify the optimal concentration of IBA and type of cuttings suitable for propagation of Callistemon lanceolatus and it was conducted at the Vanavarayar Institute of Agriculture, Pollachi, Coimbatore, India from December 2022 to September 2023. The experiment addressed the challenges of seed propagation, such as their seed capsules need to be activated by fire and the unpredictable nature of seed germination, which results in high progeny diversity due to genetic recombination. The investigation focused on apical and stem cuttings subjected to fifteen different treatments with three replications each; the Tukey test was used for statistical analysis; the cuttings were treated with various concentrations of Indole-3-butyric acid (IBA) and placed under polytunnel conditions; observations were made after 45 days, measuring sprouting percentage, rooting percentage, mean number of leaves, shoot length, mean number of roots, and root length per cutting. In light of these issues, the study explored clonal propagation as an alternative for mass multiplication of elite trees. The results of the study depicted that the maximum rooting percentage and root length were observed in T6 (73.28±8.87%) and (12.54±0.00cm) due to the exogenous application of auxin. On the whole, the result of this investigation suggest that apical shoot cuttings with IBA at 6000ppm can be made to induce maximum rooting and to produce high quality planting stock material for clonal propagation in Callistemon lanceolatus.

Tissue-Specific Natural Synthesis of Galanthaminein Zephyranthes Species and Its Accumulation in Different In Vitro-Grown Organs Following Methyl Jasmonate Treatment.

Galanthamine is an immensely valuable alkaloid exhibiting anti-cancer and antiviral activity. The cultivation of plant tissues in in vitro conditions is a good source for the synthesis and enrichment of secondary metabolites of commercial interest. In this study, the Amaryllidaceae alkaloid galanthamine was quantified in three Zephyranthes species, such as Zephyranthes candida, Zephyranthes grandiflora, and Zephyranthes citrina, and the impact of the methyl jasmonate (MJ) signaling molecule on galanthamine accumulation was monitored in in vitro-derived plant tissues. This is the first ever study of the MJ-regulated accumulation of galanthamine in in vitro-grown Zephyranthes tissues. Shoot regeneration was obtained in all three Zephyranthes species on Murashige and Skoog (MS) medium containing 2.0 mgL-1 benzylaminopurine (BAP) + 0.5 mgL-1 naphthalene acetic acid (NAA). The regenerated shoots were rooted on a medium containing 2.0 mgL-1 indole butyric acid (IBA). A GC-MS study of Zephyranthes extracts revealed the presence of 34 phyto-compounds of varied levels with therapeutic activities against diseases. The galanthamine content was quantified in plant parts of the three Zephyranthes species using high-performance thin layer chromatography (HPTLC); the maximum was found in Z. candida bulb (2.41 µg g-1 dry wt.), followed by Z. grandiflora (2.13 µg g-1 dry wt.), and then Z. citrina (2.02 µg g-1 dry wt.). The galanthamine content showed bulb > leaf > root source order. The in vitro-generated plantlets were treated with different MJ concentrations, and the galanthamine yield was measured in bulb, leaf, and root tissues. The highest galanthamine content was recorded in bulbs of Z. candida (3.97 µg g-1 dry wt.) treated with 150 µM MJ, showing an increase of 64.73% compared to the control. This accumulation may be attributed to MJ-induced stress, highlighting the potential commercial synthesis of galanthamine in vitro.

Vegetative propagation of Bagoadlau (Xanthosthemon philippinensis Merr.) using indolebutyric acid

The research investigated the vegetative propagation of Bagoadlau (Xanthosthemon philippinensis Merr.) stem cuttings using different concentrations of indolebutyric acid (IBA). Pretreated cuttings were planted in polyethylene bags and observed in a fully covered chamber for 45 days. The study employed a single trial of completely randomized design (CRD) with five treatments (500 ppm, 100 ppm, 1,500 ppm, and 2000 ppm), each replicated four times. Results indicated significant variations among treatment means in terms of percent shooting, shoot length, percent rooting, number and length of adventitious roots, and percent callusing. Notably, 500 ppm and 1,500 ppm demonstrated the highest outcomes in percent shooting, shoot length, percent survival, measurement of adventitious roots, count of roots, and percentage of rooting. In contrast, the survival percentage of T2 (500 ppm) displayed the highest rate and consistent performance compared to other treatments. Hence, the study recommends using 500 ppm and 1,500 ppm for effective rooting of Bagoadlau (Xanthosthemon philippinensis Merr.) stem cuttings. The successful propagation of native species like Bagoadlau is particularly relevant to ecosystem restoration efforts in regions marked by land degradation and mining activities. The study addresses several crucial aspects by successfully establishing Bagoadlau on such lands. This includes the restoration of native biodiversity, improved soil, and water quality through stabilizing soil, preventing erosion, and acting as a natural filtration system.

Effect of Plant Growth Regulators on Mass Propagation of Strawberry (Fragaria sp.)

Efficient in vitro regeneration protocols for strawberries are crucial for accelerating the propagation of superior cultivars and improving overall productivity through controlled manipulation of plant growth regulators. This study investigated the influence of different concentrations and combinations of plant growth regulators on in vitro regeneration process of strawberries. BARI Strawberry-1 runner tips were sterilized and placed on Murashige and Skoog medium (MS) supplemented with various combinations of cytokinins, including 6-benzylaminopurine (BAP) and kinetin (KIN), to initiate shoot growth. Notably, the combination of 1.5 mg/L BAP + 1.0 mg/L KIN led to the shortest duration for shoot initiation (9 days), resulting in the highest number of shoots per explants (6.33), longest shoot length (2.87 cm), and maximum number of leaves per shoot (4.00). Additionally, this combination also exhibited the highest rate of shoot regeneration (70.33%). Subsequently, the proliferated shoots were transferred to MS medium supplemented with various concentrations and combinations of auxins, specifically 3-indolebutyric acid (IBA) and 1-naphthaleneacetic acid (NAA), for root induction. The in vitro regenerated shoots cultured in MS medium supplemented with 1.5 mg/L IBA + 1.0 mg/L NAA showed the shortest duration for root formation (8 days), the highest number of roots per explants (4.00), and the longest root length (2.77 cm). Furthermore, this combination also resulted in the highest rate of root regeneration (40%). These findings contribute valuable insights for the mass production of healthy strawberry plantlets using in vitro culture techniques. J Bangladesh Agril Univ 22(2):178-184, 2024

Anti-oomycete activity and plant growth promoting properties of avocado fungal endophytes

Fungal endophytes are known as promising plant growth-promoting microorganisms. Surprisingly, despite the economic importance of avocado, the antimicrobial and plant growth-promoting properties of its fungal endophytes have seldom been investigated. Our objectives were to evaluate the anti-oomycete activity of avocado fungal endophytes and assess their potential plant growth-promoting properties, using Arabidopsis thaliana as a model plant. In total, 89 fungal isolates were obtained from the roots of avocado trees and grouped into 24 morphotypes. One isolate per morphotype was randomly selected to assess its antagonistic activity against Phytophthora cinnamomi through dual culture assays. The strongest inhibition of P. cinnamomi was induced by endophytic fungi belonging to the Fusarium, Mortierella and Penicillium genera. The six most promising fungal isolates were selected to assess their plant growth-promoting traits in co-inoculation assays with A. thaliana. All tested fungal endophytes were able to modify the plant root architecture and increase the number of lateral roots. Moreover, an accumulation of auxins was detected in the xylem and meristematic zone of plants inoculated with Mortierella sp. PC-T3-3.1 and Metapochonia sp. PC-T2-4.2, whilst auxin accumulation was restricted to the emerging lateral roots of plants inoculated with Penicillium sp. C-T0-3.1. Indole quantification showed that Penicillium sp. C-T0-3.1 produced the highest concentration of indole acetic acid (IAA) and indole butyric acid (IBA), despite the lack of auxin responsiveness in plants in the co-inoculation assays. Mortierella sp. PC-T3-3.1 and Metapochonia sp. PC-T2-4.2 produced more IAA and IBA when co-inoculated with A. thaliana than when growing alone, which suggests that sensing of plant signals could induce the production of auxin-like compounds by these two endophytes. Collectively, our findings contribute to elucidate the mechanisms underpinning the plant growth-promoting activity of avocado fungal endophytes, which will be key to harness their full metabolic potential.

Optimization of in vitro Regeneration of Cowpea (Vigna unguiculata L.) using Computational Models

Cowpea (Vigna unguiculata L.) is the most preferable cultivated crop in the World and can grow on poor soil with water scarcity. More than 80.0% of its cultivation is confined to the Sub-Saharan African continent. However, it is now one of the most preferable crops in Asia and Europe due to its low nutritional and water demand during cultivation under field conditions. In this study, the Bodrum Red cultivar of cowpea was used for in vitro regeneration. The 9-0 days old half cotyledonary node explant was used and placed on different concentrations of Benzylaminopurine (BAP), Indole-butyric acid (IBA), and Naphthalene acetic acid (NAA). The results were analyzed by ANOVA and response surface methodology (RSM). The ANOVA analysis revealed the maximum shoots from the medium enriched with 1.0 mg/L BAP with shot counts ranging from 1.17-3.11. The results were further analyzed by surface regression analysis which revealed the significant impact of NAA on callus formation. The results were also analyzed through Pareto charts and normal plots which confirmed the significant role of BAP and NAA on in vitro regeneration. The use of a response optimizer revealed the maximum shoot counts of 3.0 per explant from the medium supplemented with BAP. Results revealed the significance of RSM for optimizing input factors precisely for multiple input factors simultaneously. Advanced biotechnological approaches like genetic engineering and marker-assisted selection could enhance cowpea resilience to environmental conditions, ensuring its sustainability and adaptability across diverse agroecological zones with the aid of RSM

PIN2-mediated self-organizing transient auxin flow contributes to auxin maxima at the tip of Arabidopsis cotyledons.

Directional auxin transport and formation of auxin maxima are critical for embryogenesis, organogenesis, pattern formation, and growth coordination in plants, but the mechanisms underpinning the initiation and establishment of these auxin dynamics are not fully understood. Here we show that a self-initiating and -terminating transient auxin flow along the marginal cells (MCs) contributes to the formation of an auxin maximum at the tip of Arabidopsis cotyledon that globally coordinates the interdigitation of puzzle-shaped pavement cells in the cotyledon epidermis. Prior to the interdigitation, indole butyric acid (IBA) is converted to indole acetic acid (IAA) to induce PIN2 accumulation and polarization in the marginal cells, leading to auxin flow toward and accumulation at the cotyledon tip. When IAA levels at the cotyledon tip reaches a maximum, it activates pavement cell interdigitation as well as the accumulation of the IBA transporter TOB1 in MCs, which sequesters IBA to the vacuole and reduces IBA availability and IAA levels. The reduction of IAA levels results in PIN2 down-regulation and cessation of the auxin flow. Hence, our results elucidate a self-activating and self-terminating transient polar auxin transport system in cotyledons, contributing to the formation of localized auxin maxima that spatiotemporally coordinate pavement cell interdigitation.

In vitro morphogenesis and micro-morpho-anatomical developments in Moringa concanensis Nimmo.: An endemic tree of Indian sub-continent

Moringa concanensis Nimmo. is a regionally important and underutilized medicinal tree of the Indian subcontinent. An in vitro morphogenesis protocol for Moringa concanensis has been developed using seedling-derived explants. The cotyledonary node explants were found to be the most suitable exhibiting cent-percent bud break with each regenerating 2.33±0.76 shoots of 1.32±0.69 cm length within 15 days on 1.0 mg/L 6-benzyl aminopurine (BAP) supplemented modified Murashige and Skoog Medium (MMS) media. The rate of shoot multiplication increased up to 10.17±2.54 shoots/inoculum by sub-culturing of regenerated shoots on 0.5 mg/L BAP along with 0.1 mg/L Indole acetic acid (IAA). The in vitro cloned shoots were rooted using both in vitro and ex-vitro methods by applications of root-inducing auxins, indole butyric acid (IBA), and naphthalene acetic acid (NAA). IBA proved to be more effective and induced roots in all in vitro raised shoots. It produced 17.72±4.83 roots/shoot with 2.12±0.88 cm length on 1/4th strength MMS media fortified with 1.0 mg/L of IBA. Ex vitro rooted plantlets with concurrent acclimatization were achieved by pre-treating shoot bases with IBA at 250 ppm for 5 min. Comparative micro-morpho-anatomical evaluation of leaf and stem revealed differentiation of non-glandular trichomes, anomocytic stomata, and vascular tissue development under applied in vitro conditions, which suggests the survivability of plantlets. Sixty percent of the in vitro regenerated plants survived in the field. It is the foremost report on in vitro morphogenesis of Moringa concanensis protocol using cotyledonary nodal explant and ex vitro rooting method. The tissue culture methods defined and developed can be used for large-scale multiplications of Moringa concanensis as non-conventional approaches.

Effect of Plant Growth Regulators and Growing Media on Rooting of Cuttings in Punica granatum L. cv. Bhagwa

Background: When pomegranates are multiplied through seeds, germination leads to vigorous tree growth. However, the tree will not be exactly similar to its parent and the resultant fruit produced will be irregular in colour, size, juiciness and sweetness. Methods: Soft-wood cuttings of Pomegranate cv. Bhagwa were planted in different growing media that were entitled G1- Soil + FYM, G2- Soil + Vermiculite, G3- Soil + Sand + FYM and G4- Soil + FYM + Vermiculite. These cuttings were treated with different combinations of 1-Naphthaleneacetic acid (NAA), Indole-3-butyric acid (IBA), Hydrogen peroxide (H2O2), Ascorbic acid (ASC) and Boric acid. Studies were carried out in a two-factorial randomized block design (FRBD) with 28 treatment permutations. Result: Current research indicated that treatment T18 (NAA 500 ppm + H2O2 30 ppm + IBA 500 ppm, Soil + Vermiculite (1:1) worked out to be the best treatment as it exhibited superiority over other treatments. The results of this experiment can practically be implemented to propagate quality planting material by adopting these best results/treatments.

In Vitro Micropropagation of the Vulnerable Chilean Endemic Alstroemeria pelegrina L.

The Chilean rhizomatous geophyte Alstroemeria pelegrina (A. pelegrina), a species endemic to the Coquimbo (31°45′ S) and Valparaíso (33°12′ S) regions, is currently classified as vulnerable and experiencing population decline due to loss of habitat. This heightened threat underscores the need to develop effective mass propagation techniques to support its conservation efforts. Consequently, the present study aimed to establish an optimized in vitro propagation protocol tailored specifically for A. pelegrina to facilitate its large-scale propagation and promote the preservation of this vulnerable geophyte. In our experiment, explants obtained from in vitro germination were used. These explants were then cultured on a Murashige and Skoog (MS) medium solidified with agar (6 g L−1) and supplemented with 2.22 μM 6-Benzylaminopurine (BAP) and 30 g L−1 sucrose. The results indicated an average of 4.6 new shoots produced per initial explant. The implementation of light-emitting diode (LED) illumination with a red:blue ratio of 3:1 and 2.22 μM BAP resulted in an average shoot length of 6.2 cm. For rhizome induction, the addition of either 5.37 μM 1-naphthaleneacetic acid (NAA) or 5.37 μM indole-3-butyric acid (IBA) resulted in average rhizome lengths of 1.9 cm and 1.7 cm, respectively, with fresh weights of the vitroplants ranging from 2.9 g to 3.1 g, and rooting percentages between 100% and 96%, respectively. Notably, the survival rate of rooted plants obtained through in vitro propagation was 90% after a 4-week acclimatization period in a cold greenhouse, indicating the efficacy of the developed protocol for mass propagation and conservation efforts of this vulnerable geophyte species.

Indole Butyric Acid Alleviated Cadmium Toxicity in Lettuce by Increasing the Polysaccharide Contents and the Cadmium-Binding Capacity of Root Cell Walls

Indole Butyric Acid Alleviated Cadmium Toxicity in Lettuce by Increasing the Polysaccharide Contents and the Cadmium-Binding Capacity of Root Cell Walls

Establishment of an <i>In Vitro</i> Propagation, Transformation, and Gene Editing System in Tomato (<i>Solanum lycopersicum</i>)

Tomato (<em>Solanum lycopersicum</em>), a family of Solanaceae, is an annual crop grown in fields and greenhouses. Tomato is the fourth-largest agricultural crop in the world, with a market value of more than $50 billion. Numerous attempts were conducted on the tomato for further improvement via <em>in vitro</em> regeneration and transformation. This study aims to establish <em>in vitro</em> multiplication, transformation, and gene editing systems in tomatoes by using cotyledon explants. Cotyledon explants were placed on the MS medium supported with 6-benzyl adenine (BA) and kinetin (Kin) at four different concentrations for shoot induction. The shoot induction from cotyledon explants significantly increased, and the regeneration rate was 45% after using BA at 8.8 µM compared to Kin. For root induction, indole-3-butyric acid (IBA) at 4.8 µM concentration revealed the highest number of explants producing root (55%). Three <em>Agrobacterium tumefaciens</em> strains (EHA105, GV3101, and LBA4404) were used to establish and develop a tomato transformation method. Each <em>Agrobacterium</em> strain harbors the plasmid pCAMBIA2301, including the <em>nptII </em>marker. <em>Agrobacterium</em> strain LBA4404 showed the lowest number of dead explants, besides increasing the number of explant-produced shoots (30%) and the number of shoots per transformed explants compared to GV3101 and EHA105 strains. Our results revealed that the success of tomato transformation depends on selecting a suitable <em>A.</em> <em>tumefaciens</em> strain. Finally, the tomato gene editing system was successfully established by transferring the pCAMBIA1300-pCas9-sgRNA-U3 binary vector into the cotyledon using the selective <em>Agrobacterium</em> strain LBA4404, and the transformation effectivity was confirmed by PCR analysis.

Comparative study between Salkowski reagent and chromatographic method for auxins quantification from bacterial production.

The Salkowski reagent method is a colorimetric technique used to determine auxin production, specifically as indole-3-acetic acid (IAA). It was developed to determine indoles rapidly; however, it does not follow Beer's law at high concentrations of IAA. Thus, there could be an overestimation of IAA with the Salkowski technique due to the detection of other indole compounds. This study aims to compare the Salkowski colorimetric method versus a chromatographic method to evidence the imprecision or overestimation obtained when auxins, such as indole-acetic acid (IAA), are determined as traits from promoting growth plant bacteria (PGPB), using ten different strains from three different isolation sources. The analysis used the same bacterial culture to compare the Salkowski colorimetric and chromatographic results. Each bacterium was cultivated in the modified TSA without or with tryptophan for 96 h. The same supernatant culture was used in both methods: Salkowski reagent and ultra-performance liquid chromatography coupled with a Mass Spectrometer (LC-MS/MS). The first method indicated 5.4 to 27.4 mg L-1 without tryptophan in ten evaluated strains. When tryptophan was used as an inductor of auxin production, an increase was observed with an interval from 4.4 to 160 mg L-1. The principal auxin produced by all strains was IAA from that evaluated by the LC-MS/MS method, with significantly higher concentration with tryptophan addition than without. Strains belonging to the Kocuria genus were highlighted by high IAA production. The indole-3-propionic acid (IPA) was detected in all the bacterial cultures without tryptophan and only in K. turfanensis As05 with tryptophan, while it was not detected in other strains. In addition, indole-3-butyric acid (IBA) was detected at trace levels (13-16 µg L-1). The Salkowski reagent overestimates the IAA concentration with an interval of 41-1042 folds without tryptophan and 7-16330 folds with tryptophan as inductor. In future works, it will be necessary to determine IAA or other auxins using more suitable sensitive techniques and methodologies.

Meta-Topolin as an Effective Benzyladenine Derivative to Improve the Multiplication Rate and Quality of In Vitro Axillary Shoots of Húsvéti Rozmaring Apple Scion.

In vitro mass propagation of apple plants plays an important role in the rapid multiplication of genetically uniform, disease-free scions and rootstocks with desired traits. Successful micropropagation of apple using axillary shoot cultures is influenced by several factors, the most critical of which is the cytokinin included in the culture medium. The impact of medium composition from single added cytokinins on shoot proliferation of apple scion Húsvéti rozmaring cultured on agar-agar gelled Murashige and Skoog medium fortified with indole butyric acid and gibberellic acid was investigated. The optimum concentration for efficient shoot multiplication differs according to the type of cytokinin. The highest significant multiplication rate (5.40 shoots/explant) was achieved using 2.0 μM thidiazuron while the longest shoots (1.80 cm) were observed on the medium containing benzyladenine at a concentration of 2.0 μM. However, application of either thidiazuron or benzyladenine as cytokinin source in the medium resulted in shoots of low quality, such as stunted and thickened shoots with small leaves. In the case of benzyladenine riboside, the 8 μM concentration was the most effective in increasing the multiplication rate (4.76 shoots/explant) but caused thickened stem development with tiny leaves. In the present study, meta-topolin was shown to be the most effective cytokinin that could be applied to induce sufficient multiplication (3.28 shoots/explant) and high-quality shoots along with shoot lengths of 1.46 cm when it was applied at concentrations of 4 μM. However, kinetin was the least active cytokinin; it practically did not induce the development of new shoots. The superior cytokinin for in vitro axillary shoot development of apple scion Húsvéti rozmaring with high-quality shoots was the meta-topolin, but it may be different depending on the variety/genotype under study.

Foliar application of Boron, Calcium, and Indole-3-butyric acid on onion plants to improve seed production

Onion is the third most important cultivated vegetable crop around the world. Two types of varieties are cultivated: Open pollinated cultivars (OP) and first generation hybrids (F1). Little is known about the effects of foliar applications on onion seed production. This study was conducted to evaluate the enhancement of onion seed yield and seed quality through foliar applications of Boron (B), Calcium (Ca), and an auxin, indole-3-butyric acid (IBA). Male-sterile lines (MSL), and OP planted in pots and open field conditions were used over four seasons. The experiments were carried out with different levels of nutrients and IBA applied to the plants. Our results showed that foliar applications of nutrients and plant growth regulators were effective methods to improve onion seed yield and the number of seed per fruit, while seed quality parameters remained stable. The seed yield was enhanced by B by up to 83 %, but with an increasingly wide variability in comparison to the control. Indole-3-butyric acid improved yields when it was applied alone and mixed with B and Ca (40–45 % for OP and MSL, respectively) compared to the control. Therefore, foliar application of IBA, B and Ca could be effective in improving onion seed yields.

Assessment the efficiency of willow water extract (WWE), indole-3-butyric acid (IBA) and micronutrients on the propagation of Petunia x hybrida by stem cuttings.

Assessment the efficiency of willow water extract (WWE), indole-3-butyric acid (IBA) and micronutrients on the propagation of Petunia x hybrida by stem cuttings.

Evaluating gut microbiome as a biomarker of pathological complete response in patients with early locally advanced triple negative breast cancer (LA TNBC): A pilot study.

593 Background: It has previously been shown that microbial metabolic pathways are differentially activated in immunotherapy resistance, hence can serve as potential biomarker as well as target for therapeutic intervention. With the advent of Immune Checkpoint Blockers (ICB) in the neoadjuvant (NA) setting of locally advanced (LA) TNBC, we hypothesized that similar microbial metabolite mediated resistance may be at play. We are presenting data demonstrating differences in microbiome and metabolites in these patients. Methods: 28 patients who received NA pembrolizumab and chemotherapyfor LA TNBC were identified at Moffitt Cancer Center and Tampa General Hospital between February 2022 to October 2023. Blood and stool samples were collected at therapy initiation, at completion of neoadjuvant treatment and/or when the patients developed grade 3 or higher toxicity to therapy. We evaluated stool metagenomics and untargeted stool/plasma metabolomics as correlatives. Patient characteristics were as follows: 21 Caucasian, 3 African-American, 2 Hispanic, 2 unknown, median age 51 years, median body mass index (BMI) 28.5 kg/m2. 17 patients had stage II, while 11 patients had stage III TNBC. Results: Response was assessed in 27 patients, of which 11 had pCR (ypT0/is ypN0) while 16 had residual disease (RD). 1 patient progressed, while on NA therapy, while 8 patients developed grade 3-4 immune related adverse events leading to treatment discontinuation and death in one patient. We conducted shallow shotgun metagenomic sequencing and untargeted metabolomic profiling on pre and post treatment fecal and plasma samples respectively to identify gut microbial diversity, composition and differentially abundant metabolites associated with pCR.There wasno difference in alpha and beta diversity; however significant enrichment of microbiota with genus Akkermansia HR 0.04, p 0.03 was noted in those with pCR. We observed higher abundance of tryptophan metabolizing clostridium species HR 50541, p <0.001, along with differential activation of microbial tryptophan pathway in those with residual disease, specifically higher abundance of hydroxyindole acetic acid HR 1.54 P<0.005, indole propionic acid HR 1.75 p 0.05 and indole butyric acid HR 1.86 p 0.04. Conclusions: To our knowledge this is the first analysis of differences in the microbiome and microbial metabolism in patients with LA TNBC treated with NA ICB. Despite being a small study, it shows a more aggressive disease pattern with higher RD than noted in KEYNOTE 522 and shows significant concern for serious immune mediated adverse effects. This highlights the importance of biomarkers to stratify patients most likely to benefit from ICB. Enrichment of microbiota and immunosuppressive tryptophan metabolites were associated with pCR and should be validated in large studies as biomarker of response to NA ICB in TNBC.