Gibberellic Acid Research Articles

A LBD transcription factor from moso bamboo, PheLBD12, regulates plant height in transgenic rice.

The regulation mechanism of bamboo height growth has always been one of the hotspots in developmental biology. In the preliminary work of this project, the function of LBD transcription factor regulating height growth was firstly studied. Here, a gene PheLBD12 regulating height growth was screened. PheLBD12-overexpressing transgenic rice had shorter internodes, less bioactive gibberellic acid (GA3), and were more sensitive to GA3 than wild-type (WT) plants, which implied that PheLBD12 involve in gibberellin (GA) pathway. The transcript levels of OsGA2ox3, that encoding GAs deactivated enzyme, was significantly enhanced in PheLBD12-overexpressing transgenic rice. The transcript levels of OsAP2-39, that directly regulating the expression of EUI1 to reduce GA levels, was also significantly enhanced in PheLBD12-overexpressing transgenic rice. Expectedly, yeast one-hybrid assays, Dual-luciferase reporter assay and EMSAs suggested that PheLBD12 directly interacted with the promoter of OsGA2ox3 and OsAP2-39. Together, our results reveal that PheLBD12 regulates plant height growth by modulating GA catabolism. Through the research of this topic, it enriches the research content of LBD transcription factors and it will theoretically enrich the research content of height growth regulation.

Effect of D-mannitol and Gibberellic Acid on Physiological Parameters, Early Seedling Growth Characteristics, and Some of the Most Important Chemical Components of Barberry (Berberis vulgaris L.)

Background: One of the important medicinal plants and agricultural products in Asia, particularly in Iran, is barberry, and both salinity and drought can cause osmotic or ionic imbalance in plant cells. In order to study the impacts of D-Mannitol and gibberellic acid on seed germination, physiological parameters, early seedling growth characteristics, and some of the most important chemical ingredients of barberry, one experiment is designed. Methods: The experimental design was Completely Randomized Design (CRD) with three replicates, and drought stress was done by D-mannitol at various stress levels, namely, 0 MPa, 40 MPa, and 80 MPa, and the reaction of studied cultivar was assessed on the basis of experimental characteristics associated to germination and seedling growth, and Gibberellic acid treatments were 0 mgL-1, 300 mgL-1, 600 mgL-1, and 900 mgL-1. Results: The effects of D-mannitol were significant in germination percentage, germination rate, seedling vigor index, chlorophyll a, total chlorophyll, leaf dry weight and total sugar. Experimental treatments such as germination percentage, germination rate, and total chlorophyll were also influenced by the application of gibberellic acid. The interaction between D-mannitol and gibberellic acid had significant effect on peroxidase activity. The highest germination percentage, germination rate, seedling vigor index, catalase activity, peroxide activity, and Chlorophyll a were obtained for 0 MPa application of D-Mannitol, followed by usage of 40 MPa, and 80 Mpa, respectively. The maximum total chlorophyll, relative water content, and leaf dry weight were also related to control treatment (0 MPa D-Mannitol), while the higher values of proline content, carotenoids and total sugar were obtained for 80 MPa application of D-Mannitol. The maximum values of germination rate, germination percentage, seedling vigor index, peroxidase activity, and chlorophyll a were related to control treatment (0 mgL-1 gibberellic acid), and the highest CAT activity was related to the application of 300 mgL-1 gibberellic acid. The highest total chlorophyll content and relative water content were related to 0 mgL-1 gibberellic acid, while the maximum praline content and leaf dry weight were obtained for the application of 600 mgL-1 and 0 mgL-1 gibberellic acid. There was not any significant difference in carotenoids between gibberellic acid treatments, while the application of 900 mgL-1 gibberellic acid obtained the highest value of total sugar of barberry. Conclusion: Conclusively, on the basis of the results, the application of 80 MPa D-Mannitol and 600 mgL-1 could be recommended as they can increase the absorption of nutrients and water.

Exploring native arsenic (As)-resistant bacteria: unveiling multifaceted mechanisms for plant growth promotion under As stress.

This study explores the plant growth-promoting effect (PGPE) and potential mechanisms of the arsenic (As)-resistant bacterium Flavobacterium sp. A9 (A9 hereafter). The influences of A9 on the growth of Arabidopsis thaliana, lettuce, and Brassica napus under As(V) stress were investigated. Additionally, a metabolome analysis was conducted to unravel the underlying mechanisms that facilitate PGPE. Results revealed that A9 significantly enhanced the fresh weight of Arabidopsis seedlings by 62.6%-135.4% under As(V) stress. A9 significantly increased root length (19.4%), phosphorus (25.28%), chlorophyll content (59%), pod number (24.42%), and weight (18.88%), while decreasing As content (48.33%, P≤.05) and oxidative stress of Arabidopsis. It also significantly promoted the growth of lettuce and B. napus under As(V) stress. A9 demonstrated the capability to produce≥31 beneficial substances contributing to plant growth promotion (e.g. gibberellic acid), stress tolerance (e.g. thiamine), and reduced As accumulation (e.g. siderophores). A9 significantly promoted the plant growth under As stress and decreased As accumulation by decreasing oxidative stress and releasing beneficial compounds.

Enhanced phytoremediation of cadmium-contaminated soil using chelating agents and plant growth regulators: effect and mechanism.

The heavy metal cadmium (Cd) is a major threat to food safety and human health. Phytoremediation is the most widely used remediation technology, and how to improve the remediation efficiency of phytoremediation has become a key issue. In this study, we constructed an intensive phytoremediation technology for remediation of Cd-contaminated soil with biodegradable chelating agent and plant growth regulator combined with maize and investigated the mechanism of this technology. The results showed that the best remediation effect was achieved in the treatment with 10-6 mol l-1 gibberellic acid (GA3) and 6 mmol kg-1 aspartate diethoxysuccinic acid (AES) combined with maize. In this treatment, the total biomass and extraction efficiency of maize were 3.6 and 8.67 times higher than those of the control, respectively, and the antioxidant enzyme activities of maize were also increased. The soil was enriched with dominant bacterial genera that promote plant growth and metabolism and tolerance to heavy metal stress, which in turn promoted maize growth and Cd accumulation. Structural equation modelling results indicated a large effect of plant Cd concentration and plant antioxidant enzyme activity on plant Cd extraction. The enhanced phytoremediation technology showed good potential for safe use of Cd-contaminated soil.

The crosstalk interaction of ethylene, gibberellins, and arbuscular mycorrhiza improves growth in salinized tomato plants by modulating the hormonal balance

Ethylene (ET) and gibberellins (GAs) play key roles in controlling the biotic and abiotic interactions between plants and environment. To gain insights about the role of ET and GAs interactions in the mycorrization and response to salinity of tomato (Solanum lycopersicum L.) plants, the ET-insensitive (Never-ripe, Nr), and the ET-overproducer (Epinastic, Epi) mutants and their wild type cv. Micro-Tom (MT), were inoculated or not with the arbuscular mycorrhizal fungi (AMF) Rhizophagus irregularis and exposed to control (0 mM NaCl) and salinity (100 mM NaCl) conditions, with and without gibberellic acid (10−6 M GA3) application during four weeks. Exogenous GA3 enhanced plant growth irrespective of the genotype, AMF, and salinity conditions, while an additional effect on growth by AMF was only found in the ET-overproducer (Epi) mutant under control and salinity conditions. Epi almost doubled the AMF colonization level under both conditions but was the most affected by salinity and GA3 application compared to MT and Nr. In contrast, Nr registered the lowest AMF colonization level, but GA3 produced a positive effect, particularly under salinity, with the highest leaf growth recovery. Foliar GA3 application increased the endogenous concentration of GA1, GA3, and total GAs, more intensively in AMF-Epi plants, where induced levels of the ET-precursor ACC were also found. Interestingly, GA4 which is associated with AMF colonization, registered the strongest genotype x GA x AMF × salinity interactions. The different growth responses in relation to those interactions are discussed.

Zinc and Boron Foliar Application Effects on Primed Mung Bean (Vigna radiata L.) Growth and Productivity

Mung bean is recognized for its abundant high-quality protein content. For human consumption, it is a high-quality protein source and also serves various purposes crops, its arvested residue is used for green manuring and also used for fodder purposes. The research aimed to assess the impact of foliar micronutrient application on primed mung bean (Vigna radiata). The experimental procedures were executed in the sandy loam soil prevalent in the central plain region of Punjab. The investigation was conducted during the Zaid season 2022, focusing on the (SML-1827) mung bean variety. Specifically, the research assessed the impact of foliar micronutrient applications involving zinc and boron at 15 and 45 days after sowing (DAS) on primed mung bean growth characteristics. The experimental design employed a Randomized Block Design, incorporating 11 distinct treatment combinations, each replicated thrice. The investigation revealed that foliar micronutrient treatment on primed mung bean substantially influenced growth and yield parameters. Growth indicators for mung bean exhibited a positive trend when zinc and boron were jointly applied to primed seeds with gibberellic acid, followed by a decline in the control group, which experienced typical growth conditions devoid of growth regulators and micronutrients. Specifically, the highest recorded plant height was 70.1 cm in the T9 (GA(50 mg.L-1) + ZnSO4 (0.5%) + B (1%)) treatment, while the lowest height was 58 cm in the T0 (control) treatment. Similarly, the most significant fresh weight was observed in T9 (GA(50 mg.L-1) + ZnSO4 (0.5%)+ B (1%)) treatments at 136.8 g, with the lowest weight recorded in T0 (control) treatments at 86.6g. the most significant grain yield was achieved in T9 112 g.m-2, followed by T10 (SA(150 mg.L-1)+ ZnSO4 (0.5%)+B (1%)) at 105.7 g.m-2. This study suggests micronutrients and growth regulators can be sustainable agricultural inputs to enhance soil health and productivity.

Sulfuric acid as a germination stimulator in forage soybean seeds (Neonotonia wightii)

Forage soybean (Neonotonia wightii) is a legume frequently used as a cover crop in field crops. However, as a species of the Phaseoloideae subfamily, it is characterized by the physical latency of the seed, which makes it difficult to obtain a high, homogeneous, and rapid germination. The aim of the present study was to determine which method of scarification stimulates the germination process to a greater extent. The following immersion times were evaluated: 5 to 20 minutes in 98% sulfuric acid, 24 hours in 5.4% sodium hypochlorite, water, and gibberellic acid [100 ppm], 15 minutes of treatment with sandpaper and the combination of these last two. They were distributed in a completely randomized experimental design, where eight treatments and a control were evaluated, with three replicates each and 200 seeds as experimental units, subjected to controlled conditions (germination chambers at constant temperatures and a relative humidity of 27 °C and 70%, respectively) during the spring of 2022. The results were favorable, a high germination percentage was obtained from seeds subjected to a 20-minute immersion time in sulfuric acid (90% germination and an average of six germinated seeds per day) and this was significantly higher than the rest, making it an effective method to break the physical latency of the seeds, as it removes the impermeable cover allowing inhibition and consequently the activation of the seed’s metabolism.

Sexual and Asexual Propagation of Wild Lime (Zanthoxylum fagara L. Sarg.), a Native Florida Plant with Ornamental and Ecological Value

Abstract A series of four propagation studies were implemented to better understand the seed biology of wild lime (Zanthoxylum fagara L. Sarg. [Rutaceae]) and its adventitious rooting response to auxin treatments. Plant origin (north central vs south Florida ecotypes) did not affect initial seed viability but significantly influenced germination response to seasonal temperatures. Fifty-five days after sowing north central Florida seeds, germination was similar among spring, summer and fall treatments (28.9 to 41.1%), but was reduced by the winter temperature (10.7%). South Florida seeds showed greatest germination under the fall temperature (71.2%), and the least germination under the summer temperature (30.2%). Additional seed treatments including applications of gibberellic acid (GA3) with kinetin nominally improved germination by 1.2 times compared to non-treated seed. Seeds tolerated cryopreservation treatments, including combinations of a plant vitrification solution, liquid nitrogen, phloroglucinol and precooling, suggesting long-term storage capability. As an alternative to seed propagation, cutting propagation was found to be a reliable means of reproducing wild lime with 91.0% rooting success when softwood cuttings were treated with 8,000 mg·kg−1 (0.13 oz·lb−1) indole-butyric acid (IBA), compared to 3,000 mg·kg−1 (0.05 oz·lb−1) IBA (86.3%) or the non-treated control (71.2%). Species used in this study: Wild lime, Zanthoxylum fagara (L. Sarg). Chemicals used in this study: 2,3,5-triphenyl-2H-tetrazolium chloride (TZ); sodium hypochlorite solution (Clorox bleach); gibberellic acid (GA3); kinetin (kinetin), plant vitrification solution 2 (PVS2); liquid nitrogen (LN); phloroglucinol (phloroglucinol); glycerol (glycerol); dimethyl sulfoxide (DMSO); MS media (Murashige and Skoog media), sucrose (sucrose); 15N-5P-15K liquid fertilizer (Peters Excel Cal-Mag Special); indole-3-butyric acid (IBA); 14N-14P-14K slow-release fertilizer (Osmocote).

Bilberry metabolomic and proteomic profiling during fruit ripening reveals key dynamics affecting fruit quality.

Bilberry (Vaccinium myrtillus L.) is a wildberry species that is prevalent in northern Europe. It is renowned and well-documented for its nutritional and bioactive properties, especially due to its anthocyanin content. However, an overview of biological systems governing changes in other crucial quality traits, such as size, firmness, and flavours, has received less attention. In the present study, we investigated detailed metabolomic and proteomic profiles at four different ripening stages of bilberry to provide a comprehensive understanding of overall quality during fruit ripening. By integrating omics datasets, we revealed a novel global regulatory network of plant hormones and physiological processes occurring during bilberry ripening. Key physiological processes, such as energy and primary metabolism, strongly correlate with elevated levels of gibberellic acids, jasmonic acid, and salicylic acid in unripe fruits. In contrast, as the fruit ripened, processes including flavour formation, cell wall modification, seed storage, and secondary metabolism became more prominent, and these were associated with increased abscisic acid levels. An indication of the increase in ethylene biosynthesis was detected during bilberry development, raising questions about the classification of non-climacteric and climacteric fruits. Our findings extend the current knowledge on the physiological and biochemical processes occurring during fruit ripening, which can serve as a baseline for studies on both wild and commercially grown berry species. Furthermore, our data may facilitate the optimization of storage conditions and breeding programs, as well as the future exploration of beneficial compounds in berries for new applications in food, cosmetics, and medicines.

Influence of gibberellic acid on leaf abscission and quality of sweet basil

Influence of gibberellic acid on leaf abscission and quality of sweet basil

DNA demethylation is involved in nitric oxide-induced flowering in tomato

Flowering is one of the most important phenological periods, as it determines the timing of fruit maturation and seed dispersal. To date, both nitric oxide (NO) and DNA demethylation have been reported to regulate flowering in plants. However, there is no compelling experimental evidence of the relationship between NO and DNA demethylation during plant flowering. In this study, an NO donor and a DNA methylation inhibitor were used to investigate the involvement of DNA demethylation in NO-mediated tomato (Solanum lycopersicum cv. Micro-Tom) flowering. The results showed that the promoting effect of NO on tomato flowering was dose-dependent, with the most positive role observed at 10 μmol L-1 of the NO donor S-nitrosoglutathione (GSNO). Treatment with 50 μmol L-1 of the DNA methylation inhibitor 5-azacitidine (5-AzaC) also significantly promoted tomato flowering. Moreover, GSNO and 5-AzaC increased the peroxidase (POD) and catalase (CAT) activity and cytokinin (CTK) and proline contents, while they decreased the gibberellic acid (GA3) and indole-3-acetic acid (IAA) contents. Co-treatment with GSNO and 5-AzaC accelerated the positive effects of GSNO and 5-AzaC in promoting tomato flowering. Meanwhile, compared with GSNO or 5-AzaC treatment alone, co-treatment with GSNO+5-AzaC significantly increased the global DNA demethylation levels in different tissues in tomato. The results also indicate that DNA demethylation may be involved in NO-induced flowering. The expression of flowering genes was significantly altered by the GSNO+5-AzaC treatment. Among these genes, five flowering induction genes-ARGONAUTE 4 (AGO4A), SlSP3D/SINGLE FLOWER TRUSS (SFT), MutS HOMOLOG 1 (MSH1), ZINC FINGER PROTEIN 2 (ZFP2), and FLOWERING LOCUS D (FLD) were selected as candidate genes for further study. Then, McrBC-PCR analysis showed that the DNA demethylation of the SFT gene in the apex and the FLD gene in the stem might be involved in NO-induced flowering. Therefore, our study shows that NO might promote tomato flowering by mediating the DNA demethylation of flowering induction genes. This study provides direct evidence of a synergistic effect of NO and DNA demethylation in promoting tomato flowering.

Gibberellic acid modulates the expression of flowering-related genes and the flower bud rate in apple (Malus domestica)

Gibberellic acid modulates the expression of flowering-related genes and the flower bud rate in apple (<i>Malus domestica</i>)

Hormone type, soaking duration and seed coating affect dormancy and germination of pennycress (Thlaspi arvense) lines

Establishment of pennycress is key to ensure uniform stands and maximise canopy closure in autumn. Past work has demonstrated that selected seed treatments could improve germination and establishment, but the optimisation of these processes to minimise inputs and time have not been assessed. The objective of this work was to evaluate seed enhancement technologies (hormone application by soaking and seed coating) to overcome seed dormancy and/or enhance germination. Two black-seeded lines (‘MN106NS’ and ‘ARV1’) and one golden-seeded line (‘tt8-t/ARV1’) were examined. Seeds were soaked in gibberellic acid (GA4+7) or benzyladenine (6-BA), or distilled water for different durations (30, 60, 240 minutes) and compared to an unsoaked control. Results showed that the GA treatment significantly increased germination, particularly for ‘ARV1’ and ‘MN106NS’ lines. Seed coating increased seed diameter but did not enhance germination; instead, it hindered ‘tt8-t/ARV1’ germination by 99-100%. The study suggests soaking seeds for at least 30 minutes in a GA solution to improve germination in black-seeded lines, however, economic and logistical factors must be considered. None of the tested enhancements proved beneficial on the two seed lots of golden-seeded line ‘tt8-t/ARV1’ and further research is needed to examine more seed lots before conclusions can be made.

Physiological and Proteomic Analysis of Various Priming on Rice Seed under Chilling Stress.

Rice (Oryza sativa L.) cultivation using direct seeding is susceptible to chilling stress, particularly during seed germination and early seedling growth in the early season of a double cropping system. Alternatively, seed priming with various plant growth-promoting hormones is an effective technique to promote rapid and uniform emergence under chilling stress. Therefore, we evaluated the impact of gibberellin A3 (GA3) and brassinolide (BR) priming on rice seed emergence, examining their proteomic responses under low-temperature conditions. Results indicated that GA3 and BR increased the seed germination rate by 22.67% and 7.33% at 72 h and 35% and 15% at 96 h compared to the control (CK), respectively. Furthermore, proteomic analysis identified 2551, 2614, and 2592 differentially expressed proteins (DEPs) in GA, BR, and CK, respectively. Among them, GA exhibited 84 upregulated and 260 downregulated DEPs, while BR showed 112 upregulated and 102 downregulated DEPs, and CK had 123 upregulated and 81 downregulated DEPs. Notably, under chilling stress, both GA3 and BR are involved in peroxide metabolism, phenylpropanoid biosynthesis, and inositol phosphate metabolism, enhancing antioxidant capacity and providing energy substances for germination. In addition, GA3 triggers the specific regulation of stress responsive protein activation, GTP activation, and ascorbic acid biosynthesis and promotes the stability and integrity of cell membranes, as well as the synthesis of cell walls, providing physical defense for seeds to resist low temperatures. At the same time, BR triggers specific involvement in ribosome synthesis and amino acid synthesis, promoting biosynthetic ability and metabolic regulation to maintain plant life activities under low-temperature stress. Furthermore, the various genes' expression (OsJ_16716, OsPAL1, RINO1) confirmed GA3 and BR involved in peroxide metabolism, phenylpropanoid biosynthesis, and inositol phosphate metabolism, enhancing antioxidant capacity and providing energy substances for germination. This study provides valuable insights into how rice seed embryo responds to and tolerates chilling stress with GA3 seed priming.

Chitosan mitigated the adverse effect of Cd by regulating antioxidant activities, hormones, and organic acids contents in pepper (Capsicum annum L.)

Chitosan (CTS) is one of the natural healers’ alternatives to chemical products within the scope of good agricultural practices. It can be used in the improvement of agriculture (prevention of toxic metal uptake by plants) due to its chelating feature of metal ions. This study aims to investigate the effectiveness of chitosan in eliminating the negative effects of cadmium (Cd) stress on pepper (Capsicum annum L.). The results showed that Cd stress significantly decreased plant growth, chlorophyll content, and leaf water relative content, followed by an increase in proline, antioxidant enzyme activities, and abscisic acid (ABA) content. According to the results, Cd treatment (200 mg kg-1) significantly increased the aspartate, glutamate, asparagine, histidine, and phenylalanine content, while it significantly decreased the content of endogenous hormones such as gibberellic acid (GA), indole-3-acetic acid (IAA), and salicylic acid (SA). However, CTS application decreased the uptake of Cd and caused a decrease in hydrogen peroxide (H2O2), abscisic acid (ABA), and melondialdehyde (MDA) content, as well as an increase in plant performance, and GA, IAA, and SA content in the plants grown under Cd pollution compared to the ones treated with Cd and without CTS. This study suggests that CTS application helps pepper seedlings tolerate Cd stress through a decrease in Cd uptake, and an increase in amino acids and hormone content.

Untargeted metabolic analysis of Epaltes mexicana by LC-QTOF-MS: Terpenes with activity against human cancer cell lines

Epaltes mexicana is a plant widely used in traditional medicine and as a food in Mexico; however, its phytochemical and pharmacological studies are limited. This study aimed to identify the active secondary metabolites of Epaltes mexicana and determine its cytotoxic activity on cancer cell lines. Three organic extracts were obtained by maceration using n-hexane, dichloromethane, and methanol. The n-hexane extract was fractioned by simple column chromatography. Eight terpenes were annotated in collection 6 (C6) by LC-QTOF-MS using a gradient elution and Electrospray Ionization (ESI) in positive ion mode: 1) Gibberellin A15, 2) farfugin A, 3) dehydromyodesmone, 4) eremopetasitenin A1, 5) hydroxyisonobilin, 6) anhydrocinnzeylanine, 7) nigakilactone H and 8) taxodione. On the other hand, C6 showed a concentration-dependent cytotoxic effect on cancer cell lines MCF-7 (Emax = 74.69 ± 6.19 % and IC50 = 6.31 μg/mL), MDA-MB-231 (Emax = 79.28 ± 12.12 % and IC50 = 124.21 μg/mL), and SiHa (Emax = 82.96 ± 6.02 % and IC50 = 124.31 μg/mL). The C6 did not show a cytotoxic effect against DU-145 and non-cancerous cells from the mammary glands MCF-10A. These results indicate cytotoxic specificity on cancer cell lines and support the hypothesis that terpenes identified in E. mexicana must be investigated and developed for non-clinical and clinical trials as potential anti-cancer drugs.

Role of Gibberellic Acid (GA₃) in enhancing growth and yield of hydroponically grown lettuce (Lactuca sativa L.)

Role of Gibberellic Acid (GA₃) in enhancing growth and yield of hydroponically grown lettuce (Lactuca sativa L.)

Evaluating Seed Viability and Germination Enhancement through Plant Growth Hormones in Anogeissus latifolia (Roxb. exDC.) Wall. Ex Guill. &amp; Perr.

Aims: To evaluate the seed viability and enhancing germination percentage through plant growth hormones in Anogeissus latifolia. Study Design: A randomized complete block design was used to conduct the investigation. Place &amp; Duration of Study: Plant nursery, ICFRE- AFRI, Jodhpur, Rajasthan, India; between Feb 2023 and June 2023. Methodology: The viability test was analyzed using a 1% Tetrazolium chloride solution (TZ). About 50g seeds were pre-treated with Gibberellic acid (GA3) and Indole-3-Butyric acid (IBA) and hormones of concentrations 500, 750, and 1000 ppm each. 1000 pre-treated seeds of each treatment were sowed in the mother bed of the nursery and germination was recorded for up to 15 days. Further germination indices such as germination percentage, germination speed, mean germination time, root length, shoot length, allometric coefficient, and vigor index were calculated. Results: A. latifolia contained around 33.74±6.561% viable seeds, according to a viability analysis using a 1% TZ solution. An analysis of variance in the data revealed a substantial (P≤.001) impact of PGRs and their interaction with the indices under investigation. The best treatment overall was demonstrated by GA3 750 ppm concentration followed by GA3 1000 ppm and IBA 750 ppm concentrations. IBA 1000 ppm, however, showed a decreased effect on germination studies. Conclusion: Gibberellic acid overall had a beneficial effect on germination and all the studied indices. These hormonal treatments can be used to propagate the plant species for plantation, afforestation, or conservation purposes.

A novel mutation in non-constitutive lycopene beta cyclase (CstLcyB2a) from Crocus sativus modulates carotenoid/apocarotenoid content, biomass and stress tolerance in plants.

Mutation at A126 in lycopene-β-cyclase of Crocus (CstLcyB2a) sterically hinders its binding of δ-carotene without affecting lycopene binding, thereby diverting metabolic flux towards β-carotene and apocarotenoid biosynthesis. Crocus sativus, commonly known as saffron, has emerged as an important crop for research because of its ability to synthesize unique apocarotenoids such as crocin, picrocrocin and safranal. Metabolic engineering of the carotenoid pathway can prove a beneficial strategy for enhancing the quality of saffron and making it resilient to changing climatic conditions. Here, we demonstrate that introducing a novel mutation at A126 in stigma-specific lycopene-β-cyclase of Crocus (CstLcyB2a) sterically hinders its binding of δ-carotene, but does not affect lycopene binding, thereby diverting metabolic flux towards β-carotene formation. Thus, A126L-CstLcyB2a expression in lycopene-accumulating bacterial strains resulted in enhanced production of β-carotene. Transient expression of A126L-CstLcyB2a in C. sativus stigmas enhanced biosynthesis of crocin. Its stable expression in Nicotiana tabacum enhanced β-branch carotenoids and phyto-hormones such as abscisic acid (ABA) and gibberellic acids (GA's). N. tabacum transgenic lines showed better growth performance and photosynthetic parameters including maximum quantum efficiency (Fv/Fm) and light-saturated capacity of linear electron transport. Exogenous application of hormones and their inhibitors demonstrated that a higher ratio of GA4/ABA has positive effects on biomass of wild-type and transgenic plants. Thus, these findings provide a platform for the development of new-generation crops with improved productivity, quality and stress tolerance.

Quantitative Proteomics Analysis of ABA- and GA3-Treated Malbec Berries Reveals Insights into H2O2 Scavenging and Anthocyanin Dynamics.

Abscisic acid (ABA) and gibberellic acid (GA3) are regulators of fruit color and sugar levels, and the application of these hormones is a common practice in commercial vineyards dedicated to the production of table grapes. However, the effects of exogenous ABA and GA3 on wine cultivars remain unclear. We investigated the impact of ABA and GA3 application on Malbec grapevine berries across three developmental stages. We found similar patterns of berry total anthocyanin accumulation induced by both treatments, closely associated with berry H2O2 levels. Quantitative proteomics from berry skins revealed that ABA and GA3 positively modulated antioxidant defense proteins, mitigating H2O2. Consequently, proteins involved in phenylpropanoid biosynthesis were downregulated, leading to decreased anthocyanin content at the almost ripe stage, particularly petunidin-3-G and peonidin-3-G. Additionally, we noted increased levels of the non-anthocyanins E-viniferin and quercetin in the treated berries, which may enhance H2O2 scavenging at the almost ripe stage. Using a linear mixed-effects model, we found statistical significance for fixed effects including the berry H2O2 and sugar contents, demonstrating their roles in anthocyanin accumulation. In conclusion, our findings suggest a common molecular mechanism by which ABA and GA3 influence berry H2O2 content, ultimately impacting anthocyanin dynamics during ripening.