Guar Plants Research Articles

Endophytic bacilli from Cyamopsis tetragonoloba (L.) Taub. induces plant growth and drought tolerance.

Cyamopsis tetragonoloba (L.) Taub. (guar) is a commercially important crop known for its galactomannan content in seeds. Drought stress is a significant global concern that compromises the productivity of major legumes including guar. The endophytic microbes associated with plants play a significant role in enhancing plant growth and modulating the impact of abiotic stress(s). The present study involved the isolation of 73 endophytic bacteria from the guar seeds of drought-tolerant (RGC-1002 and RGC-1066) and sensitive (Sarada and Varsha) varieties. Based on multiple PGP attributes and drought tolerance, at 50% PEG6000 w/v, 11 efficient isolates were selected and identified through 16S rRNA gene sequencing. Isolates belonging to ten different species of bacilli including Cytobacillus oceanisediminis, Mesobacillus fermenti, Peribacillus simplex from sensitive and Bacillus zanthoxyli, B. safensis, B. velezensis, B. altitudinis, B. licheniformis, B. tequilensis, and B. paralicheniformis isolated from tolerant varieties. A greenhouse experiment with a drought-sensitive guar variety demonstrated that inoculation of selected isolates showed comparatively better plant growth, higher relative water content (RWC), decreased carbon isotope discrimination ratio (Δ13C), increased chlorophyll, carotenoids, anthocyanin, and proline content, decreased malondialdehyde (MDA) and modulated defense enzymes as compared to their uninoculated controls. Tolerant variety isolates B. tequilensis NBRI14G and B. safensis NBRI10R showed the most promising results in improving plant growth and also drought stress tolerance in guar plants. This study represents for the first time that seed endophytic bacterial strains from guar can be utilized to develop the formulation for improving the productivity of guar under drought-stress conditions.

Mitigating gadolinium toxicity in guar (Cyamopsis tetragonoloba L.) through the symbiotic associations with arbuscular mycorrhizal fungi: physiological and biochemical insights

BackgroundGadolinium (Gd) is an increasingly found lanthanide element in soil; thus, understanding its impact on plant physiology, biochemistry, and molecular responses is crucial. Here, we aimed to provide a comprehensive understanding of Gd (150 mg kg− 1) impacts on guar (Cyamopsis tetragonoloba L.) plant yield and metabolism and whether the symbiotic relationship with arbuscular mycorrhizal fungi (AMF) can mitigate Gd toxicity of soil contamination.ResultsAMF treatment improved mineral nutrient uptake and seed yield by 38–41% under Gd stress compared to non-inoculated stressed plants. Metabolic analysis unveiled the defense mechanisms adopted by AMF-treated plants, revealing carbon and nitrogen metabolism adaptations to withstand Gd contamination. This included an increase in the synthesis of primary metabolites, such as total sugar (+ 39% compared to control), soluble sugars (+ 29%), starch (+ 30%), and some main amino acids like proline (+ 57%) and phenylalanine (+ 87%) in the seeds of AMF-treated plants grown under Gd contamination. Furthermore, fatty acid and organic acid profile changes were accompanied by the production of secondary metabolites, including tocopherols, polyamines, phenolic acids, flavones, and anthocyanins.ConclusionsOverall, the coordinated synthesis of these compounds underscores the intricate regulatory mechanisms underlying plant-AMF interactions and highlights the potential of AMF to modulate plant secondary metabolism for enhanced Gd stress tolerance.

Evaluation of collection specimens of guar (Cyamopsis tetragonoloba L.) by economically valuable traits

For effective introduction of guar into production, it is necessary to use varieties adapted to the Southern Steppe of Ukraine, the creation of which is impossible without well-researched collection material, which is relevant and important. Guar is in high demand globally in the food and oil industries, and most importantly, thanks to its ability to symbiotically fix nitrogen, it improves soil quality in a cost-effective and natural way. However, it is a completely new culture for Ukraine. The purpose of this study was to investigate the gene pool of guar plants and identify the best ones with economically valuable traits. The study used field, laboratory, and statistical methods. The results of the study conducted in 2020-2022 helped to identify the best introduced guar samples in terms of tolerance to hot temperatures and the arid climate of the Southern Steppe of Ukraine. The most adapted to this zone are IU07466 Haldi bhati and IU074658 Pusa Naubahar. They formed the maximum yields: IU07466 Haldi bhati – 262.5 g/m2 , IU074658 Pusa Naubahar – 329.0 g/m2 , which is more than 135% compared to the standard. The above-mentioned samples were characterised by a vegetation period of 133.5 days and 129.5 days, respectively, which, on average, over two years of research, exceeded the duration of the “germination – maturation” period of the standard variety IU074657 Ankur by 4.5-8.5 days. The correlation and regression analysis of the data obtained from the study of the introduced samples of the guar gene pool suggested a direct correlation between the weight of seeds per square metre and the number of beans and seeds per plant. The correlation coefficient is 0.997-0.986, respectively. It is recommended to use the identified sources of valuable traits for further effective implementation in the breeding and research programmes of scientific institutions to create self-pollinated lines, synthetic populations, varieties adapted to the extreme conditions of the Southern Steppe of Ukraine

Melatonin mitigation of herbicide-induced injury to guar crop improves nodulation

The guar plant, or cluster bean, forms a weak symbiosis with rhizobia, and it is sensitive to herbicides. We hypothesized that application of melatonin to guar seeds, leaves, or both protect against metabolic injury from eight herbicides, and strengthening the symbiosis. Imazethapyr and 2,4-DB did not injure guar and its rhizobium partner. Root nodulation was severely damaged with pendimethalin and less with bentazon. A reduction in guar's total dry weight, which ranged from 14% with bentazon to 28% with bromoxynil, was observed, indicating metabolic stress. When no herbicide was applied, seeds coated with melatonin had no effect. When herbicides were applied, it partially mitigated herbicide-induced injury. Foliar application of melatonin protected guar completely against bentazon, bromoxynil, and oxyfluorfen, protected nodulation.

A preliminary study on heavy metal monitoring in soil and guar (Cyamopsis tetragonoloba) biomass amended with sewage sludge.

Applying sewage sludge in agricultural soils is an interesting source of organic matter. This study aimed to monitor concentrations of heavy elements in soil and guar plants, which can pose a risk to the health of humans and animals if they enter the food chain through the soil-plant system. The experiment revealed that applying sludge increased the amount of organic matter, total nitrogen, potassium, and phosphorus in the soil. Additionally, the concentration of heavy metals such as Pb, Co, Cr, Ni, Cu, and Zn in all treatments remained below the permissible limits for soil. The highest plant height and plant dry weight were recorded in the sludge and sludge + fertilizer treatments. The dry weight of the guar varied from 629 g m-1 in the control treatment to 1050 g m-1 in the sludge + fertilizer plots. The use of sludge increased the accumulation of heavy metals in the above-ground parts of the guar plant compared to the control. However, the level of heavy metal remained within the normal range and below the toxic concentration. Our results also showed that the application of sludge along with fertilizer improved the quality of the guar forage by increasing the levels of crude protein, digestible dry matter and water-soluble carbohydrates. Overall, the results indicated that using sludge as organic fertilizer can improve soil properties, reduce the use of inorganic fertilizers, and decrease the harmful effects of heavy metals on the environment and health in the research area.

Alterations in plant anatomy and higher lignin synthesis provides drought tolerance in cluster bean [Cyamopsis tetragonoloba (L.) Taub.

Four contrasting varieties of guar, RGC-1002 and RGC-1038, drought tolerant, while, Sarada and RGC-936, drought sensitive, were monitored in watered and drought. The water status, phenolics, plant anatomy and transcript level of genes related to anatomical traits were assessed. The study aimed to decipher the anatomical adaptations of guar plants in response to water stress. The physiological determinants, relative water content (RWC), water potential (ψ), and leaf membrane damage, declined under drought in all four varieties although, the decrement was lesser in the tolerant varieties. Furthermore, the tolerant cultivars subjected to water stress recorded higher accumulation of total phenolic content, anthocyanin and lignin, which efficiently scavenge the reactive oxygen species. The results suggest that the cultivars RGC-1002 and RGC-1038 are better able to resist drought-induced oxidative stress than Sarada and RGC-936. Moreover, leaf, petiole, stem and root anatomical traits viz. size of epidermal cell, parenchyma, width of cortex layer, and diameter of xylem vessels were narrowed in all the varieties although, the decrement was lesser in the tolerant varieties under drought. The expression analysis of genes revealed that drought-tolerant varieties showed enhanced mechanical support for water conduction by up-regulation of genes, Phenylalanine ammonia-lyase1 (PAL1), cinnamate-4-hydroxylase (C4H), 4-coumarate-CoA ligase (4CL), cinnamoyl-CoA reductase (CCR), caffeoyl-CoA O-methyltransferase (CCOMT), and cinnamyl-alcohol dehydrogenase (CAD6) in water stress conditions. The alterations in physio-anatomical, biochemical and gene expression traits in tolerant guar varieties enabled them to maintain steady nutrient transport while reducing the risk of embolisms and increasing water-flow resistance for better survival in water stressed conditions.

Identification and characterization of the Cyamopsis tetragonoloba transcription factor MYC (CtMYC) under drought stress

The MYC transcription factor (TF) has a variety of roles in abiotic stress responses of plants. In the present work, MYC TF named CtMYC (Cymopsis tetragonoloba) from guar plant, which is induced by drought stress, was identified. The mature leaves of guar were employed to detect the full-length CtMYC TF on the 8th day of drought stress. The CtMYC gene showed tissue-specific expression and up regulated under drought stress conditions as compared to the control and maximum expression was observed in mature leaves. Additionally, CtMYC TF was cloned and expressed in E. coli Rosetta cells and CtMYC protein was purified. The circular dichroism (CD) analysis revealed the presence of helical content and beta sheets and in the presence of genomic DNA the conformational changes were observed in secondary structure, which showed DNA binding potential of CtMYC. These results were analyzed by CD and fluorescence studies. In silico studies reveal the presence of conserved bHLH domain and DNA-binding amino acid residues His, Glu and Arg in CtMYC. This is first report on CtMYC TF with DNA binding potential that is responsive to drought. This study provides the structure and characterization of CtMYC TF and DNA binding ability in drought tolerance mechanism in guar.

Combination Influences of NPK Fertilizers and Bradyrhizobium Inoculation on the Yield, Chemical Constituents and Guaran Production of Guar (Cyamopsis tetragonoloba, Taub.) Plant

At the Experimental Farm (Ghazala Farm) of the Agric. Fac., Zagazig University, Egypt, two field experiments were conducted through the two successive summer seasons in 2019 and 2020. This was an effort to improve the guar plant’s yield and productivity. The experiment was set up as a split-plot design with NPK fertilization as the main plot and bio-fertilization as the sub-plot. The Bradyrhizobium spp. inoculation rates were (0.0, 200 and 400 g/feddan), while the NPK fertilization levels were (0.0, 75, 100, and 125% of recommended level). Ammonium sulphate (20.5% N) at 200 kg/feddan, calcium super phosphate (15.5% P2O5) at 200 kg/feddan, and potassium sulphate (48% K2O) at 100 kg/feddan were the NPK fertilization recommended rates (RR). The obtained results showed that, in comparison to control and the other levels under study, guar plants fertilized with 125% RR significantly increased yield components as well as total carbohydrates content, and NPK percentages in seeds and guaran production. Additionally, compared to the control and lowest inoculation rates of Bradyrhizobium, the maximum inoculation rate (400 g/feddan) considerably recorded the highest values of all the aforementioned parameters. The majority of the study’s findings demonstrated that fertilized guar plants with 125% RR of NPK fertilization, together with 400 g/feddan of Bradyrhizobium inoculation rate, might aid to improve guar plant (Cyamopsis tetragonoloba Taub.) yield, chemical constituents and guaran production.

The effects of microbial fertilizers application on growth, yield and some biochemical changes in the leaves and seeds of guar (Cyamopsis tetragonoloba L.)

Guar (Cyamopsis tetragonoloba L.) is a summer legume that is becoming a crucial industrial crop because of its high gum and protein content. Thus far, the combined effects of arbuscular mycorrhizal fungi (AMF) and Bradyrhizobium on the yield and chemical composition of guar plants are not well studied. Therefore, the current investigation was designed to estimate the individual as well as the combined effects of AMF and Bradyrhizobium on plant growth, yield and nutritional quality of seeds and leaves of guar. AMF and/or Bradyrhizobium inoculation improved chemical composition of guar seeds and its morpho-physiological (plant height, fresh weight, dry weight, and yield production) traits. In addition to increased guar growth and yield production, the inoculation of AMF and/or Bradyrhizobium increased guar leaf and seed minerals, fiber, lipids, crude protein and ash contents. At primary metabolites, there were increases in sugar levels including raffinose stachyose, verbascose and galactomannan. These increases in sugar provided a route for organic acids, amino acids and fatty acids production. Interestingly, there was an increase in essential amino acids and unsaturated fatty acids. At the bioactive secondary metabolite levels, biofertilizers improved phenols and flavonoids levels and anthocyanin and polyamines biosynthesis. In line with these increases, precursors of anthocyanin (phenylalanine, p-coumaric acid, and cinnamic acid) and the levels of polyamines (diaminopropane, putrescine, cadaverine, spermidine, spermine, and agmatine) were increased. Overall, for the first time, our study shed the light on how AMF and Bradyrhizobium improved guar yield and metabolism. Our findings suggested that the combined inoculation of AMF and Bradyrhizobium is an innovative approach to improve guar growth, yield production and yield quality.

Green synthesized guar plant composites for wastewater remediation: a comprehensive review

Green synthesized guar plant composites for wastewater remediation: a comprehensive review

Occurrence of Curvularia pisi and C. muehlenbeckiae Causing Leaf Spot on Guar (Cyamopsis tetragonoloba) in Mexico.

Cyamopsis tetragonoloba (Fabaceae family), known as guar or clusterbean, is a drought-tolerant annual legume cultivated on a commercial scale focused on industrial gum production. In September 2021, symptoms of leaf spot were observed on guar plants in several commercial fields located at Guasave, Sinaloa, Mexico. Symptoms included round to oval, light brown lesions with dark margins. The disease incidence was estimated to be up to 30% in five fields. Curvularia-like colonies were consistently isolated, and 12 monoconidial isolates were obtained. Two representative isolates were selected to use downstream and were deposited in the Culture Collection of Phytopathogenic Fungi of the Faculty of Agriculture of Fuerte Valley at the Sinaloa Autonomous University under Accession FAVF643 and FAVF645. On potato dextrose agar (PDA), colonies of both isolates FAVF643 (pale brown margin) and FAVF645 (lobate edge) were dark brown. Conidiophores of both isolates FAVF643 (paler towards apex and 76 to 191 × 3.5 to 5.2 μm) and FAVF645 (80 to 260 × 3.9 to 5.1 μm) were mostly straight, pale brown to dark brown, septate, and simple to branched. Conidia of both isolates FAVF643 (19.9 to 33.3 × 8.8 to 13.5 μm) and FAVF645 (18.5 to 27.1 × 9.1 to 13.1 μm) were curved, rarely straight, brown, with apical and basal cells paler than middle cells being pale brown, and 3-distoseptate. Morphology of both isolates FAVF643 and FAVF645 was consistent with that described for Curvularia (Marin-Felix et al. 2017; 2020). For phylogenetic identification, total DNA was extracted and PCR products sequenced from ITS5/ITS4 primers -the internal transcribed spacer (ITS) region (White et al. 1990) and GPD1/GPD2 - partial sequences of glyceraldehyde-3-phosphate dehydrogenase (gpdh) gene amplification. A phylogenetic tree based on Maximum likelihood including published ITS and gpdh for Curvularia spp. was constructed. Phylogenetic analyses showed that isolate FAVF643 grouped with the type strain C. pisi (CBS190.48) sequence, and the isolate FAVF645 grouped with the type strain C.muehlenbeckiae (CBS144.63) sequence. The resulting sequences were deposited in GenBank as: C. pisi OM802153 (ITS); OM835758 (gpdh), and C. muehlenbeckiae OM802154 (ITS); OM835759 (gpdh). The pathogenicity was verified on healthy guar plants. For each isolate, five plants were inoculated by spraying a conidial suspension (1 × 106 spores/ml) onto leaves until runoff. Five plants sprayed with sterile distilled water served as controls. All plants were kept in a moist chamber for two days, and subsequently transferred to a greenhouse for 12 days at temperatures ranging from 26 to 32°C. All inoculated leaves exhibited necrotic lesions with a dark margin 10 days after inoculation, whereas control plants remained symptomless. The fungi were consistently re-isolated from the diseased leaves and found to be morphologically identical to the isolates used for inoculation, fulfilling Koch´s postulates. Curvularia lunata had been reported as the causal agent of leaf spot on guar in India (Chand and Verma 1968); however, to our knowledge, this is the first report of C. pisi and C. muehlenbeckiae causing leaf spot on guar in Mexico and worldwide.

GAMMA-RAYS AND MICROWAVES IRRADIATION INFLUENCE ON GUAR (CYAMOPSIS TETRAGONOLOBA): II – PROTEOMIC ANALYSIS LINKED TO PLANT HEIGHT AND CRUDE PROTEINS

Guar is an economically significant forage crop and a multi-purpose plant. In Egypt, with a limited gene pool of guar, gamma ray (γ-rays) and microwave pre-treatment, individually or in association, were used to generate genetic variability and develop new high-yielding genotypes. Guar seeds of the variety Shandaweel-9 were irradiated with different γ-ray doses (i.e., 0, 150, 250, and 350 Gray “Gy”), either individually or along with the irradiation with 900 W microwave treatments applied for different exposure times (1, 2, 3, and 4 min), then grown at Agricultural Research Center, Giza, Egypt in 2019, and 2020 summer seasons. The results indicated that gamma-ray doses of 150 and 250 Gy, stand-alone or with microwave treatments, significantly influenced guar plant height and crude protein in M1 and M2. Fragments with 925, 1427, and 2145 bp linked to plant height and crude protein were eluted from the gel, sequenced, and then registered on GenBank. The fragment linked to plant height received accession No. LC681484.1 and fragments linked to crude protein received accession No. of OK617330.1 and OK617331.1. The sequenced fragments underwent translation to protein, then proceeded to proteome analyses. Depending on the sequence analysis, the 925 bp fragment consisted of a 302 bp ORF (open reading frame) encoded with 302 amino acids. However, the fragment of 1427 bp has 433 ORF, and the fragment of 2145 bp has 705 ORF. The LC681484.1 might have a role in plant elongation. On the other hand, OK617330.1 and OK617331.1 might be responsible for cell wall protein organization.

First Report of Sclerotium rolfsii Causing Collar Rot of Guar (Cyamopsis tetragonoloba) in Mexico.

Cyamopsis tetragonoloba (Fabaceae), also known as guar or cluster bean, is an annual legume grown mainly for industrial purposes and also as an ingredient for animal feed. In October 2021, collar rot symptoms were observed in five guar fields located in Guasave, Sinaloa, Mexico. Abundant white mycelium, and later brown and small sclerotia were observed at the base of the stems. Diseased plants showed reduced growth, wilting, and drying of the entire plant. Disease incidence ranged from 15 to 40%. Samples were collected from each field at two phenological stages (vegetative and reproductive). For fungal isolation, symptomatic stems pieces were surface sterilized with 2% sodium hypochlorite for 2 min, rinsed in sterilized distilled water two times, placed on PDA medium and incubated at 28°C in darkness for 3 days. Sclerotium-like colonies were consistently obtained and five isolates from five different fields were purified by the hyphal-tip method. Fungal colonies were white, cottony, and often forming fans. Sclerotia (1 to 2 mm diameter) were white at first and then gradually turned dark brown. Microscopic examination showed septate hyphae with some cells having clamp connections. A representative isolate was deposited in the Culture Collection of Phytopathogenic Fungi of the Faculty of Agriculture of Fuerte Valley at the Sinaloa Autonomous University under Accession no. FAVF647. For molecular identification, genomic DNA was extracted, and the internal transcribed spacer (ITS) region was amplified by PCR and sequenced using the primer pair ITS5/ITS4 (White et al. 1990). The sequence was deposited in GenBank (accession no. OM510466). BLASTn searches in GenBank showed 99.21 to 100% identity with the available sequences of Sclerotium rolfsii (accession nos. MK926446, MH854711, and KY175225). A phylogenetic analysis using the maximum Likelihood method placed isolate FAVF647 in the same clade as S. rolfsii. Pathogenicity tests were performed by inoculating 10 healthy guar seedlings (15-day-old) grown in pots. Four sclerotia were directly placed on the stem base of each plant. Five uninoculated guar seedlings were used as control. All plants were placed in a moist chamber at 25°C with a 12-h photoperiod for 2 days. Collar rot symptoms appeared on inoculated plants after 3 days, whereas control plants remained symptomless. Pathogenicity test was performed twice with similar results. The fungus was reisolated from the artificially inoculated plants, thus fulfilling Koch's postulates. Sclerotium rolfsii has been reported on guar plants in Australia, Brazil, Fiji, India, and the United States (Farr and Rossman 2022). To our knowledge, this is the first report of Sclerotium rolfsii causing collar rot of guar in Mexico. The disease is very common in guar fields in Sinaloa, Mexico, therefore additional studies are needed to develop effective disease-management strategies.

Growth, seed yield and guran yield of guar plants as affected by using cattle manure and some stimulant substances

Growth, seed yield and guran yield of guar plants as affected by using cattle manure and some stimulant substances

Photosynthesis in guar: Recovery from water stress, basic parameter estimates, and intrinsic variation among germplasm

ABSTRACT Little is known about the photosynthetic physiology of guar (Cyamopsis tetragonoloba L. Taub), a legume crop, including how photosynthetic parameters intrinsically vary among germplasm and their recovery from water stress. To address this, two greenhouse studies were conducted: Study-1 to compare photosynthetic light response (A N–I) curves and related parameters in three contrasting guar genotypes under optimal and post-water deficit conditions; and Study-2 to quantify photosynthetic parameters in 44 guar genotypes and explore inter-relationships with plant growth parameters. In Study-1, the mean net photosynthetic rate (A N) statistically peaked with 1500 μmol (photons) m −2 s −1, though the maximum A N [33.29 μmol (CO2) m−2 s−1] was modeled to occur with 1950 μmol (photons) m −2 s −1. The light compensation point (I comp), dark respiration rate (R D), and maximum quantum yield (Ф(I 0)) were modeled to be 49.9 μmol (photons) m−2 s−1, 2.62 μmol (CO2) m−2 s−1, and 0.0526 μmol (CO2) μmol −1 (photons), respectively. Photosynthesis in guar was resilient to water stress. Despite reductions in growth, specific leaf area (SLA), and other growth parameters, persistently drought-stressed guar plants, on average, exhibited rapid and full recovery of photosynthetic functions when watered. Genotypes differed in their capacity to recover to some degree. In Study-2, A N differed only between two of the 44 genotypes tested, corresponding to the minimum and maximum A N values. There were no relationships between A N and most plant growth parameters. This finding suggested there is low potential to use point measurements of A N as a selection parameter for increased guar productivity.

Synchronised interaction of carbon and nitrogen provides drought tolerance in Cyamopsis tetragonoloba

Drought is a major adverse environmental factor that limits plant productivity. Concomitant assimilation of carbon (C) and nitrogen (N) in illuminated leaves requires the regulated partitioning of reductant and photosynthate to sustain the demands of amino acid and carbohydrate biosynthesis. The short-term exposure to drought and its responses of photosynthesis and photosynthate partitioning to N enrichment was studied in Cyamopsis tetragonoloba (L.) Taub (guar). Four contrasting varieties of guar, HG-563, RGC-986 (drought-tolerant) and RGC-471, Varsha (drought-sensitive) were subjected to 15 days water stress and leaf tissues were studied in order to contemplate the counter strategy engaged under drought conditions. In guar plants, sensors trigger a signalling cascade that activates numerous proteins to induce the expression of certain genes involved in carbon and nitrogen metabolism.The levels of glucose, starch, and Glutamate dehydrogenase (GDH), Aspartate aminotransferase (AspAT), isocitrate dehydrogenase (ICDH), Nitrate Reductase (NR), and Nitrite reductase (NiR) activities were determined biochemically during 15 days drought treatment, at three stages. Further, the carbon (oxidative phosphorylation and TCA cycle) - nitrogen metabolic pathway interaction was studied at the molecular level. The respiratory pathway genes were upregulated, while the nitrogen metabolic pathway genes were downregulated under all stages of drought in guar plants. The physiological, biochemical and molecular data suggests that the high rates of dark respiration was insufficient to provide extra carbon required to assist amino acid synthesis but rather sufficed by a rapid metamorphosis in the photosynthetic carbon partitioning to amino acid metabolism via the nitrogen metabolism. • Drought causes NADH DEHYDROGENASE gene to escalate dark respiration. • Nitrogen assimilation reduces under drought in leguminous Cyamopsis tetragonoloba. • Drought triggers protein kinase cascade signalling in guar plants. • Drought regulates nitrogen metabolic genes in guar. • Drought triggers increase in sugar content at the cost of amino acids.

GAMMA-RAYS AND MICROWAVE IRRADIATION INFLUENCE ON GUAR (CYAMOPSIS TETRAGONOLOBA): I - MARKERS ASSISTED SELECTION FOR RESPONDING TO MUTAGENIC AGENTS

The recent investigation was carried out to determine the effect of different gamma-ray doses and 900 W (2450 MHz) microwave radiation with various exposure times, separately or in combinations, on the yield, yield components, and chemical properties of guar (Cyamopsis tetragonoloba), as well as, to detect variation induction. The cDNA-SCoT technique was used to obtain molecular markers related to some traits. SSR technique was used to sequence the target fragment related to plant height. Gamma-ray doses of 150 and 250 Gy alone, and in combination with 900 W microwaves irradiation applied with different duration or time span (1, 2, 3, and 4 min) influenced the plant height significantly, as well as, number of tillers plant-1 and fresh and dry forage yield, and fresh and dry leaf stem-1 ratio. In the second sample, seed yield at harvest time, e.g., pods plant-1, weight of pods plant-1, whole plant dry weight, number of seeds pod-1, length of pod, 100-seed weight, and seeds yield were affected by irradiation with different and varied responses. In the M1 generation, the 18 SCoT primers produced 327 bands ranging between 151–2895 bp in size, out of which 282 were polymorphic (86.24%). In the M2, the 18 SCoT primers produced 328 bands ranging between 212–2661 bp in size, out of which 299 were polymorphic (91.16%). The M1 and M2 generations exhibited 89 positive and 39 negative bands, which could be used as marker assisted-selection in response to treated guar plants with different gamma ray doses, separately or in combinations with microwave treatments.

A Comparison of the Transglycosylation Capacity between the Guar GH27 Aga27A and Bacteroides GH36 BoGal36A α-Galactosidases

The transglycosylation behavior and capacity of two clan GH-D α-galactosidases, BoGal36A from the gut bacterium Bacteroides ovatus and Aga27A from the guar plant, was investigated and compared. The enzymes were screened for the ability to use para-nitrophenyl-α-galactoside (pNP-Gal), raffinose and locust bean gum (LBG) galactomannan as glycosyl donors with the glycosyl acceptors methanol, propanol, allyl alcohol, propargyl alcohol and glycerol using mass spectrometry. Aga27A was, in general, more stable in the presence of the acceptors. HPLC analysis was developed and used as a second screening method for reactions using raffinose or LBG as a donor substrate with methanol, propanol and glycerol as acceptors. Time-resolved reactions were set up with raffinose and methanol as the donor and acceptor, respectively, in order to develop an insight into the basic transglycosylation properties, including the ratio between the rate of transglycosylation (methyl galactoside synthesis) and rate of hydrolysis. BoGal36A had a somewhat higher ratio (0.99 compared to 0.71 for Aga27A) at early time points but was indicated to be more prone to secondary (product) hydrolysis in prolonged incubations. The methyl galactoside yield was higher when using raffinose (48% for BoGal36A and 38% for Aga27A) compared to LBG (27% for BoGal36A and 30% for Aga27A).

Guar (Cyamopsis tetragonoloba [L.] Taub.) response to organic and inorganic nitrogen sources during early seedling growth

Guar (Cyamopsis tetragonoloba [L.] Taub.), a legume, has gained its industrial importance due to galactomannan gum in its seed endosperm. As a legume guar Rhizobium nodulation is usually inadequate. Thus, it does not fix nitrogen sufficiently in the soil. Guar seeds were germinated under five concentrations each of organic {Bovine Serum Albumin (BSA)}, inorganic {Ca(NO3)2} and combined {(BSA + Ca(NO3)2} nitrogen sources in order to analyze the morphological, anatomical, and protein concentration changes due to different concentrations of varying nitrogen sources. Low nitrogen concentration in modified Hoagland’s solution in absence of preexisting nitrogen in the supporting solution (coco peat) showed significantly reduced morphological and anatomical characteristics and total protein concentration. On the other hand, the combination of organic and inorganic nitrogen sources showed greater effect on morphological, anatomical characters, and total protein concentration than individual treatments and control. At 16.1 mM nitrogen [given through combined treatment of 0.075 g/dL BSA + 0.095 g/dL Ca (NO3)2] metaxylem number (MXN), percent of stele that is metaxylem (percSisMX) and total protein concentration (TPC) were nearly equal or higher than the control. These parameters are positively correlated with each other which indicates that MXN, percSisMX and TPC contribute to relieve guar plant from nitrogen stress by more inflow of water and nutrients. Results show despite being a leguminous crop guar behaves as non-leguminous crop toward nitrogen and is affected by nitrogen stress during germination.

Green synthesis of copper nanoparticles extracted from guar seedling under Cu heavy-metal stress by Trichoderma harzianum and their bio-efficacy evaluation against Staphylococcus aureus and Escherichia coli

Copper nanoparticles were successfully synthesized with the help of agriculturally beneficial fungus Trichoderma harzianum through a simple green and eco-friendly route. The objectives of this study were to: (1) evaluate the application of T. harzianum and assess the effect of guar plant cultivation on heavy metal contaminated lands of copper in municipal and industrial wastewaters, and (2) develop a method to increase the antibacterial effects on the risk of two bacteria (Staphylococcus aureus and Escherichia coli). Two factors were investigated: (1) two copper (Cu) levels, Natural Hoagland Arnold solution as a control, and application of 100 μL Cu in Hoagland Arnold solution, and (2) two bio-fertilizer levels, no application, and fungus application. TEM and SEM photographs showed that synthesized Cu-NPs had spherical shapes. The formations of Cu-NPs were corroborated by FTIR and XRD analysis. Furthermore, the MIC and MBC of Cu-NPs towards bacterial growth were evaluated. The Cu-NPs and T. harzianum fungi presented antibacterial activity against Gram positive and Gram negative bacteria. The results suggested that green synthesis of nanoparticles using guar extracts can increase their antibacterial effect. The effect of Cu and fungi on biochemical properties of guar was also investigated. The results showed that the highest antioxidant enzymatic activity and proline amino acid were obtained at 100 μL Cu and T. harzianum application. Moreover, the results suggested that the use of T. harzianum can be useful in increasing the resistance to heavy metal stress in plants by increasing the activity of some antioxidant enzymes and secondary metabolites.