Max Cv Research Articles

Biochar amendment shifts bacterial keystone taxa regulating soil phosphorus dynamics

Biochar amendment can improve soil phosphorus (P) availability, yet the influence of microbial community structure, especially certain keystone taxa on P dynamics remains uncertain. A pot experiment was conducted on a highly weathered Ferralsol to investigate how the amendment with biochar and P-fertilizer (CK, no biochar and P addition; PP, 30 kg P ha−1 addition; BC, 4 % biochar addition and BP, 30 kg P ha−1 combined with 4 % biochar addition) affect soybean (Glycine max (L.) cv. Huaxia-9) P uptake, soil P dynamics and its association with bacterial community structure and keystone taxa. The biochar-amended treatments (BC and BP) led to a 50–130 % increase in P uptake and a ten-fold rise in labile P proportion compared to treatments without biochar (CK and PP). This could be associated with the incorporation of P from biochar, as well as the altered soil P availability by elevated soil pH, soil organic carbon (SOC), microbial biomass P and alkaline phosphatase activity. Furthermore, biochar amendments altered bacterial community composition by increasing the relative abundance of Gemmatimonadetes, Bacteroidetes and Verrucomicrobia phylum by over three-fold, while decreasing the relative abundance of Chloroflexi and Acidobacteria phylum by over 50 %, compared to the non-biochar treatments. Additionally, the elevated C:P ratio following biochar amendment played a dominant role in shaping the keystone taxa, which was identified as the primarily microbial predictor of soil labile P. Specifically, biochar amendment increased microbial network complexity, inducing a shift in keystone taxa from oligotrophs to copiotrophs, such as Rhizobiales, Sphingomonadales and Rhodospirillales, which are wildly recognized for their roles in soil P mobilization. Taken together, our findings suggested that biochar-induced shift in keystone taxa is one of the major predictors of soil P dynamics, highlighting the potential of harnessing specific keystone taxa for improving soil P availability.

Development of new mutant alleles and markers for KTI1 and KTI3 via CRISPR/Cas9-mediated mutagenesis to reduce trypsin inhibitor content and activity in soybean seeds.

The digestibility of soybean meal can be severely impacted by trypsin inhibitor (TI), one of the most abundant anti-nutritional factors present in soybean seeds. TI can restrain the function of trypsin, a critical enzyme that breaks down proteins in the digestive tract. Soybean accessions with low TI content have been identified. However, it is challenging to breed the low TI trait into elite cultivars due to a lack of molecular markers associated with low TI traits. We identified Kunitz trypsin inhibitor 1 (KTI1, Gm01g095000) and KTI3 (Gm08g341500) as two seed-specific TI genes. Mutant kti1 and kti3 alleles carrying small deletions or insertions within the gene open reading frames were created in the soybean cultivar Glycine max cv. Williams 82 (WM82) using the CRISPR/Cas9-mediated genome editing approach. The KTI content and TI activity both remarkably reduced in kti1/3 mutants compared to the WM82 seeds. There was no significant difference in terms of plant growth or maturity days of kti1/3 transgenic and WM82 plants in greenhouse condition. We further identified a T1 line, #5-26, that carried double homozygous kti1/3 mutant alleles, but not the Cas9 transgene. Based on the sequences of kti1/3 mutant alleles in #5-26, we developed markers to co-select for these mutant alleles by using a gel-electrophoresis-free method. The kti1/3 mutant soybean line and associated selection markers will assist in accelerating the introduction of low TI trait into elite soybean cultivars in the future.

Superior salt tolerance in wild soybean (G. soja) is associated with better ion ‘exclusion’ ability from leaves and mesophyll cells than cultivated soybean genotypes (G. max)

Soybean (Glycine max) is a salt-sensitive crop. However, wild soybean (Glycine soja) is a potential source of germplasm to improve salt tolerance in G. max. This study evaluated the response of cultivated soybean (G. max cv. Bunya and Lee) and wild soybean (G. soja) to ionic components of salt stress to test the hypothesis that wild and cultivated soybean genotypes differ in leaf tissue tolerance to Na+ and/or Cl–. The soybean genotypes were subjected to NaCl, Na+ salts, and Cl– salts at 50, 75 and 100 mM, and a non-saline control to analyse the effect of salts/ions on growth, tissue ion concentrations and photosynthesis. Cryo-SEM X-ray microanalysis was used to evaluate cellular [Na], [Cl] and [K] in various cell types within leaflets. NaCl and Na+ salts reduced shoot and root dry mass more than Cl– salts in the three genotypes. Soja maintained higher photosynthetic rates (84 % of control) than Lee (70 % of control) and Bunya (60 % of control) in the 75 mM treatments. Soja had lower [Na+] in leaves and mesophyll cells than Lee and Bunya. G. soja had greater tolerance to salinity than G. max due to better ‘ion exclusion’ from leaves and photosynthetically active mesophyll cells.

Development of a High Yielded Chlorsulfuron-Resistant Soybean (Glycine max L.) Variety through Mutation Breeding

This study was conducted to develop a novel herbicide resistance soybean using ethyl methanesulfonate (EMS) mutagen. In this study, 0.1% of EMS mutagen was applied to the soybean [Glycine max (L.) cv Arısoy] seeds. A single resistant mutant was selected in the M2 population evaluated under field and greenhouse conditions. The AHAS gene regions of the herbicide-resistant mutant progeny were mapped, and the nucleotide changes were defined conferring herbicide resistance. The sequence analysis of the AHAS gene indicated that three nucleotide substitutions were detected such as 407 (C/T), 532 (C/T), and 1790 (C/T). According to the AHAS gene protein sequence of Arabidopsis thaliana, Ala155Val, Pro197Ser, and Thr616Met amino acid alterations were found in the progeny of the resistant mutant. Pro197Ser alteration was common in all the progeny, while the others were diverse. The wild-type and the mutant plants were compared for seed yield, number of pods per plant, stem height to the first pod, 1000-seed weight, and physiological maturity days for two subsequent years. No statistical difference was found between the mutant and wild types with respect to seed yield and its components. The agronomic data indicated that EMS provided target-site resistance to sulfonylureas (SU) with no tradeoff between yield components and resistance.

RNA-seq Gene Profiling Reveals Transcriptional Changes in the Late Phase during Compatible Interaction between a Korean Soybean Cultivar (Glycine max cv. Kwangan) and Pseudomonas syringae pv. syringae B728a

Soybean (Glycine max (L) Merr.) provides plant-derived proteins, soy vegetable oils, and various beneficial metabolites to humans and livestock. The importance of soybean is highly underlined, especially when carbon-negative sustainable agriculture is noticeable. However, many diseases by pests and pathogens threaten sustainable soybean production. Therefore, understanding molecular interaction between diverse cultivated varieties and pathogens is essential to developing disease-resistant soybean plants. Here, we established a pathosystem of the Korean domestic cultivar Kwangan against Pseudomonas syringae pv. syringae B728a. This bacterial strain caused apparent disease symptoms and grew well in trifoliate leaves of soybean plants. To examine the disease susceptibility of the cultivar, we analyzed transcriptional changes in soybean leaves on day 5 after P. syringae pv. syringae B728a infection. About 8,900 and 7,780 differentially expressed genes (DEGs) were identified in this study, and significant proportions of DEGs were engaged in various primary and secondary metabolisms. On the other hand, soybean orthologs to well-known plant immune-related genes, especially in plant hormone signal transduction, mitogen-activated protein kinase signaling, and plant-pathogen interaction, were mainly reduced in transcript levels at 5 days post inoculation. These findings present the feature of the compatible interaction between cultivar Kwangan and P. syringae pv. syringae B728a, as a hemibiotroph, at the late infection phase. Collectively, we propose that P. syringae pv. syringae B728a successfully inhibits plant immune response in susceptible plants and deregulates host metabolic processes for their colonization and proliferation, whereas host plants employ diverse metabolites to protect themselves against infection with the hemibiotrophic pathogen at the late infection phase.

In Transition towards Organic Farming: Effects of Rock Phosphate, Coral Lime, and Green Manure on Soil Fertility of an Acid Oxisol and the Growth of Soybean (Glycine max L. Merr.) Seedlings

Maintaining soil fertility and obtaining good crop yields in highly weathered tropical soils through organic practices–without chemical/synthetic inputs—requires a scientific approach and skillful managements, especially for phosphorus (P) nutrient. Our objective was to find a combination of lime and rock phosphate additions that made soil pH low enough so that rock phosphate would be adequately soluble, yet high enough so soil acidity is not harmful to most crops. Thus, a controlled (greenhouse) experiment was conducted to quantify soil properties, and soybean (Glycine max cv. Kahala) growth when rock phosphate, coral lime, and cowpea (Vigna unguiculata) green manure were applied as organic amendments to an acid, nutrient poor Oxisol of Hawaii. The treatments were a factorial combination of 3 application rates (0, 1, 2 g/kg) of coral lime (86% CaCO3 equivalent) from Western Samoa, 3 rates (0, 75, 150 mg/kg total P) of rock phosphate (10.6% total P, and 3.7% citrate extractable P) from central Florida, and 3 rates (0, 5, 10 g/kg) of a local cowpea green manure (2.7% N, 2.8% K). Each treatment was replicated 3 times, yielding a total of 81 pots of 2 kg soil each. Soybean seedlings were grown as a test crop. Our results showed that a combination of 1 g/kg (2 tons/ha) of lime and 75 mg/kg (150 kg P/ha) of rock phosphate provided enough P for soybean growth and simultaneously alleviated soil acidity problems (the green manure was to supply adequate N and K to the crop). Corresponding soil parameters were: soil pH = 5.2, exchangeable (KCl-extractable) Al = 3.6 mg/kg, Olsen (NaHCO3- extractable) P = 11 mg/kg, and soil-solution P of 0.05 mg/L. Our results lent support to the sustainable potential of organic farming.

Soil Treatment with Nitric Oxide-Releasing Chitosan Nanoparticles Protects the Root System and Promotes the Growth of Soybean Plants under Copper Stress.

The nanoencapsulation of nitric oxide (NO) donors is an attractive technique to protect these molecules from rapid degradation, expanding, and enabling their use in agriculture. Here, we evaluated the effect of the soil application of chitosan nanoparticles containing S-nitroso-MSA (a S-nitrosothiol) on the protection of soybeans (Glycine max cv. BRS 257) against copper (Cu) stress. Soybeans were grown in a greenhouse in soil supplemented with 164 and 244 mg kg-1 Cu and treated with a free or nanoencapsulated NO donor at 1 mM, as well as with nanoparticles without NO. There were also soybean plants treated with distilled water and maintained in soil without Cu addition (control), and with Cu addition (water). The exogenous application of the nanoencapsulated and free S-nitroso-MSA improved the growth and promoted the maintenance of the photosynthetic activity in Cu-stressed plants. However, only the nanoencapsulated S-nitroso-MSA increased the bioavailability of NO in the roots, providing a more significant induction of the antioxidant activity, the attenuation of oxidative damage, and a greater capacity to mitigate the root nutritional imbalance triggered by Cu stress. The results suggest that the nanoencapsulation of the NO donors enables a more efficient delivery of NO for the protection of soybean plants under Cu stress.

Genetic and Physiological Characterization of Soybean-Nodule-Derived Isolates from Bangladeshi Soils Revealed Diverse Array of Bacteria with Potential Bradyrhizobia for Biofertilizers.

Genetic and physiological characterization of bacteria derived from nodules of leguminous plants in the exploration of biofertilizer is of paramount importance from agricultural and environmental perspectives. Phylogenetic analysis of the 16S rRNA gene of 84 isolates derived from Bangladeshi soils revealed an unpredictably diverse array of nodule-forming and endosymbiotic bacteria-mostly belonging to the genus Bradyrhizobium. A sequence analysis of the symbiotic genes (nifH and nodD1) revealed similarities with the 16S rRNA gene tree, with few discrepancies. A phylogenetic analysis of the partial rrn operon (16S-ITS-23S) and multi-locus sequence analysis of atpD, glnII, and gyrB identified that the Bradyrhizobium isolates belonged to Bradyrhizobium diazoefficiens, Bradyrhizobium elkanii, Bradyrhizobium liaoningense and Bradyrhizobium yuanmingense species. In the pot experiment, several isolates showed better activity than B. diazoefficiens USDA110, and the Bho-P2-B2-S1-51 isolate of B. liaoningense showed significantly higher acetylene reduction activity in both Glycine max cv. Enrei and Binasoybean-3 varieties and biomass production increased by 9% in the Binasoybean-3 variety. Tha-P2-B1-S1-68 isolate of B. diazoefficiens significantly enhanced shoot length and induced 10% biomass production in Binasoybean-3. These isolates grew at 1-4% NaCl concentration and pH 4.5-10 and survived at 45 °C, making the isolates potential candidates for eco-friendly soybean biofertilizers in salty and tropical regions.

Insight into the Mechanism of Salt-Induced Oxidative Stress Tolerance in Soybean by the Application of Bacillus subtilis: Coordinated Actions of Osmoregulation, Ion Homeostasis, Antioxidant Defense, and Methylglyoxal Detoxification.

Considering the growth-promoting potential and other regulatory roles of bacteria, we investigated the possible mechanism of the role of Bacillus subtilis in conferring salt tolerance in soybean. Soybean (Glycine max cv. BARI Soybean-5) seeds were inoculated with B. subtilis, either through a presoaking with seeds or a direct application with pot soil. After 20 days of sowing, both the seed- and soil-inoculated plants were exposed to 50, 100, and 150 mM of NaCl for 30 days. A clear sign of oxidative stress was evident through a remarkable increase in lipid peroxidation, hydrogen peroxide, methylglyoxal, and electrolyte leakage in the salt treated plants. Moreover, the efficiency of the ascorbate (AsA)–glutathione (GSH) pathways was declined. Consequently, the plant growth, biomass accumulation, water relations, and content of the photosynthetic pigments were decreased. Salt stress also caused an increased Na+/K+ ratio and decreased Ca2+. On the contrary, the B. subtilis inoculated plants showed increased levels of AsA and GSH, their redox balance, and the activities of the AsA–GSH pathway enzymes, superoxide dismutase, catalase, glutathione peroxidase, glutathione S-transferase, and peroxidase. The B. subtilis inoculated plants also enhanced the activities of glyoxalase enzymes, which mitigated methylglyoxal toxicity in coordination with ROS homeostasis. Besides this, the accumulation of K+ and Ca2+ was increased to maintain the ion homeostasis in the B. subtilis inoculated plants under salinity. Furthermore, the plant water status was uplifted in the salt treated soybean plants with B. subtilis inoculation. This investigation reveals the potential of B. subtilis in mitigating salt-induced oxidative stress in soybean plants through modulating the antioxidant defense and glyoxalase systems along with maintaining ion homeostasis and osmotic adjustments. In addition, it was evident that the soil inoculation performed better than the seed inoculation in mitigating salt-induced oxidative damages in soybean.

In vitro Bioassay of Allelopathic Activities of Soybean, and Three Isoflavones, Using Protoplast Co-culture Method with Digital Image Analysis

Inhibitory allelopathic activities of dried leaves of potted plants and protoplasts of Glycine max (soybean) cv. Okuhara-wase were studied using two in vitro bioassay methods. Strong inhibition (90%) of growth of recipient lettuce root was obtained with 50 mg soybean leaves using the lettuce seedling growth test (sandwich method), and moderate inhibition (65%) of lettuce protoplast division was obtained with 100 × 103 mL-1 protoplasts of etiolated soybean seedlings using the protoplast co-culture method with digital image analysis (DIA-PP method). Three isoflavones, genistein, genistin (genistein-7-O-glucoside), and daidzin (daidzein-7-O-glucoside) were investigated as putative allelochemicals using the DIA-PP method. The three isoflavones at 100 µM showed early crystal accumulation in lettuce protoplasts and inhibited lettuce protoplast division by 100%. Genistein showed the strongest inhibition. The results were compared and discussed with the previous reports on the invader leguminous plant, Kudzu, and two isoflavones, daidzein and Kudzu-specific puerarin (daidzein-6-C-glucoside), and other allelopathic plants and their putative allelochemicals.

Effector-triggered inhibition of nodulation: A rhizobial effector protease targets soybean kinase GmPBS1-1.

Type III protein secretion systems of nitrogen-fixing rhizobia deliver effector proteins into leguminous host cells to promote or inhibit the nodule symbiosis. However, mechanisms underlying effector-triggered inhibition of nodulation remain largely unknown. Nodulation outer protein T (NopT) of Sinorhizobium sp. NGR234 is an effector protease related to the Pseudomonas effector Avirulence protein Pseudomonas phaseolicola B (AvrPphB). Here, we constructed NGR234 mutants producing different NopT variants and found that protease activity of NopT negatively affects nodulation of smooth crotalaria (Crotalaria pallida). NopT variants lacking residues required for autocleavage and subsequent lipidation showed reduced symbiotic effects and were not targeted to the plasma membrane. We further noticed that Sinorhizobium fredii strains possess a mutated nopT gene. Sinorhizobium fredii USDA257 expressing nopT of NGR234 induced considerably fewer nodules in soybean (Glycine max) cv. Nenfeng 15 but not in other cultivars. Effector perception was further examined in NopT-expressing leaves of Arabidopsis (Arabidopsis thaliana) and found to be dependent on the protein kinase Arabidopsis AvrPphB Susceptible 1 (AtPBS1) and the associated resistance protein Arabidopsis Resistance to Pseudomonas syringae 5 (AtRPS5). Experiments with Nicotiana benthamiana plants indicated that the soybean homolog GmPBS1-1 associated with AtRPS5 can perceive NopT. Further analysis showed that NopT cleaves AtPBS1 and GmPBS1-1 and thus can activate these target proteins. Insertion of a DKM motif at the cleavage site of GmPBS1-1 resulted in increased proteolysis. Nodulation tests with soybeans expressing an autoactive GmPBS1-1 variant indicated that activation of a GmPBS1-1-mediated resistance pathway impairs nodule formation in cv. Nenfeng 15. Our findings suggest that legumes face an evolutionary dilemma of either developing effector-triggered immunity against pathogenic bacteria or establishing symbiosis with suboptimally adapted rhizobia producing pathogen-like effectors.

Exogenous salicylic acid and kinetin modulate reactive oxygen species metabolism and glyoxalase system to confer waterlogging stress tolerance in soybean (Glycine max L.)

We conducted this study to investigate the positive effects of foliar-applied salicylic acid (SA) and kinetin (KN) in improving waterlogging stress tolerance, by upregulating reactive oxygen species (ROS) metabolism and antioxidant defense including glyoxalase system in soybean (Glycine max cv. Sohag) grown under different levels of waterlogging. Waterlogging was imposed on plants at 15 days after sowing at four different durations viz. waterlogging for 0 days (W0), waterlogging for 3 days (W3), waterlogging for 6 days (W6), waterlogging for 9 days (W9), and plants were supplemented with exogenous SA (0.5 mM) and KN (0.1 mM). Waterlogging increased lipid peroxidation (malondialdehyde content), hydrogen peroxide content, leaf electrolyte leakage, proline content, and glutathione S-transferase (GST) activity while ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), catalase (CAT), glutathione peroxidase (GPX), peroxidase (POD), glyoxalase I (Gly I) and glyoxalase II (Gly II) activities were decreased. On the contrary, exogenous SA and KN reduced the MDA content, H2O2 content, proline content, and leaf electrolyte leakage under waterlogging. Further, supplementation of SA and KN enhanced the activity of APX, MDHAR, DHAR, GR, CAT, GST, GPX, POD, Gly I, and Gly II under waterlogging stress. In the current study, the results indicate that both exogenous SA and KN effectively improved the ROS metabolism and waterlogging stress tolerance in soybean by enhancing the antioxidant defense and upregulating the glyoxalase system.

English

Clinacanthus nutans is an economically important medicinal plant that can be found grown in many countries in the Asian region. Useful medicine properties such as anti-cancer, anti-bacteria, and anti-viral, backed by its high content of phytochemical compounds such vitexin, isovitexin, stigmasterol and lupeol has increased the demand for C. nutans in the market. Extensive work had been carried out on its content and pharmacological activity using fresh samples but limited studies for in vitro cultures of C. nutans. No genome size estimation has been done for C. nutans. Objective of this study was to analyse nuclear DNA content of C. nutans using flow cytometry. Preparation of different nuclei isolation buffer and stoichiometric DNA staining using propidium iodide was carried out. The genome size of C. nutans was estimated using Glycine max cv. Polanka as internal standard and its genome size was compared with in vitro plantlets of C. nutans. Flow cytometry analysis revealed that nuclear 2C DNA of C. nutans content is estimated at 1.75 ± 0.006 pg. Coefficient of variation in flow cytometric analysis was within the limit of 5% implying that the results were reliable with the Tris.MgCl2 being the best nuclei isolation buffer. No significant difference was observed from field grown and in vitro C. nutans. This finding will assist further in genome size evolution analysis of Clinacanthus spp. and to determine polyploids for increased active compounds and biomass. Key word: Flow cytometry; Nuclear DNA content, Clinacanthus nutans.

Characterization of cadmium-tolerant endophytic fungi isolated from soybean (Glycine max) and barley (Hordeum vulgare)

Cadmium stress disrupts plant-microbial interactions and reduces plant growth and development. In plants, the tolerance to stress can be increased by inoculation with endophytic microorganisms. The aim of this study was to investigate the distribution of endophytic fungi in various plant organs of barley and soybean and evaluate their Cd removal ability.Two hundred fifty-three fungal strains were isolated from various organs of barley (Hordeum vulgare cv Arna) and soybean (Glycine max cv Almaty). The colonization rate ranged from 13.6% to 57.3% and was significantly higher in the roots. Ten genera were identified: Fusarium, Penicillium, Aspergillus, Metarhizium, Beauveria, Trichoderma, Rhodotorula, Cryptococcus, Aureobasidium and Metschnikowia. Twenty-three fungal strains have a Cd tolerance index from 0.24 to 1.12. Five strains (Beauveria bassiana T7, Beauveria bassiana T15, Rhodotorula mucilaginosa MK1, Rhodotorula mucilaginosa RH2, Metschnikowia pulcherrima MP2) with the highest level of Cd tolerance have minimum inhibitory concentrations from 290 to 2400 μg/ml. These fungi were able to remove Cd up to 59%. The bioaccumulation capacity ranged from 2.3 to 11.9 mg/g.Selected fungal strains could be considered as biological agents for their potential application in the bioremediation of contaminated sites.

Ampelopsin Confers Endurance and Rehabilitation Mechanisms in Glycine max cv. Sowonkong under Multiple Abiotic Stresses.

The present investigation aims to perceive the effect of exogenous ampelopsin treatment on salinity and heavy metal damaged soybean seedlings (Glycine max L.) in terms of physiochemical and molecular responses. Screening of numerous ampelopsin concentrations (0, 0.1, 1, 5, 10 and 25 μM) on soybean seedling growth indicated that the 1 μM concentration displayed an increase in agronomic traits. The study also determined how ampelopsin application could recover salinity and heavy metal damaged plants. Soybean seedlings were irrigated with water, 1.5% NaCl or 3 mM chosen heavy metals for 12 days. Our results showed that the application of ampelopsin raised survival of the 45-day old salinity and heavy metal stressed soybean plants. The ampelopsin treated plants sustained high chlorophyll, protein, amino acid, fatty acid, salicylic acid, sugar, antioxidant activities and proline contents, and displayed low hydrogen peroxide, lipid metabolism, and abscisic acid contents under unfavorable status. A gene expression survey revealed that ampelopsin application led to the improved expression of GmNAC109, GmFDL19, GmFAD3, GmAPX, GmWRKY12, GmWRKY142, and GmSAP16 genes, and reduced the expression of the GmERF75 gene. This study suggests irrigation with ampelopsin can alleviate plant damage and improve plant yield under stress conditions, especially those including salinity and heavy metals.

Weed Suppression, Biomass and Nitrogen Accumulation in Mixed-Species and Single-Species Cover Crops in a Tropical Sugarcane Fallow

While mixed-species cover crops are gaining worldwide popularity, their utility in the ‘plough-out’ period in tropical sugar cane systems has not been investigated. Field trials investigating weed suppression (one season only), biomass production and nitrogen accumulation of single-species and mixed-species cover crops were conducted over two seasons on a commercial sugarcane farm in the Australian tropics. Mixed-species cover crops showed strong weed suppression, and were among the top treatments for biomass production each year, but did not yield the highest biomass in either season. Sunn hemp (Crotalaria juncea cv. Global sunn) produced the most biomass in the drier-than-average 2016–2017 season (>10 t dry matter ha−1), while soybean (Glycine max cv. Leichardt) produced the most biomass (5.3 t dry matter ha−1) in the wetter-than-average 2018–2019 season, highlighting the influence of seasonal conditions on species’ biomass production. The inclusion of multiple species in a short-term cover crop in the tropics where extreme weather events can occur can thus be seen as a risk mitigation strategy given the risk of failure of any given species in a given season.

Extraction of Damba Black Soybean Gene by Means of Magnetic Nanoparticles and Investigation of Aluminum Tolerance

The aluminum tolerance of Tamba black soybean (Glycine max cv. Tamba) is closely related to organic acid secretion mechanisms. The gene responsible for this tolerance in this variety (GmFER84) is extracted from lysates of soybean root tips using silylated Fe3O4 nanomagnetic beads. GmFER84 (Glycine max XP 003540203.1) is a stable protein. Tobacco genetically transformed with GmFER84 using an Agrobacterium-mediated transformation was tested for aluminum tolerance. Citrate synthase and citric acid secretion in the roots of transgenic tobacco prove to be significantly higher than those of wild tobacco, and the antioxidant properties of transgenic tobacco are also substantially increased. Research on GmFER84 may enable further agronomic development.

Assessing the Plant Growth Promoting and Arsenic Tolerance Potential of Bradyrhizobium japonicum CB1809.

Accumulation of heavy metals in soil is of concern to the agricultural production sector, because of the potential threat to food quality and quantity. Inoculation with plant growth-promoting bacteria (PGPR) has previously been shown to alleviate heavy metal stress but the mechanisms are unclear. Potential mechanisms by which inoculation with Bradyrhizobium japonicum CB1809 affected the legume soybean (Glycine max cv. Zeus) and the non-legume sunflower (Helianthus annus cv. Hyoleic 41) were investigated in solution culture under 5 μM As stress. Adding As resulted in As tissue concentrations of up to 5 mg kg-1 (shoots) and 250 mg kg-1 (roots) in both species but did not reduce shoot or root biomass. Inoculation increased root biomass but only in the legume (soybean) and only with As. Inoculation resulted in large (up to 100%) increases in siderophore concentration but relatively small changes (±10-15%) in auxin concentration in the rhizosphere. However, the increase in siderophore concentration in the rhizosphere did not result in the expected increases in tissue N or Fe, especially in soybean, suggesting that their function was different. In conclusion, siderophores and auxins may be some of the mechanisms by which both soybean and sunflower maintained plant growth in As-contaminated media.

Effect of Drought Stress, Mycorrhiza and Bacteria on Mother Plant on Produced Seed Vigor and its Related Traits in Soybean (Glycine max cv. Kosar)

Effect of Drought Stress, Mycorrhiza and Bacteria on Mother Plant on Produced Seed Vigor and its Related Traits in Soybean (Glycine max cv. Kosar)

Nuclear Genome Size Determination Of Christia Vespertilionis Via Flow Cytometry

Abstract Christia vespertilionis (butterfly wing plant) is an ornamental plant originated from South East Asia with reported usage in traditional medicine practice and potential as an anticancer and antitumor. This research aims to estimate the genome size of C. vespertilionis via flow cytometry (FCM) method. The research was conducted with the optimisation of nuclear suspension preparation followed by the genome size estimation. Two chopping techniques [manual chopping (MC) and BDTM Medimachine (MM)] and two lysis buffers (Otto and LBO1) were tested. Otto buffer with manual chopping was found to be the most suitable method, generated fine DNA peak with minimum debris background, and coefficient of variation (CV) value less than 3%. Five replicates of the FCM analysis were made for the genome size determination. The estimated genome size of C. vespertilionis was found to be 3.22 pg by using Glycine max cv. Polanka (2C=2.5pg) as an external reference standard. Further comparison with other Christia species was not possible due to the lack of data on genome size. The genome size data of C. vespertilionis can be useful for future morphology and genetics studies of Christia species.