Photosynthesis In Soybean Research Articles

Photosynthetic characteristics and genetic mapping of a yellow-green leaf mutant jym165 in soybean

BackgroundLeaves are important sites for photosynthesis and can convert inorganic substances into organic matter. Photosynthetic performance is an important factor affecting crop yield. Leaf colour is closely related to photosynthesis, and leaf colour mutants are considered an ideal material for studying photosynthesis.ResultsWe obtained a yellow-green leaf mutant jym165, using ethyl methane sulfonate (EMS) mutagenesis. Physiological and biochemical analyses indicated that the contents of chlorophyll a, chlorophyll b, carotenoids, and total chlorophyll in the jym165 mutant decreased significantly compared with those in Jiyu47 (JY47). The abnormal chloroplast development of jym165 led to a decrease in net photosynthetic rate and starch content compared with that of JY47. However, quality traits analysis showed that the sum of oil and protein contents in jym165 was higher than that in JY47. In addition, the regional yield (seed spacing: 5 cm) of jym165 increased by 2.42% compared with that of JY47 under high planting density. Comparative transcriptome analysis showed that the yellow-green leaf phenotype was closely related to photosynthesis and starch and sugar metabolism pathways. Genetic analysis suggests that the yellow-green leaf phenotype is controlled by a single recessive nuclear gene. Using Mutmap sequencing, the candidate regions related of leaf colour was narrowed to 3.44 Mb on Chr 10.ConclusionsAbnormal chloroplast development in yellow-green mutants leads to a decrease in the photosynthetic pigment content and net photosynthetic rate, which affects the soybean photosynthesis pathway and starch and sugar metabolism pathways. Moreover, it has the potentiality to increase soybean yield under dense planting conditions. This study provides a useful reference for studying the molecular mechanisms underlying photosynthesis in soybean.

Short-term reoxygenation is not enough for the recovery of soybean plants exposed to saline waterlogging

The ability of plants to recover after stressful events is crucial for resuming growth and development and is a key trait when studying stress tolerance. However, there is a lack of information on the physiological responses and the time required to restore homeostasis after the stress experience. This study aimed to (i) enhance understanding of soybean photosynthesis performance during saline waterlogging and (ii) investigate the effects of this combined stress during the reoxygenation and recovery period. Soybean plants (cultivar PELBR10-6049 RR) were subjected to waterlogging, NaCl, or hypoxia + NaCl for 3 and 6 days. Afterward, plants were drained and allowed to recover for an additional two (short-term) and seven days (long-term). Compared to plants exposed to single stress, the combined hypoxia + NaCl treatment resulted in a lower net CO2 assimilation rate, ФPSII, and levels of photosynthetic pigments during the waterlogging period. Furthermore, hypoxia + NaCl increased foliar electrolyte leakage during waterlogging. In response to short-term reoxygenation, these negative effects were amplified, while prolonged reoxygenation resulted in a slight increase in biomass accumulation. In conclusion, full recovery was not achieved under any condition during the reoxygenation periods tested. Notably, the brief reoxygenation phase imposed greater stress than the initial stress conditions for plants facing combined stress. Although extended recovery increased biomass accumulation, it remained lower in plants previously subjected to saline waterlogging.

Elevated CO2 concentration enhances plant growth, photosynthesis, and ion homeostasis of soybean under salt-alkaline stress

Salt-alkaline stress adversely affects growth and productivity of soybean. In the event of global climate change, the effects of elevated CO2 concentration (eCO2) and salt-alkaline stress on soybean remain unclear. This study investigated the combined effects of elevated CO2 concentration (700 μmol·moL−1) and salt-alkaline stress on soybean growth, gas exchange, pigments profiles, antioxidative enzyme activities, osmolyte accumulation, Na+ and K+ contents, and genes involved in ion homeostasis. This study suggested that eCO2 improved plant physiological performance due to the greater net photosynthetic rate (+212.49 %) and water use efficiency (+92.86 %). Both salt-alkaline stress and eCO2 significantly increased catalase (CAT) activity in leaves and stems, significantly increased superoxide dismutase (SOD) activity in stems, and significantly increased peroxidase (POD) activity in whole plants of soybean. eCO2 significantly inhibited Na+ absorption as indicated by decreased Na+ contents in whole plants under salt-alkaline stress accompanied by lower relative electrical conductivity, thus reducing osmotic and ionic stress. eCO2 induced enhancement of expressions of gene encoding the ion transporter of GmHKT1;2, GmHKT1;5, GmHKT1;6, GmNHX5, and GmSOS1 in stems mediated Na+ and K+ transport, thus benefiting to keep ions homeostasis. These results suggest that eCO2 contributes to enhancing soybean tolerance to saline-alkaline stress.

Non-CG DNA hypomethylation promotes photosynthesis and nitrogen fixation in soybean

Non-CG DNA methylation, a plant-specific epigenetic mark mainly regulated by chromomethylase (CMT), is known to play important roles in Arabidopsis thaliana. However, whether and to what extent non-CG DNA methylation modulates agronomic traits in crops remain to be explored. Here, we describe the consequences of non-CG DNA hypomethylation on development, seed composition, and yield in soybean (Glycine max). We created a Gmcmt mutant line lacking function of all four CMT genes. This line exhibited substantial hypomethylation of non-CG (CHG and CHH) sites. Non-CG hypomethylation enhanced chromatin accessibility and promoted or repressed the expression of hundreds of functionally relevant genes, including upregulation of GOLDEN-LIKE 10 (GmGLK10), which led to enhanced photosynthesis and, unexpectedly, improved nitrogen fixation efficiency. The Gmcmt line produced larger seeds with increased protein content. This study provides insights into the mechanisms of non-CG methylation-based epigenetic regulation of soybean development and suggests viable epigenetic strategies for improving soybean yield and nutritional value.

Cyclic Electron Flow Alleviates the Stress of Light Fluctuation on Soybean Photosynthesis

Crops often face light intensity fluctuations in natural settings. Intercropping is widely used to improve crop yield and resource utilization worldwide, but crops suffer from high-frequency and high-intensity light fluctuations due to mutual crop influence. Soybean is an important legume crop and is often intercropped with other crops, but little is known about soybean’s response to light fluctuation environments. Herein, three fluctuation frequencies (1, 10, and 20 min/cycle) were used to analyze soybean photosynthesis responses by measuring leaf growth, chlorophyll content, gas exchange, and electron transfer. Our data revealed that faster fluctuation frequencies led to the stronger suppression of soybean morphology and photosynthesis, with significant reductions of 31.31% and 21.58%, respectively. Damage to photosystems II (PSII) and I (PSI) also intensified, with significant decreases of 18.52% and 18.38% in their effective quantum yields Y(II) and Y(I). Additionally, increased fluctuation frequency exacerbated the consumption of the plastoquinone pool and linear electron flow but enhanced the cyclic electron flow across the thylakoid membrane and, thus, increased heat dissipation in PSII. Our findings indicate that an increased fluctuation frequency inflicted more severe damage on the soybean photosynthesis system. However, PSI-enhanced CEF improved NPQ and coordinated photoprotection to some extent.

Genetic dissection of ten photosynthesis-related traits based on InDel- and SNP-GWAS in soybean.

A total of 416 InDels and 112 SNPs were significantly associated with soybean photosynthesis-related traits. GmIWS1 and GmCDC48 might be related to chlorophyll fluorescence and gas-exchange parameters, respectively. Photosynthesis is one of the main factors determining crop yield. A better understanding of the genetic architecture for photosynthesis is of great significance for soybean yield improvement. Our previous studies identified 5,410,112 single nucleotide polymorphisms (SNPs) from the resequencing data of 219 natural soybean accessions. Here, we identified 634,106 insertions and deletions (InDels) from these 219 accessions and used these InDel variations to perform principal component and linkage disequilibrium analysis of this population. The genome-wide association study (GWAS) were conducted on six chlorophyll fluorescence parameters (chlorophyll content, light energy absorbed per reaction center, quantum yield for electron transport, probability that a trapped exciton moves an electron into the electron transport chain beyond primary quinone acceptor, maximum quantum yield of photosystem II primary photochemistry in the dark-adapted state, performance index on absorption basis) and four gas-exchange parameters (intercellular carbon dioxide concentration, stomatal conductance, net photosynthesis rate, transpiration rate) and revealed 416 significant InDels and 112 significant SNPs. Based on GWAS results, GmIWS1 (encoding a transcription elongation factor) and GmCDC48 (encoding a cell division cycle protein) with the highest expression in the mapping region were determined as the candidate genes responsible for chlorophyll fluorescence and gas-exchange parameters, respectively. Further identification of favorable haplotypes with higher photosynthesis, seed weight and seed yield were carried out for GmIWS1 and GmCDC48. Overall, this study revealed the natural variations and candidate genes underlying the photosynthesis-related traits based on abundant phenotypic and genetic data, providing valuable insights into the genetic mechanisms controlling photosynthesis and yield in soybean.

Long term co-application of biochar and fertilizer could increase soybean yield under continuous cropping: insights from photosynthetic physiology.

Photosynthesis is the key to crop yield. The effect of biochar on photosynthetic physiology and soybean yield under continuous cropping is unclear. We conducted a long-term field experiment to investigate the effects of co-application of biochar and fertilizer (BCAF) on these parameters. Five treatments were established: F2 (fertilizer), B1F1 (3 t hm-2 biochar plus fertilizer), B1F2 (3 t hm-2 biochar plus reduced fertilizer), B2F1 (6 t hm-2 biochar plus fertilizer), and B2F2 (6 t hm-2 biochar plus reduced fertilizer). BCAF increased chlorophyll and leaf area, enhancing soybean photosynthesis. The net photosynthetic rate (Pn ), transpiration rate (Tr ), stomatal conductance (Gs ), water use efficiency (WUE) and intercellular carbon dioxide (CO2 ) concentration (Ci ) were enhanced by BCAF. In addition, BCAF improved soybean photosystem II (PSII) photosynthetic performance, driving force, potential photochemical efficiency (Fv /F0 ), and quantum yield of electron transfer (φE0 ). Furthermore, BCAF enhanced the accumulation of photosynthetic products, such as soluble proteins, soluble sugars and sucrose content, resulting in higher leaf dry weight. Consequently, BCAF increased the soybean yield, with the highest increase of 41.54% in B2F1. The correlation analysis revealed positive relationships between soybean yield and chlorophyll, leaf area, maximal quantum yield of PSII (Fv /Fm ), electron transport flux per cross-section at t = 0 (ET0 /CS0 ), trapped energy flux per cross-section at t = 0 (TR0 /CS0 ), composite blade driving force (DFTotal ), and leaf dry weight. We demonstrated that long-term BCAF enhances soybean photosynthesis under continuous planting, reduces fertilizer use and increases yield. This study reveals a novel way and theory to sustainably increase soybean productivity. © 2023 Society of Chemical Industry.

Effect of Metal Nanoparticles on Photosynthetic and Antioxidant Enzyme Activities of Soybean

This study presents the effects of nanoscale zerovalent cobalt (NZVC) on the photosynthetic activity and expression of genes related to the photosynthetic apparatus as well as the activity of antioxidant enzymes in soybean (Glycine max L. Merr). Treatment of soybean seeds with NZVC solution (at concentrations of 0.17; 0.33 and 100 mg/kg seed) has increased the efficiency of light energy absorbed by photosystem II, improved photosynthetic efficiency, and maintained the function of photosynthetic apparatus when plant growth is reduced by enhancing the value of photosynthetic parameters (Fo, Fm, Fv/Fm, ETR, FPSII) compared with the control. The expression of genes involved in photosynthesis in soybean leaves was changed by growth time and NZVC treatment concentration. The psaA, Lhca, psbA, and psbB genes had increased expression levels at 17 and 32 days after sowing, then decreased at 70 days after sowing. The expression of the psbE, and Cyt b6f genes was greater than the control during the growth period. Treatment of soybean seeds with high concentrations of NZVC (0.33 and 100 mg/kg seed) did not negatively affect the photosynthetic function of soybean plants. The activity of nitrate and nitrite reductases and antioxidant enzymes including superoxide dismutase, catalase, peroxidase, and ascorbate peroxidase of cobalt-treated plants were better than those of the control. This is a defense mechanism of plants to minimize the harmful effects of these stresses. This result has elucidated the mechanism of increasing the yield of soybean when its seeds were treated with NZVC.

Selenium nanomaterials promoted ferredoxin and iron–sulfur protein synthesis and acetyl CoA carboxylase activity to improve the photosynthesis and fatty-acid synthesis in soybean

Herein, the effect of selenium engineered nanomaterials (Se ENMs) on soybean photosynthesis and fatty-acid synthesis by regulating ferredoxin (Fd) and iron–sulfur (Fe/S) protein synthesis and acetyl CoA carboxylase (ACC) activity was explored.

The interactive effect of high temperature and water deficit stress on nitrogen fixation, photosynthesis, chlorophyll fluorescence, seed yield and quality in soybean (Glycine max)

The interactive effect of high temperature and water deficit stress on nitrogen fixation, photosynthesis, chlorophyll fluorescence, seed yield and quality in soybean (Glycine max)

Jasmonic acid priming augments antioxidant defense and photosynthesis in soybean to alleviate combined heat and drought stress effects

In the aftermaths of global warming, plants are more frequently exposed to the combination of heat stress and drought in natural conditions. Jasmonic acid (JA) has been known to modulate numerous plant adaptive responses to diverse environmental stresses. However, the function of JA in regulating plant responses to the combined effects of heat and drought remains underexplored. In this study, we elucidated the functions of JA in enhancing the combined heat and drought tolerance of soybean (Glycine max). Our results showed that priming with JA improved plant biomass, photosynthetic efficiency and leaf relative water content, which all together contributed to the improved performance of soybean plants under single and combined heat and drought conditions. Exposure to single and combined heat and drought conditions caused oxidative damage in soybean leaves. Priming soybean plants, which were exposed to single and combined heat and drought conditions, with JA, on the other hand, substantially quenched the reactive oxygen species-induced oxidative burden possibly by bolstering their antioxidant defense system. Together, our findings provide direct evidence of the JA-mediated protective mechanisms in maintaining the optimal photosynthetic rate and plant performance under combined heat and drought conditions.

Effect of Pesticides and a Long-Life Inoculant on Nodulation Process and Soybean Seed Quality during Storage

Inoculants containing strains of bacteria that fix atmospheric N that are tolerant or resistant to chemical products commonly used in seed treatment are classified as long-life inoculants, which contribute to improving the efficiency of nodulating bacteria in soybean crops. The objective of this work was to evaluate the effects of applying commonly used pesticides in seed treatment and a long-life inoculant, alone or in combination, on the nodulation process and seed quality of soybeans during storage. The first experiment was carried out in a greenhouse using a completely randomized design, in an 8 × 2 factorial arrangement, with three replications. The treatments consisted of applications of industrial seed treatments: control, MaximAdvanced, Fortenza, long-life inoculant, MaximAdvanced + Fortenza, MaximAdvanced + long-life inoculant, Fortenza + long-life inoculant, and MaximAdvanced + Fortenza + long-life inoculant. The seeds were sown in pots containing soils from two crop areas. The second experiment was carried out in a laboratory, using a completely randomized design in an 8 × 7 factorial arrangement, with four replications. The treatments consisted of the same eight treatments used in the greenhouse experiment, which were applied before packaging and storing the seeds for two months. The industrial seed treatment with the mixture of fungicide, insecticide, and inoculants improved the soybean photosynthesis and nodulation processes, regardless of the history of the area. Soybean seeds can be stored for commercial purposes for up to 40 days, regardless of the seed treatment with fungicide, insecticide, and long-life inoculant applied alone or in combination.

Photosynthetic Acclimation of Shade-Grown Soybean Seedlings to a High-Light Environment.

Soybean in relay intercropping is initially exposed to a shade environment, followed by exposure to full sunlight after the harvesting of primary crops, e.g., maize. Therefore, soybean's ability to acclimate to this changing light environment determines its growth and yield formation. However, the changes in soybean photosynthesis under such light alternations in relay intercropping are poorly understood. This study compared the photosynthetic acclimation of two soybean varieties with contrasting shade tolerance, i.e., Gongxuan1 (shade-tolerant) and C103 (shade-intolerant). The two soybean genotypes were grown in a greenhouse under full sunlight (HL) and 40% full sunlight (LL) conditions. Subsequently, after the fifth compound leaf expanded, half of the LL plants were transferred to a high-sunlight environment (LL-HL). Morphological traits were measured at 0 and 10 days, while chlorophyll content, gas exchange characteristics and chlorophyll fluorescence were assayed at 0, 2, 4, 7 and 10 days after transfer to an HL environment (LL-HL). Shade-intolerant C103 showed photoinhibition 10 days after transfer, and the net photosynthetic rate (Pn) did not completely recover to that under a high light level. On the day of transfer, the shade-intolerant variety, C103, exhibited a decrease in net photosynthetic rate (Pn), stomatal conductance (Gs) and transpiration rate (E) in the low-light (LL) and low-light-to-high-light (LL-HL) treatments. Additionally, intercellular CO2 concentration (Ci) increased in low light, suggesting that non-stomatal factors were the primary limitations to photosynthesis in C103 following the transfer. In contrast, the shade-tolerant variety, Gongxuan1, displayed a greater increase in Pn 7 days after transfer, with no difference observed between the HL and LL-HL treatments. Ten days after transfer, the shade-tolerant Gongxuan1 exhibited 24.1%, 10.9% and 20.9% higher biomass, leaf area and stem diameter than the intolerant C103. These findings suggest that Gongxuan1 possesses a higher capacity to adapt to variations in light conditions, making it a potential candidate for variety selection in intercropping systems.

Physiology and proteomics analyses reveal the regulatory mechanism of mepiquat chloride in soybean

Soybean is an important grain and oil crop cultivated worldwide. Mepiquat chloride (DPC), a plant growth regulator, is widely used in cotton planting; however, its application in soybean remains rarely studied. Herein, we explored DPC regulation in soybeans using morphology, physiology, and proteomics analyses. Morphological and physiological analyses showed that DPC significantly reduced the plant height and shoot dry weight, promoted the growth of lateral roots in a specific concentration range, increased the activities of the leaf protective enzymes (superoxide dismutase and catalase), and decreased and increased malondialdehyde and total flavonoid contents, respectively. Proteomic analysis of leaves treated with 100 mg/L DPC revealed that multiple proteins related to plant growth and stress resistance were regulated after treatment. The key proteins involved in photosynthesis and cell wall elongation in the two varieties of soybean were significantly downregulated and those related to promoting lateral root growth and stress resistance were significantly upregulated. Overall, DPC inhibited shoot growth and photosynthesis in soybean but promoted lateral root growth, enhanced protective enzyme activity, and improved the ability of plants to resist abiotic stress. This study preliminarily determined the suitable DPC concentration for soybean spraying and provided a theoretical basis for its rational application.

Transcriptome analysis of soybean roots in response to boron deficiency

Boron (B) deficiency is detrimental to Glycine max (L.) Merr., which is one of the leading oil crops. In this study, physiological analysis of soybean seedlings under B deficiency and control after 12 h, 24 h, 72 h and 8 days was carried out, and the roots were subjected to transcriptome sequencing analysis. The results showed that under B deficiency, the plant height, SPAD and chlorophyll fluorescence value of soybean seedlings decreased significantly, indicating that B stress significantly inhibited plant growth and photosynthesis. RNA-seq revealed a total of 5126 DEGs (Differentially Expressed Genes), and nine DEGs co-existed at the four-time points, among which GLYMA_03G130600 regulates transcription factor ORG3, which is related to plant growth. GO analysis revealed a total of annotated 4018 DEGs, among which the terms plasma membrane, extracellular, enzyme activity, ion transport metabolic process and oxidoreductase activity were significantly enriched at the four time points, which might hinder the growth of soybean and accelerate senescence. KEGG analysis showed that at level 1, the DEGs were mainly enriched in photosynthesis-related, phenylpropanoid biosynthesis, nitrogen metabolism and plant hormone signal transduction. At level 2 of secondary metabolism, the DEGs were mainly enriched in energy metabolism and amino acid metabolism pathways, which indicates that B stresses mainly affect photosynthesis, hormone regulation and amino acid metabolism of soybean, thus affecting plant growth. The above results give deeper insight into the soybean response to B deficiency and lay the foundation for further studies of the molecular mechanism of soybean response to boron deficiency.

Comment on "Soybean photosynthesis and crop yield are improved by accelerating recovery from photoprotection".

De Souza et al. (Research Articles, 19 Aug 2022, adc9831) recently claimed major soybean yield increases resulting from transformation of the nonphotochemical quenching mechanism of photosynthesis. However, there is little basis for the premise that such a transformation would result in yield increase. The field experiment was flawed and does not provide evidence for increases in crop yield.

Response to Comments on "Soybean photosynthesis and crop yield is improved by accelerating recovery from photoprotection".

We recently demonstrated that accelerating the relaxation of nonphotochemical quenching leads to higher soybean photosynthetic efficiency and yield. In response, Sinclair et al. assert that improved photosynthesis cannot improve crop yields and that there is only one valid experimental design for proving a genetic improvement in yield. We explain here why neither assertion is valid.

GmFtsH25 overexpression increases soybean seed yield by enhancing photosynthesis and photosynthates.

Increasing plant photosynthetic capacity is a promising approach to boost yields, but it is particularly challenging in C3 crops, such as soybean (Glycine max (L.) Merr.). Here, we identified GmFtsH25, encoding a member of the filamentation temperature-sensitive protein H protease family, as a major gene involved in soybean photosynthesis, using linkage mapping and a genome-wide association study. Overexpressing GmFtsH25 resulted in more grana thylakoid stacks in chloroplasts and increased photosynthetic efficiency and starch content, while knocking out GmFtsH25 produced the opposite phenotypes. GmFtsH25 interacted with photosystem I light harvesting complex 2 (GmLHCa2), and this interaction may contribute to the observed enhanced photosynthesis. GmFtsH25 overexpression lines had superior yield traits, such as yield per plant, compared to the wild type and knockout lines. Additionally, we identified an elite haplotype of GmFtsH25, generated by natural mutations, which appears to have been selected during soybean domestication. Our study sheds light on the molecular mechanism by which GmFtsH25 modulates photosynthesis and provides a promising strategy for improving the yields of soybean and other crops.

Cloning and functional study of GmRPI2, which is the critical gene of photosynthesis in soybean.

Light provides energy for photosynthesis and is also an important environmental signal that regulates plant growth and development. Ribose-5-phosphate isomerase plays a crucial role in photosynthesis. However, ribose-5-phosphate isomerase has yet to be studied in soybean photosynthesis. To understand the biological function of GmRPI2, in this study, GmRPI2 was cloned, plant overexpression vectors and gene editing vectors were successfully constructed, and transformed into recipient soybean JN74 using the Agrobacterium-mediated method. Using qRT-PCR, we analyzed that GmRPI2 gene expression was highest in leaves, second highest in roots, and lowest in stems. Promoter analysis revealed the presence of multiple cis-acting elements related to light response in the promoter region of GmRPI2. Compared with the control soybean plants, the net photosynthetic rate and transpiration rate of the overexpression lines were higher than those of the control and gene editing lines, while the intercellular CO2 concentration was significantly lower than that of the control and gene editing lines; the total chlorophyll, chlorophyll a, chlorophyll b contents and soluble sugar contents of the overexpression plants were significantly higher than those of the recipient and editing plants, indicating that the GmRPI2 gene can increase The GmRPI2 gene can increase the photosynthetic capacity of soybean plants, providing a theoretical basis and genetic resources for improving soybean yield by regulating photosynthetic efficiency.

The Impact of Polymer on the Productivity and Photosynthesis of Soybean under Different Water Levels

In order to practice sustainable and resource-efficient agriculture, the use of new technologies such as water-retaining polymers is essential. The objective of this study was to evaluate the effect of a polymer incorporated into the soil on gas exchange and yield under different water regimes (WR) in three soybean cultivars. The experiment was conducted at Embrapa Cerrados under field conditions in 2016 and 2017, using three different cultivars (BRS 5980IPRO, NA 5909RG and BRS 7280RR). Soybean cultivars were submitted to four water regimes (representing 30%, 50%, 83% and 100% of evapotranspiration replacement, namely WR1, WR2, WR3 and WR4). No beneficial results were observed in 2016 with Polymer. Most of the reductions in photosynthesis and transpiration by adding the polymer can be attributed to stomatal control, but such reductions did not influence productivity. In 2017, the yield was higher using Polymer in WR4 and WR3 by 40 to 20%, depending on the cultivar. Under severe stress (WR2 and WR1), reduced gas exchange was obtained with Polymer, but the yield was not reduced. These results indicate that Polymer contributed to the prolongation of photosynthetic activity during the reproductive phase of soybean and may represent a potential strategy for increasing yield under moderate drought stress.