Rhizobia are nitrogen-fixing bacteria that establish a nodule symbiosis with legumes. Nodule formation depends on signals and surface determinants produced by both symbiotic partners. Among them, ...rhizobial Nops (nodulation outer proteins) play a crucial symbiotic role in many strain-host combinations. Nops are defined as proteins secreted via a rhizobial T3SS (type III secretion system). Functional T3SSs have been characterized in many rhizobial strains. Nops have been identified using various genetic, biochemical, proteomic, genomic and experimental approaches. Certain Nops represent extracellular components of the T3SS, which are visible in electron micrographs as bacterial surface appendages called T3 (type III) pili. Other Nops are T3 effector proteins that can be translocated into plant cells. Rhizobial T3 effectors manipulate cellular processes in host cells to suppress plant defence responses against rhizobia and to promote symbiosis-related processes. Accordingly, mutant strains deficient in synthesis or secretion of T3 effectors show reduced symbiotic properties on certain host plants. On the other hand, direct or indirect recognition of T3 effectors by plant cells expressing specific R (resistance) proteins can result in effector triggered defence responses that negatively affect rhizobial infection. Hence Nops are double-edged swords that may promote establishment of symbiosis with one legume (symbiotic factors) and impair symbiotic processes when bacteria are inoculated on another legume species (asymbiotic factors). In the present review, we provide an overview of our current understanding of Nops. We summarize their symbiotic effects, their biochemical properties and their possible modes of action. Finally, we discuss future perspectives in the field of T3 effector research.
This essay follows a somewhat unconventional approach to writing about Indian dance in the diaspora. I say “unconventional” because it unfolds as a kind of self-reflexive narration of my own journey ...as a “doubly diasporic” Indian dancer, born in Singapore but having made my career in North America. In essence, I map my own unconventional paths to understanding Indian dance in the diaspora, outside the tired and troublesome idea of “dance as heritage”. The aim of this critical meditation on my own work is to offer up new possibilities for moving Indian dance into progressive conceptual spaces that direct it out of the discursive field of cultural nationalism that frames the idea of “heritage”.
Mutagenesis through fast neutron (FN) radiation of soybean resulted in a mutant with a 15% increase in seed protein content. A comparative genomic hybridization analysis confirmed that the mutant is ...lacking 24 genes located at chromosomes 5 and 10. A tandem mass tag-based proteomic profiling of the wild type and the FN mutant revealed 3,502 proteins, of which 206 proteins exhibited increased abundance and 214 proteins showed decreased abundance. Among the abundant proteins, basic 7S globulin increased fourfold, followed by vacuolar-sorting receptor and protein transporters. The differentially expressed proteins were mapped on the global metabolic pathways. It was observed that there was an enrichment of 29 ribosomal proteins, 16 endoplasmic reticular proteins, and several proteins in export metabolic pathways. The deletion of the sequence-specific DNA binding transcription factor along with 23 other genes may have altered the negative regulation of protein syntheses processes, resulting in an increase in the overall protein content of the mutant seed. This mutant is a valuable resource for researchers to understand the metabolic pathways that may affect an increase in seed protein content (the mass spectrometry data files were submitted to massive.ucsd.edu # MassIVE MSV000084228).
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Using high throughput tandem mass tag (TMT) based tagging technique, we identified 4172 proteins in three developmental stages: early, mid, and late seed filling. We mapped the identified proteins to ...metabolic pathways associated with seed filling. The elevated abundance of several kinases was observed from the early to mid‐stages of seed filling, indicating that protein phosphorylation was a significant event during this period. The early to late seed filling stages were characterized by an increased abundance of proteins associated with the cell wall, oil, and vacuolar‐related processes. Among the seed storage proteins, 7S (β‐subunit) and 11S (Gy3, Gy4, Gy5) steadily increased in abundance during early to late stages of seed filling, whereas 2S albumin exhibited a decrease in abundance during the same period. An increased abundance of proteases, senescence‐associated proteins, and oil synthesis proteins was observed from the mid to late seed filling stages. The mid to late stages of seed filling was also characterized by a lower abundance of transferases, transporters, Kunitz family trypsin, and protease inhibitors. Two enzymes associated with methionine synthesis exhibited lower abundance from early to late stages. This study unveiled several essential enzymes/proteins related to amino acid and protein synthesis and their accumulation during seed development. All data can be accessed through this link: https://massive.ucsd.edu/ProteoSAFe/dataset.jsp?task=38784ecbd0854bb3801afc0d89056f84. (Accession MSV000087577)
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Soybean meal is considered as “gold standard” to which other protein sources are compared.•The nutritional value of soybean could be improved by enhancing the content of cysteine and ...methionine.•There is limitation in the availability of cysteine and methionine in legume seeds.•Manipulation of enzymes involved in the sulfur assimilatory pathway appears to be a viable avenue for improving sulfur amino acid content.
Soybeans are an excellent source of protein in monogastric diets and rations with ∼75% of soybeans produced worldwide used primarily for animal feed. Even though soybeans are protein-rich and have a well-balanced amino acid profile, the nutritive quality of this important crop could be further improved by elevating the concentrations of certain amino acids. The levels of the sulfur-containing amino acids cysteine and methionine in soybean seed proteins are inadequate for optimal growth and development of monogastric animals, which necessitates dietary supplementation. Subsequently, concerted efforts have been made to increase the concentrations of cysteine and methionine in soybean seeds by both classical breeding and genetic engineering; however, these efforts have met with only limited success. In this review, we discuss the strengths and weakness of different approaches in elevating the sulfur amino acid content of soybeans. Manipulation of enzymes involved in the sulfur assimilatory pathway appears to be a viable avenue for improving sulfur amino acid content. This approach requires a through biochemical characterization of sulfur assimilatory enzymes in soybean seeds. We highlight recent studies targeting key sulfur assimilatory enzymes and the manipulation of sulfur metabolism in transgenic soybeans to improve the nutritive value of soybean proteins.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Leguminous plants can enter into root nodule symbioses with nitrogen-fixing soil bacteria known as rhizobia. An intriguing but still poorly understood property of the symbiosis is its host ...specificity, which is controlled at multiple levels involving both rhizobial and host genes. It is widely believed that the host specificity is determined by specific recognition of bacterially derived Nod factors by the cognate host receptor(s). Here we describe the positional cloning of two soybean genes Rj2 and Rfg1 that restrict nodulation with specific strains of Bradyrhizobium japonicum and Sinorhizobium fredii, respectively. We show that Rj2 and Rfg1 are allelic genes encoding a member of the Toll-interleukin receptor/nucleotide-binding site/leucine-rich repeat (TIR-NBS-LRR) class of plant resistance (R) proteins. The involvement of host R genes in the control of genotype-specific infection and nodulation reveals a common recognition mechanism underlying symbiotic and pathogenic host-bacteria interactions and suggests the existence of their cognate avirulence genes derived from rhizobia. This study suggests that establishment of a root nodule symbiosis requires the evasion of plant immune responses triggered by rhizobial effectors.
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Voltage angle-based torque control of dual three-phase interior permanent magnet synchronous machines (DTP-IPMSMs) in the field weakening (FW) region offers maximum dc voltage utilization, increased ...speed range, and higher torque capability. However, the difference in parameter values between the two three-phase winding sets results in torque limitations during FW operation. This article considers a dual three-phase IPMSM with 0<inline-formula><tex-math notation="LaTeX">^\circ</tex-math></inline-formula> winding displacement (DTP0 IPMSM), where the resistance and leakage inductance of each three-phase winding set are not the same. The effect of this parameter mismatch on the FW performance is discussed in detail. Further, a control scheme is proposed, where a 2-pole torque controller controls the torque dynamics by modifying the voltage angle of one of the inverters, while the other inverter's voltage angle is controlled to minimize the effect of parameter mismatch. The proposed method is implemented on a 3.68 kW DTP0 IPMSM prototype. For a given torque, the current requirement is shown to reduce approximately by 4% in the low and midspeed ranges of the FW region when compared with existing approaches of DTP0 IPMSM control. The performance of the 2-pole controller is also demonstrated, which achieves the desired control system specifications.
In legumes, the seed storage proteins accumulate within specialized organelles called protein storage vacuoles (PSVs). In several plant species, PSVs are differentiated into subdomains that ...accumulate different kinds of proteins. Even though the existence of subdomains is common in cereals and legumes, it has not been reported in soybean PSVs. The two most abundant seed proteins of soybean, 7S and 11S globulins, have different temporal accumulation patterns and exhibit considerable solubility differences that could result in differential accretion of these proteins within the PSVs. Here, we employed confocal fluorescent microscopy to examine the presence or absence of subdomains within the soybean PSVs. Eosin-stained sections of FAA-fixed paraffin embedded soybean seeds, when viewed by confocal fluorescence microscopy, revealed the presence of intricate subdomains within the PSVs. However, fluorescence immunolabeling studies demonstrated that the 7S and 11S globulins were evenly distributed within the PSVs and failed to corroborate the existence of subdomains within the PSVs. Similarly, confocal scanning microscopy examination of free-hand, vibratome and cryostat sections also failed to demonstrate the existence of subdomains within PSVs. The subdomains, which were prominently seen in PSVs of FAA-fixed soybean seeds, were not observed when the seeds were fixed either in glutaraldehyde/paraformaldehyde or glutaraldehyde. Our studies demonstrate that the apparent subdomains observed in FAA-fixed seeds may be a fixation artifact.
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IZUM, KILJ, NUK, PILJ, PNG, SAZU, UL, UM, UPUK
A total of 718 metabolites were identified in leaves and seeds of the soybean (Glycine max (L.) Merr., Fabaceae) fast neutron (FN) mutant 2012CM7F040p05ar154bMN15, which was previously shown to have ...21 genes deleted and higher protein content in seeds as compared to wild-type. Among the identified metabolites, 164 were found only in seeds, 89 only in leaves, and 465 in both leaves and seeds. Metabolites that exhibited higher abundance in the mutant leaf than in the wild type include the flavonoids afromosin, biochanin A, dihydrodaidzein, and apigenin. Mutant leaves also exhibited a higher accumulation of glycitein-glucoside, dihydrokaempferol, and pipecolate. The seed-only metabolites that were found in higher abundance in the mutant compared to the wild type included 3-hydroxybenzoate, 3-aminoisobutyrate, coenzyme A, N-acetyl-β-alanine, and 1-methylhistidine. Among several amino acids, the cysteine content increased in the mutant leaf and seed when compared to the wild type. We anticipate that the deletion of acetyl-CoA synthase created a negative feedback effect on carbon dynamics, resulting in increased amounts of cysteine and isoflavone-associated metabolites. Metabolic profiling provided new insight into the cascading effect of gene deletions that helps breeders to produce value-added nutritional seed traits.
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