Maitrayee DasGupta
Calcutta University, BIOCHEMISTRY, Faculty Member
Plant receptor-like kinases (RLKs) share their evolutionary origin with animal interleukin-1 recep- 31 tor-associated kinase (IRAK)/Pelle family of soluble kinases and are distinguished by having tyrosine 32 as ‘gatekeeper’. This position... more
Plant receptor-like kinases (RLKs) share their evolutionary origin with animal interleukin-1 recep- 31 tor-associated kinase (IRAK)/Pelle family of soluble kinases and are distinguished by having tyrosine 32 as ‘gatekeeper’. This position is adjacent to the hinge region and is hidden in a hydrophobic pocket 33 of the catalytic cleft of protein kinases and is therefore least probable to be a target for any modi- 34 fication. This communication illustrates the accessibility of the gatekeeper site (Y670) towards both 35 autophosphorylation and dephosphorylation in the recombinant cytoplasmic domain of symbiosis 36 receptor kinase from Arachis hypogaea (AhSYMRK). Autophosphorylation on gatekeeper tyrosine 37 was detected prior to extraction but never under in vitro conditions. We hypothesize gatekeeper 38 phosphorylation to be associated with synthesis/maturation of AhSYMRK and this phenomenon 39 may be prevalent among RLKs. 4041 Structured summary of protein interactions: 42AhSYMRK and ...
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Rhizobia–legume interactions recruit cytokinin for the induction of nodule primordia in the cortex. Cytokinin signaling regulates auxin transport and biosynthesis, causing local auxin accumulation, which triggers cortical cell division.... more
Rhizobia–legume interactions recruit cytokinin for the induction of nodule primordia in the cortex. Cytokinin signaling regulates auxin transport and biosynthesis, causing local auxin accumulation, which triggers cortical cell division. Since sugar signaling can trigger auxin responses, we explored whether sugar treatments could rescue symbiosis in the Medicago truncatula cytokinin response 1 (cre1) mutant. Herein, we demonstrate that sucrose and its nonmetabolizable isomer turanose can trigger auxin response and recover functional symbiosis in cre1, indicating sucrose signaling to be necessary for the restoration of symbiosis. In both M. truncatula A17 (wild type) and cre1, sucrose signaling significantly upregulated IAA-Ala Resistant 3 (IAR33), encoding an auxin conjugate hydrolase, in rhizobia-infected as well as in uninfected roots. Knockdown of IAR33 (IAR33-KD) significantly reduced nodulation in A17, highlighting the importance of deconjugation-mediated auxin accumulation duri...
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Nitrogenase that catalyses anaerobic symbiotic nitrogen fixation (SNF) in legumes is synthesized by rhizobium. Legume root cells express nodulin proteins after infection with rhizobia. Nodulins have been classified as early and late,... more
Nitrogenase that catalyses anaerobic symbiotic nitrogen fixation (SNF) in legumes is synthesized by rhizobium. Legume root cells express nodulin proteins after infection with rhizobia. Nodulins have been classified as early and late, reflecting the time points of their expression. Leghemoglobin (LegH), which is a classic example of a late nodulin, sequesters oxygen inside the nodule to protect the nitrogenase from oxygen toxicity to sustain SNF. Previous data from our laboratory demonstrated that phosphorylated LegH at S45 showed compromised oxygen sequestration in vitro due to structural disruption of the porphyrin binding pocket responsible for its oxygen binding. Moreover, we have demonstrated by using co-immunoprecipitation that LegH interacts both in vitro with Nodulin 16 of Lotus japonicus (Nlj16), another late nodulin. Fluorescence Immunohistochemistry (IHC) data shows that both LegH and Nlj16 are localized in the membrane and cytosol of infected cells. Notably, serine phosph...
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Jasmonate ZIM domain (JAZ) proteins are the key negative regulators of jasmonate signaling, an important integrator of plant-microbe relationships. Versatility of jasmonate signaling outcomes are maintained through the multiplicity of JAZ... more
Jasmonate ZIM domain (JAZ) proteins are the key negative regulators of jasmonate signaling, an important integrator of plant-microbe relationships. Versatility of jasmonate signaling outcomes are maintained through the multiplicity of JAZ proteins and their definitive functionalities. How jasmonate signaling influences the legume-Rhizobium symbiotic relationship is still unclear. In Arachis hypogaea (peanut), a legume plant, one JAZ sub-family (JAZ1) gene and one TIFY sequence containing protein family member (TIFY8) gene show enhanced expression in the early stage and late stage of root nodule symbiosis (RNS) respectively. In plants, JAZ sub-family proteins belong to a larger TIFY family. Here, this study denotes the first attempt to reveal in planta interactions of downstream jasmonate signaling regulators through proteomics and mass spectrometry to find out the mode of jasmonate signaling participation in the RNS process of A. hypogaea. From 4-day old Bradyrhizobium-infected peanut roots, the JAZ1-protein complex shows its contribution towards the rhizobial entry, nodule development, autoregulation of nodulation and photo-morphogenesis during the early stage of symbiosis. From 30-day old Bradyrhizobium infected roots, the TIFY8-protein complex reveals repressor functionality of TIFY8, suppression of root jasmonate signaling, modulation of root circadian rhythm and nodule development. Cellular localization and expression level of the interaction partners during the nodulation process further substantiate the in planta interaction pairs. This study provides a comprehensive insight into the jasmonate functionality in RNS through modulation of nodule number and development, during the early stage and root circadian rhythm during the late stage of nodulation, through the protein complexes of JAZ1 and TIFY8 respectively in A. hypogaea.
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The long noncoding RNA ENOD40 is required for cortical cell division during root nodule symbiosis (RNS) of legumes, though it is not essential for actinorhizal RNS. Our objective was to understand whether ENOD40 was required for... more
The long noncoding RNA ENOD40 is required for cortical cell division during root nodule symbiosis (RNS) of legumes, though it is not essential for actinorhizal RNS. Our objective was to understand whether ENOD40 was required for aeschynomenoid nodule formation in Arachis hypogaea. AhENOD40 express from chromosome 5 (chr5) (AhENOD40-1) and chr15 (AhENOD40-2) during symbiosis, and RNA interference of these transcripts drastically affected nodulation, indicating the importance of ENOD40 in A. hypogaea. Furthermore, we demonstrated several distinct characteristics of ENOD40. (i) Natural antisense transcript (NAT) of ENOD40 was detected from the AhENOD40-1 locus (designated as NAT-AhDONE40). (ii) Both AhENOD40-1 and AhENOD40-2 had two exons, whereas NAT-AhDONE40 was monoexonic. Reverse-transcription quantitative PCR analysis indicated both sense and antisense transcripts to be present in both cytoplasm and nucleus, and their expression increased with the progress of symbiosis. (iii) RNA ...
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Nitrogen is one of the essential plant nutrients and a major factor limiting crop productivity. To meet the requirements of sustainable agriculture, there is a need to maximize biological nitrogen fixation in different crop species.... more
Nitrogen is one of the essential plant nutrients and a major factor limiting crop productivity. To meet the requirements of sustainable agriculture, there is a need to maximize biological nitrogen fixation in different crop species. Legumes are able to establish root nodule symbiosis (RNS) with nitrogen-fixing soil bacteria which are collectively called rhizobia. This mutualistic association is highly specific, and each rhizobia species/strain interacts with only a specific group of legumes, and vice versa. Nodulation involves multiple phases of interactions ranging from initial bacterial attachment and infection establishment to late nodule development, characterized by a complex molecular signalling between plants and rhizobia. Characteristically, legumes like groundnut display a bacterial invasion strategy popularly known as “crack-entry’’ mechanism, which is reported approximately in 25% of all legumes. This article accommodates critical discussions on the bacterial infection mo...
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Rhizobia-legume interaction recruits cytokinin for the induction of nodule primordia in the cortex. In Medicago truncatula, cytokinin signalling involves flavonoid mediated local alteration of polar auxin transport for triggering cortical... more
Rhizobia-legume interaction recruits cytokinin for the induction of nodule primordia in the cortex. In Medicago truncatula, cytokinin signalling involves flavonoid mediated local alteration of polar auxin transport for triggering cortical cell division. Since sugar signalling is widely evidenced to trigger auxin responses, we explored whether sugar treatment could compensate for cytokinin signalling in M. truncatula cytokinin perception mutant cre1. Herein we demonstrate that turanose, a non-metabolizable sucrose analogue can trigger auxin response and show signs of recovery of symbiosis in cre1. Additionally, turanose upregulated the expression of WUSCHEL-related homeobox 5 (MtWOX5) which prompted us to check if overexpression of WOX5 could rescue cre1. Intriguingly, while overexpression of MtWOX5 failed, WOX5 from Arachis hypogaea (AhWOX5) completely restored functional symbiosis in cre1 with an efficiency resembling the wildtype. This indicate that indeterminate and determinate W...
ABSTRACTIn root-nodule symbiosis, rhizobial invasion and nodule organogenesis is host controlled. In most legumes, rhizobia enter through infection-threads and nodule primordium in the cortex is induced from a distance. But in dalbergoid... more
ABSTRACTIn root-nodule symbiosis, rhizobial invasion and nodule organogenesis is host controlled. In most legumes, rhizobia enter through infection-threads and nodule primordium in the cortex is induced from a distance. But in dalbergoid legumes like Arachis hypogaea, rhizobia directly invade cortical cells through epidermal cracks to generate the primordia. Herein we report the transcriptional dynamics with the progress of symbiosis in A. hypogaea at 1dpi: invasion; 4dpi: nodule primordia; 8dpi: spread of infection in nodule-like structure; 12dpi: immature nodules containing rod-shaped rhizobia; and 21dpi: mature nodules with spherical symbiosomes. Expression of putative orthologue of symbiotic genes in ‘crack-entry’ legume A. hypogaea was compared with infection thread adapted model legumes. The contrasting features were (i) higher expression of receptors like LYR3, EPR3 as compared to canonical NFRs (ii) late induction of transcription factors like NIN, NSP2 and constitutive high...
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In root-nodule symbiosis, rhizobial invasion and nodule organogenesis is host controlled. In most legumes, rhizobia enter through infection threads and nodule primordium in the cortex is induced from a distance. But in dalbergoid legumes... more
In root-nodule symbiosis, rhizobial invasion and nodule organogenesis is host controlled. In most legumes, rhizobia enter through infection threads and nodule primordium in the cortex is induced from a distance. But in dalbergoid legumes like Arachis hypogaea, rhizobia directly invade cortical cells through epidermal cracks to generate the primordia. Herein, we report the transcriptional dynamics with the progress of symbiosis in A. hypogaea at 1 day postinfection (dpi) (invasion), 4 dpi (nodule primordia), 8 dpi (spread of infection in nodule-like structure), 12 dpi (immature nodules containing rod-shaped rhizobia), and 21 dpi (mature nodules with spherical symbiosomes). Expression of putative ortholog of symbiotic genes in ‘crack entry’ legume A. hypogaea was compared with infection thread–adapted model legumes. The contrasting features were i) higher expression of receptors like LYR3 and EPR3 as compared with canonical Nod factor receptors, ii) late induction of transcription fac...
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The uphill energy transfer in photosystems implies input energy at higher wavelength leading to energy output at lower wavelength. Briefly, energy is uphill transported from photosystem I (PSI) to photosystem II (PSII), the latter having... more
The uphill energy transfer in photosystems implies input energy at higher wavelength leading to energy output at lower wavelength. Briefly, energy is uphill transported from photosystem I (PSI) to photosystem II (PSII), the latter having a lower wavelength emission. This uphill energy transport involves absorption of thermal energy from the surroundings. While such cooling effects have been reported in laser systems we report for the first time a white light driven cooling in thylakoid suspension. The cooling of the surrounding medium by appropriate illumination was illustrated using thermal measurements. Again cooling is inhibited by agents like 3-(3,4-Dichlorophenyl)-1,1-dimethylurea, that block the linear electron flow between the photocenters, implying a dependence of the cooling on interplay between such centers. Furthermore, it is possible to modulate the cooling pattern by addition of external agents like nanopaticles, some favoring further cooling (e.g., Ag nanoparticle) and...
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Cancer-associated p53 missense mutants confer gain of function (GOF) and promote tumorigenesis by regulating crucial signaling pathways. However, the role of GOF mutant p53 in regulating DNA replication, a commonly altered pathway in... more
Cancer-associated p53 missense mutants confer gain of function (GOF) and promote tumorigenesis by regulating crucial signaling pathways. However, the role of GOF mutant p53 in regulating DNA replication, a commonly altered pathway in cancer, is less explored. Here, we show that enhanced Cdc7-dependent replication initiation enables mutant p53 to confer oncogenic phenotypes. We demonstrate that mutant p53 cooperates with the oncogenic transcription factor Myb in vivo and transactivates Cdc7 in cancer cells. Moreover, mutant p53 cells exhibit enhanced levels of Dbf4, promoting the activity of Cdc7/Dbf4 complex. Chromatin enrichment of replication initiation factors and subsequent increase in origin firing confirm increased Cdc7-dependent replication initiation in mutant p53 cells. Further, knockdown of CDC7 significantly abrogates mutant p53-driven cancer phenotypes in vitro and in vivo Importantly, high CDC7 expression significantly correlates with p53 mutational status and predicts poor clinical outcome in lung adenocarcinoma patients. Collectively, this study highlights a novel functional interaction between mutant p53 and the DNA replication pathway in cancer cells. We propose that increased Cdc7-dependent replication initiation is a hallmark of p53 gain-of-function mutations.
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Bradyrhizobial invasion in dalbergoid legumes like Arachis hypogaea and endophytic bacterial invasions in non-legumes like Oryza sativa occur through epidermal cracks. Here we show that there is no overlap between the bradyrhizobial... more
Bradyrhizobial invasion in dalbergoid legumes like Arachis hypogaea and endophytic bacterial invasions in non-legumes like Oryza sativa occur through epidermal cracks. Here we show that there is no overlap between the bradyrhizobial consortia that endosymbiotically and endophytically colonise these plants. To minimise contrast due to phylogeographic isolation, strains were collected from Arachis/Oryza intercropped fields and a total of 17 bradyrhizobia from Arachis (WBAH) and 13 from Oryza (WBOS) were investigated. 16SrRNA and concatenated dnaK-glnII-recA phylogeny clustered the nodABC-positive WBAH and nodABC-deficient WBOS strains in two distinct clades. The in-field segregation is reproducible under controlled conditions which limits the factors that influence their competitive exclusion. While WBAH renodulated Arachis successfully, WBOS nodulated in an inefficient manner. Thus Arachis, like other Aeschynomene legumes support nod-independent symbiosis that was ineffectual in natu...
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Symbiosis receptor kinase (SYMRK) is indispensable for activation of root nodule symbiosis (RNS) at both epidermal and cortical levels and is functionally conserved in legumes. Previously we reported SYMRK to be phosphorylated on... more
Symbiosis receptor kinase (SYMRK) is indispensable for activation of root nodule symbiosis (RNS) at both epidermal and cortical levels and is functionally conserved in legumes. Previously we reported SYMRK to be phosphorylated on 'gatekeeper' Tyr both in vitro as well as in planta (Samaddar et al., 2013). Since gatekeeper phosphorylation was not necessary for activity, the significance remained elusive. Herein we show that substituting gatekeeper with non-phosphorylatable residues like Phe or Ala significantly affected autophosphorylation on selected targets on activation segment/αEF and β3 αC loop of SYMRK. In addition, the same gatekeeper mutants failed to restore proper symbiotic features in a symrk null mutant where rhizobial invasion of the epidermis and nodule organogenesis was unaffected but rhizobia remain restricted to the epidermis in infection threads migrating parallel to the longitudinal axis of the root resulting in extensive infection patches at the nodule ape...
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Plant receptor-like kinases (RLKs) are distinguished by having a tyrosine in the... more
Plant receptor-like kinases (RLKs) are distinguished by having a tyrosine in the 'gatekeeper' position. Previously we reported Symbiosis Receptor Kinase from Arachis hypogaea (AhSYMRK) to autophosphorylate on the gatekeeper tyrosine (Y670), though this phosphorylation was not necessary for the kinase activity. Here we report that recombinant catalytic domain of AhSYMRK with a phosphomimic substitution in the gatekeeper position (Y670E) is catalytically almost inactive and is conformationally quite distinct from the corresponding native enzyme. Additionally, we show that gatekeeper-phosphorylated AhSYMRK polypeptides are inactive and depletion of this inactive form leads to activation of intramolecular autophosphorylation of AhSYMRK. Together, our results suggest gatekeeper tyrosine autophosphorylation to be autoinhibitory for AhSYMRK.
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Amplification of the light driven photosynthetic circuit (P723/P689) by static magnetic field leading to a reversible and controllable uncoupler (N denotes nigericin).
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Symbiosis Receptor Kinase (SYMRK), a member of the Nod factor signaling pathway, is indispensible for both nodule organogenesis and intracellular colonization of symbionts in rhizobia-legume symbiosis. Here, we show that the intracellular... more
Symbiosis Receptor Kinase (SYMRK), a member of the Nod factor signaling pathway, is indispensible for both nodule organogenesis and intracellular colonization of symbionts in rhizobia-legume symbiosis. Here, we show that the intracellular kinase domain of a SYMRK (SYMRK-kd) but not its inactive or full-length version leads to hyperactivation of the nodule organogenic program in Medicago truncatula TR25 (symrk knockout mutant) in the absence of rhizobia. Spontaneous nodulation in TR25/SYMRK-kd was 6-fold higher than rhizobia-induced nodulation in TR25/SYMRK roots. The merged clusters of spontaneous nodules indicated that TR25 roots in the presence of SYMRK-kd have overcome the control over both nodule numbers and their spatial position. In the presence of rhizobia, SYMRK-kd could rescue the epidermal infection processes in TR25, but colonization of symbionts in the nodule interior was significantly compromised. In summary, ligand-independent deregulated activation of SYMRK hyperactiv...
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Research Interests: Genetics, Plant Biology, Transcription Factors, Plant Molecular Biology, Mutation, and 12 moreAbscisic Acid, Auxin, Phaseolus vulgaris, DNA binding, Amino Acid Sequence, Base Sequence, Protein Binding, Arachis Hypogaea, PLANT PROTEINS, Biochemistry and cell biology, Molecular Sequence Data, and purines
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In legume–rhizobia symbiosis, Ca2+/calmodulin-dependent protein kinase (CCaMK) is essential for rhizobial invasion through infection threads in the epidermis and nodule organogenesis in the cortex. Though CCaMK is actively transcribed in... more
In legume–rhizobia symbiosis, Ca2+/calmodulin-dependent protein kinase (CCaMK) is essential for rhizobial invasion through infection threads in the epidermis and nodule organogenesis in the cortex. Though CCaMK is actively transcribed in the infected zone of nodules, its role in the later stages of nodule development remain elusive because of the epidermal arrest of “loss-of-function” mutants. In Aeschynomeneae legumes such as Arachis hypogea, rhizobia directly access the cortex, where nodule organogenesis as well as endosymbiont dissemination take place by multiplication of infected cortical cells. We characterized CCaMK (GI:195542474) from A. hypogea and downregulated the kinase through RNA interference (RNAi) to understand its role during organogenesis of its characteristic aeschynomenoid nodules. In CCaMK downregulated plants, the inception of nodules was delayed by approximately 4 weeks and nodulation capacity was decreased (>90%). The infected zones of the RNA interference ...
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Research Interests: Protein Folding, Kinetics, Calcium, Biological Chemistry, Biological Sciences, and 15 moreDomain Analysis, Circular Dichroism, NUTS, Biological, Peptides, CHEMICAL SCIENCES, Cell nucleus, Protein Conformation, Glutathione Transferase, Amino Acid Sequence, Protein Binding, Arachis Hypogaea, Allergy and Immunology, Molecular Sequence Data, and Medical and Health Sciences
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Plant receptor-like kinases (RLKs) share their evolutionary origin with animal interleukin-1 receptor-associated kinase (IRAK)/Pelle family of soluble kinases and are distinguished by having tyrosine as... more
Plant receptor-like kinases (RLKs) share their evolutionary origin with animal interleukin-1 receptor-associated kinase (IRAK)/Pelle family of soluble kinases and are distinguished by having tyrosine as 'gatekeeper'. This position is adjacent to the hinge region and is hidden in a hydrophobic pocket of the catalytic cleft of protein kinases and is therefore least probable to be a target for any modification. This communication illustrates the accessibility of the gatekeeper site (Y670) towards both autophosphorylation and dephosphorylation in the recombinant cytoplasmic domain of symbiosis receptor kinase from Arachis hypogaea (AhSYMRK). Autophosphorylation on gatekeeper tyrosine was detected prior to extraction but never under in vitro conditions. We hypothesize gatekeeper phosphorylation to be associated with synthesis/maturation of AhSYMRK and this phenomenon may be prevalent among RLKs.
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Downregulation of phosphorylation of chlorophyll a/b-binding proteins (LHCII) of the photosystem II at high irradiance could only be demonstrated with leaf discs but not in isolated thylakoids. The present view suggests this phenomenon to... more
Downregulation of phosphorylation of chlorophyll a/b-binding proteins (LHCII) of the photosystem II at high irradiance could only be demonstrated with leaf discs but not in isolated thylakoids. The present view suggests this phenomenon to be regulated by stromal thioredoxin. Here, we show that high-light inactivation of LHCII phosphorylation can be reproduced in isolated thylakoids and have explained the apparent absence of inactivation in vitro to be due to the derepressed activity of a peripheral kinase. We investigated this phenomenon with Arachis hypogea thylakoids prepared with (Th:A) or without (Th:B) tricine, where tricine is known for removing peripheral proteins from thylakoids. While LHCII remained phosphorylated at high irradiance in Th:B, the response of Th:A mimicked Arachis leaflets where LHCII was transiently phosphorylated with irradiance. LHCII phosphorylation in Th:A was sensitive to thiol reducing conditions, but in Th:B, the phenomenon became insensitive to thiol reduction following illumination. Washing Th:B with tricine made them resemble Th:A, and conversely, Th:A reconstituted with the Tricine extract resembled Th:B with respect to both irradiance response and thiol sensitivity. In vitro phosphorylation reactions indicated a thiol insensitive kinase activity to be present in the Tricine extract that was capable of phosphorylating histone H1 as well as purified LHCII. This peripherally associated kinase activity explained the sustenance of LHCII phosphorylation as well as its thiol insensitivity at high irradiance in Th:B thylakoids. Contrary to the current view, our results clearly show that irradiance dependent phosphorylation and dephosphorylation of LHCII is a thylakoid sufficient phenomenon, although it remained open to regulation by thiol redox state modulation.