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2.
ACS Appl Mater Interfaces ; 16(7): 8627-8638, 2024 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-38345507

RESUMEN

Chemical stability of hexagonal boron nitride (hBN) ultrathin layers in harsh electrolytes and the availability of nitrogen site in hBN to stabilize metals like Pt are used here to develop a high intrinsic activity hydrogen evolution reaction (HER) catalyst having low loaded Pt (5 weight% or <1 atomic%). A catalyst having a nonzero oxidation state for Pt (with a Pt-N bonding) is shown to be HER active even with low catalyst loadings (0.114 mgcm-2). Electronic modification of the shear exfoliated hBN sheets is achieved by Au nanoparticle-based surface decoration (hBN_Au), and further anchoring with Pt develops a catalyst (hBN_Au_Pt) with high turnover frequency for HER (∼15). The hBN_Au_Pt is shown to be a highly durable catalyst even after the accelerated durability test for 10000 cycles and temperature annealing at 100 °C. Density functional theory based calculations gave insights in to the electronic modifications of hBN with Au and the catalytic activity of the hBN_Au_Pt system, in line with the experimental studies, indicating the demonstration of a new class of catalyst system devoid of issues such as carbon corrosion and Pt leaching.

3.
Nanoscale ; 15(30): 12694-12709, 2023 Aug 03.
Artículo en Inglés | MEDLINE | ID: mdl-37470330

RESUMEN

Layered transition metal dichalcogenides (TMDs) have shown commendable properties for spintronic applications. From the device perspective, the structural quality of the TMD as well as its interface with the adjacent ferromagnetic (FM) layer is of paramount importance. Here, we present the spin-dynamic behaviour in the widely studied TMDs, i.e., MoS2 using Co60Fe20B20 (CoFeB), i.e., in MoS2(1-4 layers)/CoFeB(4-15 nm) heterostructures, both in the as-grown state and in the in situ annealed state (400 °C in a vacuum). Raman spectroscopy revealed systematic variation in the separation (δ) between the characteristic Raman shifts corresponding to the E2g and A1gvis-à-vis the number of layers (nL) of MoS2. The analysis of the ferromagnetic resonance (FMR) spectroscopy measurements performed on these heterostructures revealed the spin pumping from CoFeB to the MoS2 layer as evidenced by the ∼49% (∼51%) enhancement in the effective damping parameter with respect to the damping parameter of bare as-deposited (annealed) CoFeB films. This enhancement is attributed to the spin-pumping owing to the high spin-orbit coupling of monolayer MoS2. The latter is also confirmed by density functional theory calculations. By finding the effective spin mixing conductance of the MoS2/CoFeB interface, the effective spin current density in the MoS2 layer is estimated to increase from ∼0.3 to 0.7 MA m-2 with CoFeB thickness for both the as-deposited and annealed heterostructures. Furthermore, the δ vs. nL curve of the as-deposited heterostructure did not show any significant change upon annealing, which demonstrated that the spin transport and magnetic properties of these heterostructures remained unaffected even after annealing at a high temperature of 400 °C. Hence, this establishes the high thermal stability of the sputter grown MoS2/CoFeB heterostructures. Thus, this study highlights the important role of MoS2 as an efficient spin current-generating source for spin-orbit torque based magnetic memory applications, given the high-temperature stability and high-quality monolayers of MoS2 and its excellent performance with CoFeB thin films.

4.
Small ; 19(38): e2303319, 2023 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-37194967

RESUMEN

Photo-rechargeable (solar) battery can be considered as an energy harvesting cum storage system, where it can charge the conventional metal-ion battery using light instead of electricity, without having other parasitic reactions. Here a two-electrode lithium-ion solar battery with multifaceted TiS2 -TiO2 hybrid sheets as cathode. The choice of TiS2 -TiO2 electrode ensures the formation of a type II semiconductor heterostructure while the lateral heterostructure geometry ensures high mass/charge transfer and light interactions with the electrode. TiS2 has a higher lithium binding energy (1.6 eV) than TiO2 (1.03 eV), ensuring the possibilities of higher amount of Li-ion insertion to TiS2 and hence the maximum recovery with the photocharging, as further confirmed by the experiments. Apart from the demonstration of solar solid-state batteries, the charging of lithium-ion full cell with light indicates the formation of lithium intercalated graphite compounds, ensuring the charging of the battery without any other parasitic reactions at the electrolyte or electrode-electrolyte interfaces. Possible mechanisms proposed here for the charging and discharging processes of solar batteries, based on the experimental and theoretical results, indicate the potential of such systems in the forthcoming era of renewable energies.

5.
Nanoscale ; 15(1): 337-349, 2022 Dec 22.
Artículo en Inglés | MEDLINE | ID: mdl-36503983

RESUMEN

Spin gapless semiconductors (SGSs) are an intriguing class of quantum materials that bridge the gap between half-metallic ferromagnets and semiconductors. The presence of a semiconducting bandgap for one spin channel and zero band gap for other spin channels, together with the possibility of four different band structure configurations, makes them one of the most desirable candidates to be used in tunable spin transport based spintronics devices. Here, we have performed various structural, magnetic and transport measurements on an optimized CoFeCrGa (CFCG) Heusler alloy thin film (∼50 nm) grown over a Si(100) substrate using an industry-viable magnetron sputtering technique. The grown film showed B2-ordering under the given set of X-ray diffraction measurement conditions with a saturation magnetization (Ms) of 1.86µB per f.u. (at 5 K) and a Curie temperature of ∼595 K. Nearly linearly varying longitudinal resistivity with a negative temperature coefficient was observed. A fitted longitudinal conductivity curve through a "two-carrier model" shows a slight band overlap in the gapless channel for one spin channel and a small energy gap (ΔE) of 167 meV for other spin channels. A negative and linear out-of-plane magnetoresistance response was observed in these films. The temperature dependent anomalous Hall effect measurement gives nearly temperature independent carrier concentration (and/or) mobility with an anomalous Hall conductivity of 91.35 S cm-1 at 5 K. The first principles calculations have also been performed for bulk and (220) CFCG surfaces to correlate the various structural, electronics and magnetic properties of the optimized CFCG Heusler alloy thin film. The DFT derived results, viz. lattice parameter and MS exhibit a good match with the experimentally observed results. All these properties collectively imply that the grown film possesses disordered-SGS like behaviour. It is remarkable to note that CFCG films with the (022) surface possess a very high electronic spin polarization of 91%. The results of the study suggest that CFCG is a potential candidate to be used in spintronics-based devices such as spin-injectors.

6.
Plant Genome ; 15(3): e20234, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35762493

RESUMEN

Black gram [Vigna mungo (L.) Hepper var. mungo] is a warm-season legume highly prized for its protein content along with significant folate and iron proportions. To expedite the genetic enhancement of black gram, a high-quality draft genome from the center of origin of the crop is indispensable. Here, we established a draft genome sequence of an Indian black gram cultivar, 'Uttara' (IPU 94-1), known for its high resistance to mungbean yellow mosaic virus. Pacific Biosciences of California, Inc. (PacBio) single-molecule real-time (SMRT) and Illumina sequencing assembled a draft reference-guided assembly with a cumulative size of ∼454.4 Mb, of which, 444.4 Mb was anchored on 11 pseudomolecules corresponding to 11 chromosomes. Uttara assembly denotes features of a high-quality draft genome illustrated through high N50 value (42.88 Mb), gene completeness (benchmarking universal single-copy ortholog [BUSCO] score 94.17%) and low levels of ambiguous nucleotides (N) percent (0.0005%). Gene discovery using transcript evidence predicted 28,881 protein-coding genes, from which, ∼95% were functionally annotated. A global survey of genes associated with disease resistance revealed 119 nucleotide binding site-leucine rich repeat (NBS-LRR) proteins, while 23 genes encoding seed storage proteins (SSPs) were discovered in black gram. A large set of microsatellite loci were discovered for marker development in the crop. Our draft genome of an Indian black gram provides the foundational genomic resources for the improvement of important agronomic traits and ultimately will help in accelerating black gram breeding programs.


Asunto(s)
Vigna , Resistencia a la Enfermedad/genética , Ácido Fólico , Hierro , Leucina/genética , Nucleótidos , Fitomejoramiento , Proteínas de Almacenamiento de Semillas/genética , Análisis de Secuencia de ADN , Vigna/genética
7.
Angew Chem Int Ed Engl ; 61(28): e202202637, 2022 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-35362643

RESUMEN

Herein we report secondary pyrrolidin-2-ols as a source of cyclic (alkyl)(amino)carbenes (CAAC) for the synthesis of CAAC-CuI -complexes and cyclic thiones when reacted with CuI -salts and elemental sulfur, respectively, under reductive elimination of water from the carbon(IV)-center. This result demonstrates a convenient and facile access to CAAC-based CuI -salts, which are well known catalysts for different organic transformations. It further establishes secondary alcohols to be a viable source of carbenes-realizing after 185 years Dumas' dream who tried to prepare the parent carbene (CH2 ) by 1,1-dehydration of methanol. Addressed is also the reactivity of water towards CAACs, which proceeds through an oxidative addition of the O-H bond to the carbon(II)-center. This emphasizes the ability of carbon-compounds to mimic the reactivity of transition-metal complexes: reversible oxidative addition and reductive elimination of the O-H bond to/from the C(II)/C(IV)-centre.

8.
Small ; 17(51): e2105029, 2021 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-34786850

RESUMEN

New ways of directly using solar energy to charge electrochemical energy storage devices such as batteries would lead to exciting developments in energy technologies. Here, a two-electrode photo rechargeable Li-ion battery is demonstrated using nanorod of type II semiconductor heterostructures with in-plane domains of crystalline MoS2 and amorphous MoOx . The staggered energy band alignment of MoS2 and MoOx limits the electron holes recombination and causes holes to be retained in the Li intercalated MoS2 electrode. The holes generated in the MoS2 pushes the intercalated Li-ions and hence charge the battery. Low band gap, high efficiency photo-conversion and efficient electron-hole separation help the battery to fully charge within a few hours using solar light. The proposed concept and materials can enable next generation stable photo-rechargeable battery electrodes, in contrast to the reported materials.

9.
J Exp Bot ; 71(17): 5280-5293, 2020 08 17.
Artículo en Inglés | MEDLINE | ID: mdl-32526034

RESUMEN

Limited information is available on abiotic stress-mediated alterations of chromatin conformation influencing gene expression in plants. In order to characterize the effect of abiotic stresses on changes in chromatin conformation, we employed FAIRE-seq (formaldehyde-assisted isolation of regulatory element sequencing) and DNase-seq to isolate accessible regions of chromatin from Arabidopsis thaliana seedlings exposed to either heat, cold, salt, or drought stress. Approximately 25% of regions in the Arabidopsis genome were captured as open chromatin, the majority of which included promoters and exons. A large proportion of chromatin regions apparently did not change their conformation in response to any of the four stresses. Digital footprints present within these regions had differential enrichment of motifs for binding of 43 different transcription factors. Further, in contrast to drought and salt stress, both high and low temperature treatments resulted in increased accessibility of the chromatin. Also, pseudogenes attained increased chromatin accessibility in response to cold and drought stresses. The highly accessible and inaccessible chromatin regions of seedlings exposed to drought stress correlated with the Ser/Thr protein kinases (MLK1 and MLK2)-mediated reduction and increase in H3 phosphorylation (H3T3Ph), respectively. The presented results provide a deeper understanding of abiotic stress-mediated chromatin modulation in plants.


Asunto(s)
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Cromatina , Sequías , Regulación de la Expresión Génica de las Plantas , Plantas Modificadas Genéticamente/metabolismo , Estrés Fisiológico
11.
Opt Lett ; 44(7): 1770-1773, 2019 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-30933143

RESUMEN

We design and experimentally demonstrate a broadband 1310/1550 nm wavelength demultiplexer based on a multimode interference coupler with a tapered internal photonic crystal (PC) structure for the silicon-on-insulator platform. The tapered internal PC structure is engineered to reflect the C-band light while transmitting the O-band light. Novel PC nanotapers are introduced for the internal PC structure that effectively suppress the sidelobe of the photonic bandgap and enable our device to be operable over the O-band. The device was fabricated using electron beam lithography, and its performance has been experimentally characterized. The measured extinction ratios are higher than 15 dB over a 74 nm bandwidth from 1286 to 1360 nm at the O-band, and over a 103 nm bandwidth from 1527 to 1630 nm that covers the C-band and the L-band.

12.
Int J Urol ; 26(5): 551-557, 2019 05.
Artículo en Inglés | MEDLINE | ID: mdl-30803052

RESUMEN

OBJECTIVE: To assess renal unit survival and factors affecting renal salvageability in a cohort of patients receiving modern medical and surgical therapy for urinary tuberculosis. METHODS: This was a retrospective single-center study including all patients diagnosed and treated as urinary tuberculosis between 2005 and 2015 at Christian Medical College, Vellore, Tamil Nadu, India. The primary outcome was time to renal unit non-salvageability (estimated glomerular filtration rate of <15 mL/min). RESULTS: A total of 128 patients were included in the study. The mean age was 37.7 ± 11.3 years, 33% had microbiological and 73% had histopathological confirmation in addition to radiological diagnosis. The estimated median survival of the involved renal units (n = 187) on Kaplan-Meier estimate was 75 months (95% CI 39-99). On multivariate analysis, renal units with initial split function >15 mL/min had fivefold the survival estimate as compared with those ≤15 mL/min (P < 0.001); the presence of one, two and three infundibular strictures had a 2.2-, 2.9- and fivefold higher hazard of renal unit loss respectively, and lower ureteric strictures had fivefold longer estimated survival (P = 0.015) after treatment. Renal units in the reconstruction group had 5.44-fold (95% CI 2.71-10.88, P < 0.001) longer survival than the permanent diversion group, with a mean change in split function of +0.76 (±16.11) mL/min, versus -5.61 (±10.87) mL/min respectively. CONCLUSIONS: Loss of renal units is a function of time despite modern treatment. Baseline renal unit function, site of ureteric involvement and extent of infundibular involvement on imaging are helpful in predicting the duration of renal salvageability. When feasible, reconstruction is better at renal function preservation.


Asunto(s)
Riñón/cirugía , Tuberculosis Urogenital/terapia , Adulto , Antituberculosos/uso terapéutico , Femenino , Tasa de Filtración Glomerular , Humanos , India , Estimación de Kaplan-Meier , Riñón/diagnóstico por imagen , Masculino , Persona de Mediana Edad , Análisis Multivariante , Mycobacterium tuberculosis/efectos de los fármacos , Nefrectomía , Valor Predictivo de las Pruebas , Radiografía , Estudios Retrospectivos , Terapia Recuperativa , Tuberculosis Urogenital/diagnóstico por imagen , Ultrasonografía
13.
Leukemia ; 33(7): 1675-1686, 2019 07.
Artículo en Inglés | MEDLINE | ID: mdl-30664664

RESUMEN

p97 is an ATPase that works in concert with histone deacetylase 6 (HDAC6), to facilitate the degradation of misfolded proteins by autophagosomes. p97 has also been implicated in DNA repair and maintaining genomic stability. In this study, we determined the effect of combined inhibition of p97 and HDAC6 activities in mantle cell lymphoma (MCL) cells. We report that treatment with p97 inhibitors induces dose-dependent apoptosis in MCL cells. The p97 inhibitor CB-5083 induces ER stress markers GRP78 and CHOP and results in the accumulation of polyubiquitylated proteins. Co-treatment with CB-5083 and the HDAC6 inhibitor ACY-1215 result in marked downregulation of CDK4, Cyclin D1, and BRCA1 levels without inhibiting autophagic flux. Consequently, treatment with CB-5083 accentuates DNA damage in response to treatment with ACY-1215 resulting in enhanced accumulation of H2AX-γ and synergistic apoptosis. Furthermore, ATM loss severely impairs phosphorylation of 53BP1 following co-treatment with CB-5083 and ACY-1215 in response to gamma irradiation. Finally, co-treatment CB-5083 and ACY-1215 results in reduced tumor volumes and improves survival in Z138C and Jeko-1 xenografts in NSG mice. These observations suggest that combined inhibition of p97 and HDAC6 abrogates resolution of proteotoxic stress and impairs DNA repair mechanisms in MCL cells.


Asunto(s)
Adenosina Trifosfatasas/antagonistas & inhibidores , Reparación del ADN/efectos de los fármacos , Sinergismo Farmacológico , Histona Desacetilasa 6/antagonistas & inhibidores , Ácidos Hidroxámicos/farmacología , Indoles/farmacología , Linfoma de Células del Manto/tratamiento farmacológico , Linfoma de Células del Manto/genética , Proteínas Nucleares/antagonistas & inhibidores , Pirimidinas/farmacología , Animales , Apoptosis , Autofagia , Proliferación Celular , Daño del ADN/efectos de los fármacos , Quimioterapia Combinada , Chaperón BiP del Retículo Endoplásmico , Regulación Neoplásica de la Expresión Génica , Inhibidores de Histona Desacetilasas/farmacología , Humanos , Linfoma de Células del Manto/patología , Ratones , Ratones Endogámicos NOD , Ratones SCID , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto
14.
Opt Express ; 26(23): 29873-29885, 2018 Nov 12.
Artículo en Inglés | MEDLINE | ID: mdl-30469946

RESUMEN

We demonstrate a compact high-performance adiabatic 3-dB coupler for the silicon-on-insulator platform. The refractive index of the gap region between two coupling waveguides is effectively increased using subwavelength grating, which leads to high-performance operation and a compact design footprint, with a mode-evolution length of only 25 µm and an entire device length of 65 µm. The designed adiabatic 3-dB coupler has been fabricated using electron beam lithography and the feature size used in our design is CMOS compatible. The fabricated device is characterized in the wavelength range from 1500 nm to 1600 nm, with a measured power splitting ratio better than 3 ± 0.27 dB and an average insertion loss of 0.20 dB.

15.
Opt Express ; 26(16): 19742-19749, 2018 Aug 06.
Artículo en Inglés | MEDLINE | ID: mdl-30119295

RESUMEN

We present the first demonstration of a 4λ transmitter optical sub-assembly (TOSA) on the coarse wavelength division multiplexing (CWDM) grid, i.e., 20 nm spacing, targeting 400G-FR4 requirements over 2 km. The TOSA is based on uncooled InP external modulated laser (EML) technology and it utilizes four EMLs followed by a CWDM multiplexer. We characterize the performance of the TOSA versus received optical modulation amplitude (OMA), number of equalizer taps, reach, modulation format, TOSA case temperature, and bit rate. Four 53 Gbaud 4-level pulse amplitude modulation (PAM4) RF signals are used to drive the TOSA achieving a net rate of 400 Gb/s. Results reveal that 400 Gb/s can be transmitted over 2 km of single mode fiber (SMF) at a bit error rate (BER) below the KP4- forward error correction (KP4-FEC) threshold (i.e., 2.4 × 10-4) using only a 5 tap feed forward equalizer at the receiver. To the best of our knowledge, this is the first demonstration of 400 Gb/s using a 4λ CWDM TOSA over 2 km of SMF. Moreover, we achieve 400 Gb/s and 600 Gb/s over 20 km and 10 km below KP4-FEC and the 7% hard-decision FEC (HD-FEC) (i.e., 3.8 × 10-3) thresholds, respectively, without optical amplification. Furthermore, we show the performance of the TOSA against temperature, where it shows no significant change in the BER performance from 20 °C to 60 °C. Finally, we compare the performance of PAM2, PAM4, and PAM8 modulation formats where we show the possibility of achieving 400 Gb/s aggregate bit rate using 42 Gbaud PAM8 modulation format at the expense of utilizing a stronger FEC.

16.
Front Plant Sci ; 9: 402, 2018.
Artículo en Inglés | MEDLINE | ID: mdl-29651296

RESUMEN

Carthamus tinctorius L. (safflower) is an important oilseed crop producing seed oil rich in unsaturated fatty acids. Scarcity of identified marker-trait associations is a major limitation toward development of successful marker-assisted breeding programs in safflower. In the present study, a safflower panel (CartAP) comprising 124 accessions derived from two core collections was assayed for its suitability for association mapping. Genotyping of CartAP using microsatellite markers revealed significant genetic diversity indicated by Shannon information index (H = 0.7537) and Nei's expected heterozygosity (I = 0.4432). In Principal Coordinate Analysis, the CartAP accessions were distributed homogeneously in all quadrants indicating their diverse nature. Distance-based Neighbor Joining analysis did not delineate the CartAP accessions in consonance with their geographical origin. Bayesian analysis of population structure of CartAP demonstrated the unstructured nature of the association panel. Kinship analysis at population (Gij ) and individual level (Fij ) revealed absence of or weak relatedness between the CartAP accessions. The above parameters established the suitability of CartAP for association mapping. We performed association mapping using phenotypic data for eight traits of agronomic value (viz., seed oil content, oleic acid, linoleic acid, plant height, number of primary branches, number of capitula per plant, 100-seed weight and days to 50% flowering) available for two growing seasons (2011-2012 and 2012-2013) through General Linear Model and Mixed Linear Model. Our study identified ninety-six significant marker-trait associations (MTAs; P < 0.05) of which, several MTAs with correlation coefficient (R2) > 10% were consistently represented in both models and in both seasons for traits viz., oil content, oleic acid content, linoleic acid content and number of primary branches. Several MTAs with high R2-values were detected either in a majority or in some environments (models and/or seasons). Many MTAs were also common between traits (viz., oleic/linoleic acid content; plant height/days to 50% flowering; number of primary branches/number of capitula per plant) that showed positive or negative correlation in their phenotypic values. The marker-trait associations identified in this study will facilitate marker-assisted breeding and identification of genetic determinants of trait variability.

17.
Mol Plant Pathol ; 19(3): 615-633, 2018 03.
Artículo en Inglés | MEDLINE | ID: mdl-28220591

RESUMEN

Root-knot nematodes (RKNs, Meloidogyne incognita) are economically important endoparasites with a wide host range. We used a comprehensive transcriptomic approach to investigate the expression of both tomato and RKN genes in tomato roots at five infection time intervals from susceptible plants and two infection time intervals from resistant plants, grown under soil conditions. Differentially expressed genes during susceptible (1827, tomato; 462, RKN) and resistance (25, tomato; 160, RKN) interactions were identified. In susceptible responses, tomato genes involved in cell wall structure, development, primary and secondary metabolite, and defence signalling pathways, together with RKN genes involved in host parasitism, development and defence, are discussed. In resistance responses, tomato genes involved in secondary metabolite and hormone-mediated defence responses, together with RKN genes involved in starvation stress-induced apoptosis, are discussed. In addition, 40 novel differentially expressed RKN genes encoding secretory proteins were identified. Our findings provide novel insights into the temporal regulation of genes involved in various biological processes from tomato and RKN simultaneously during susceptible and resistance responses, and reveal the involvement of a complex network of biosynthetic pathways during disease development.


Asunto(s)
Enfermedades de las Plantas/genética , Enfermedades de las Plantas/parasitología , Solanum lycopersicum/genética , Solanum lycopersicum/parasitología , Transcriptoma/genética , Tylenchoidea/patogenicidad , Animales , Regulación de la Expresión Génica de las Plantas/genética , Regulación de la Expresión Génica de las Plantas/fisiología , Interacciones Huésped-Parásitos/genética , Interacciones Huésped-Parásitos/fisiología , Solanum lycopersicum/metabolismo , Raíces de Plantas/genética , Raíces de Plantas/metabolismo , Raíces de Plantas/parasitología
18.
Opt Express ; 25(24): 30582-30590, 2017 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-29221085

RESUMEN

We demonstrate two single-etched sub-wavelength grating coupler (SWGC) designs for O-band application, one targeting at high coupling efficiency and the other targeting at broad operating bandwidth. The high-efficiency SWGC has a measured peak coupling efficiency of -3.8 dB and a 3-dB bandwidth of 40 nm, and the broadband SWGC has a measured peak coupling efficiency of -4.3 dB and a 3-dB bandwidth of 71 nm. Focusing gratings have been used in our SWGCs to reduce the design footprints and the dimensions of our SWGCs are smaller than 45 µm × 24 µm. The back reflections of our SWGCs are suppressed to be below -15 dB over the wavelength range from 1260 nm to 1360 nm.

19.
PLoS One ; 12(4): e0175178, 2017.
Artículo en Inglés | MEDLINE | ID: mdl-28426683

RESUMEN

Root-knot nematodes (RKNs, Meloidogyne spp.) are the most damaging plant parasites causing severe losses to crop production. The present study reports genome-wide identification and characterization of both tomato and RKN miRNAs simultaneously from RKN-infected susceptible tomato roots using high-throughput sequencing technique. RNAseq data from 11 small RNA libraries derived from 5 disease development stages identified 281 novel miRNAs of tomato in addition to 52 conserved and 4 variants of conserved miRNAs. Additionally, the same set of RNAseq data identified 38 conserved and 290 novel RKN miRNAs. Both tomato and RKN miRNAs showed differential expression at 5 stages of disease development based on digital expression profiles. In tomato, further validation through qRT-PCR confirmed that majority of miRNAs were significantly upregulated during susceptible response whereas downregulated during resistance response. The predicted targets of 8 conserved and 1 novel miRNAs were validated through 5'RLM-RACE. A negative correlation between expression profiles of a few conserved miRNAs (miR156, miR159, miR164 and miR396) and their targets (SBP, GAMYB-like, NAC and GRF1 transcription factor) was confirmed. A novel Sly_miRNA996 also showed a negative correlation with its target MYB-like transcription factor. These results indicate that the conserved and novel tomato miRNAs are involved in regulating developmental changes in host root during RKN infection. In RKN, the targets of conserved miRNAs were also predicted and a few of their predicted target genes are known to be involved in nematode parasitism. Further, the potential roles of both tomato and RKN miRNAs have been discussed.


Asunto(s)
MicroARNs/genética , Raíces de Plantas/genética , Solanum lycopersicum/parasitología , Tylenchoidea/patogenicidad , Animales , Interacciones Huésped-Parásitos , Solanum lycopersicum/genética
20.
Front Plant Sci ; 7: 1554, 2016.
Artículo en Inglés | MEDLINE | ID: mdl-27807441

RESUMEN

Safflower (Carthamus tinctorius L.) is a dryland oilseed crop yielding high quality edible oil. Previous studies have described significant phenotypic variability in the crop and used geographical distribution and phenotypic trait values to develop core collections. However, the molecular diversity component was lacking in the earlier collections thereby limiting their utility in breeding programs. The present study evaluated the phenotypic variability for 12 agronomically important traits during two growing seasons (2011-12 and 2012-13) in a global reference collection of 531 safflower accessions, assessed earlier by our group for genetic diversity and population structure using AFLP markers. Significant phenotypic variation was observed for all the agronomic traits in the representative collection. Cluster analysis of phenotypic data grouped the accessions into five major clusters. Accessions from the Indian Subcontinent and America harbored maximal phenotypic variability with unique characters for a few traits. MANOVA analysis indicated significant interaction between genotypes and environment for both the seasons. Initially, six independent core collections (CC1-CC6) were developed using molecular marker and phenotypic data for two seasons through POWERCORE and MSTRAT. These collections captured the entire range of trait variability but failed to include complete genetic diversity represented in 19 clusters reported earlier through Bayesian analysis of population structure (BAPS). Therefore, we merged the three POWERCORE core collections (CC1-CC3) to generate a composite core collection, CartC1 and three MSTRAT core collections (CC4-CC6) to generate another composite core collection, CartC2. The mean difference percentage, variance difference percentage, variable rate of coefficient of variance percentage, coincidence rate of range percentage, Shannon's diversity index, and Nei's gene diversity for CartC1 were 11.2, 43.7, 132.4, 93.4, 0.47, and 0.306, respectively while the corresponding values for CartC2 were 9.3, 58.8, 124.6, 95.8, 0.46, and 0.301. Each composite core collection represented the complete range of phenotypic and genetic variability of the crop including 19 BAPS clusters. This is the first report describing development of core collections in safflower using molecular marker data with phenotypic values and geographical distribution. These core collections will facilitate identification of genetic determinants of trait variability and effective utilization of the prevalent diversity in crop improvement programs.

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