The NIN-LIKE PROTEIN (NLP) family of transcription factors were identified as nitrate-responsive ciselement (NRE)-binding proteins, which function as transcriptional activators in the nitrate-regulated expression of downstream genes. this study was aimed at genome-wide analysis of NLP gene family in rice and the expression profiling of NLPs in response to nitrogen (N) supply and deficiency in rice genotypes with contrasting N use efficiency (NUE). Based on in silico analysis, 6 NLP genes (including alternative splice forms 11 NLPs) were identified from rice. Expression of NLPs was promoted by nitrate supply as well as N deficiency (NLP1, NLP3, NLP4 and NLP5). Four rice genotypes APO (high NUE under sufficient N), IR83929-B-B-291-3-1-1 (IR-3-1-1), Nerica-L-42 (NL-42) (High NUE at low N), and Pusa Basmati 1 (PB1, low NUE) to correlate traits governing NUE and expression of NLPs. Analysis of rate of nitrate uptake and expression of N assimilatory and uptake genes established that IR-3-1-1 has high uptake and assimilation efficiency, translating into high NUE, whereas PB1 is efficient in uptake only when N availability is high. Along with the transcriptional upregulation of NLPs, genotype IR-3-1-1, displayed highest expression of OsNRT1.1B gene, the closest rice homologue of nitrate transceptor AtNRT1.1 and plays major role in nitrate uptake, translocation and signaling in rice. The results showed that high NUE rice genotypes has both high Nitrogen uptake efficiency (NUpE) and Nitrogen utilization efficiency (NUtE), resulting from the effective and coordinated signal transduction network involving the rice homologue of nitrate transceptor OsNRT1.1B, the probable primary nitrate response (PNR) regulator OsNLP1 and the master response regulator OsNLP3, a homologue of AtNLP6/7. Nitrogen (N) is an essential nutrient and major component of proteins, chlorophyll, nucleotides and plant hormones, and therefore has immense role in determining plant growth and economic yield 1,2. In order to meet the food demand of ever-growing human population, enormous amounts of N fertilizers are applied inorder to tap the maximum crop yield potential worldwide 3. The global demand for N fertilizers in 2014 was 1.13 M tonnes and is projected to grow at approximately 1.4% per year, reaching 1.22 M tonnes by 2020 4. On the other hand, around 50% of the applied N fertilizer is lost to the environment depending on the cropping conditions and plant species. The loss of fertilizer N results in contamination of soil water and water bodies and production of nitrogenous greenhouse gases like nitrous oxide (N 2 O) which has high global warming potential 5. Nitrogen use efficiency (NUE) of rice is particularly low (around 40%), though genetic variation for the trait has been reported 6. Consequently, there is an impending requirement to improve the NUE of rice to maintain the steadiness of high crop yields visa vis low N fertilizer inputs 7. Transgenic manipulation is one of the potent way to achieve the current demand for high NUE, which necessitates...

Salt overly sensitive (SOS) pathway genes, SOS1 (plasma membrane Na ? /H ? antiporter), SOS2 (CBL interacting protein kinase 24), and SOS3 (calcineurin B like protein 4) are associated with active efflux of toxic sodium ions (Na ? ) from cytosol and thus confer salinity tolerance in glycophytic plants such as Arabidopsis. The role of SOS pathway genes SOS2 and SOS3 in salinity tolerance of wheat is rarely studied. One-month-old seedlings of three bread wheat genotypes namely, HD 2009, HD2687 and Kharchia 65 were imposed with two levels of salinity stress (100 and 200 mM NaCl) for 30 days duration. Based on the physiological parameters, genotype Kharchia 65 was highly tolerant, HD 2009 was moderately tolerant and HD 2687 was sensitive to salinity stress. Tolerant genotypes accumulated lesser amount of Na ? in root, stem and leaf tissues. Transcript abundance of SOS1, SOS2 and SOS3 genes was significantly higher in salt tolerant genotypes under long-term salinity and correlated with improved sodium exclusion, and higher potassium/sodium (K ? /Na ? ) ratio. Expression levels of genes involved in vacuolar partitioning of Na ? , NHX1 (vacuolar Na ? /H ? antiporter) and VP1 (Vacuolar pyrophosphatase) were also higher in salt tolerant wheat genotypes under 200 mM NaCl stress. Partial coding sequences of SOS1, SOS2, SOS3, NHX1 and VP1 genes were cloned and sequenced from the above mentioned three wheat genotypes. The results in the present study demonstrated that SOS pathway of ion homeostasis under salinity stress is conserved across species.Keywords Potassium Á Salinity stress Á SOS Á Sodium Á Vacuolar antiporter Á Wheat Communicated by P. Sowinski. Electronic supplementary materialThe online version of this article (

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Bread wheat (Triticum aestivum L.; Ta) is the staple cereal crop for the majority of the world’s population. Leaf rust disease caused by the obligate fungal pathogen, Puccinia triticina L., is a biotrophic pathogen causing significant economic yield damage. The alteration in the redox homeostasis of the cell caused by various kinds of reactive oxygen species (ROS) and reactive nitrogen species (RNS) in response to pathogenic infections is controlled by redox regulators. Thioredoxin (Trx) is one of the redox regulators with low molecular weight and is thermostable. Through a genome-wide approach, forty-two (42) wheat Trx genes (TaTrx) were identified across the wheat chromosome groups A, B, and D genomes containing 12, 16, and 14 Trx genes, respectively. Based on in silico expression analysis, 15 TaTrx genes were selected and utilized for further experimentation. These 15 genes were clustered into six groups by phylogenetic analysis. MicroRNA (miRNA) target analysis revealed eight different miRNA-targeted TaTrx genes. Protein–protein interaction (PPI) analysis showed TaTrx proteins interact with thioredoxin reductase, peroxiredoxin, and uncharacterized proteins. Expression profiles resulting from quantitative real-time PCR (qRT-PCR) revealed four TaTrx genes (TaTrx11-5A, TaTrx13-5B, TaTrx14-5D, and TaTrx15-3B) were significantly induced in response to leaf rust infection. Localization of ROS and its content estimation and an assay of antioxidant enzymes and expression analysis suggested that Trx have been involved in ROS homeostasis at span 24HAI-72HAI during the leaf rust resistance.

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Sugar beet is a salt-tolerant crop that can be explored for crop production in degraded saline soils. Seeds of multigerm genotypes LKC-2006 (susceptible) and LKC-HB (tolerant) were grown in 150 mM NaCl, from germination to 60 days after sowing, to decipher the mechanism of salinity tolerance at the vegetative stage.The biomass of the root and leaf were maintained in the tolerant genotype, LKC-HB, under saline conditions. Na + /K + ratios were similar in roots and leaves of LKC-HB, with lower values under salinity compared to LKC 2006. Infrared temperatures were 0.96 C lower in LKC-HB than in LKC-2006, which helped regulate the leaf water status under stressed conditions. Pulse-chase experiment showed that 14 C photosynthate was preferentially allocated towards the development of new leaves in the tolerant genotype. The sugar profile of leaves and roots showed accumulation of raffinose in leaves of LKC-HB, indicating a plausible role in imparting salinity tolerance by serving as an osmolyte or scavenger. The molecular analysis of the genes responsible for raffinose synthesis revealed an 18-fold increase in the expression of BvRS2 in the tolerant genotype, suggesting its involvement in raffinose synthesis. Our study accentuated that raffinose accumulation in leaves is vital for inducing salinity tolerance and maintenance of shoot dry weight in sugar beet.

Wheat is a major staple food crop worldwide contributing approximately 20% of total protein consumed by mankind. The nitrogen and protein concentration of wheat crop and grain often decline as a result of exposure of the crop to elevated CO (EC). The changes in nitrogen (N) assimilation, root system architecture, and nitric oxide (NO)-mediated N signaling and expression of genes involved in N assimilation and high affinity nitrate uptake were examined in response to different nitrate levels and EC in wheat. Activity of enzyme nitrate reductase (NRA) was downregulated under EC both in leaf and root tissues. Plants grown under EC displayed enhanced production of NO and more so when nitrate supply was high. Based on exogenous supply of NO, inhibitors of NO production, and NO scavenger, regulatory role of NO on EC mediated changes in root morphology and NRA was revealed. The enhanced NO production under EC and high N levels negatively regulated the transcript abundance of NR and high affinity nitrate transporters (HATS).