Correction to: Identification and validation of reference genes in vetiver (Chrysopogon zizanioides) root transcriptome.

[This corrects the article DOI: 10.1007/s12298-023-01315-7.].

Identification and validation of reference genes in vetiver (Chrysopogon zizanioides) root transcriptome.

Vetiver [Vetiveria zizanioides (L.) Roberty] is a perennial C-4 grass traditionally valued for its aromatic roots/root essential oil. Owing to its deep penetrating web-forming roots, the grass is now widely used across the globe for phytoremediation and the conservation of soil and water. This study has used the transcriptome data of vetiver roots in its two distinct geographic morphotypes (North Indian type A and South Indian type B) for reference gene(s) identification. Further, validation of reference genes using various abiotic stresses such as heat, cold, salt, and drought was carried out. The de novo assembly based on differential genes analysis gave 1,36,824 genes (PRJNA292937). Statistical tests like RefFinder, NormFinder, BestKeeper, geNorm, and Delta-Ct software were applied on 346 selected contigs. Eleven selected genes viz., GAPs, UBE2W, RP, OSCam2, MUB, RPS, Core histone 1, Core histone 2, SAMS, GRCWSP, PLDCP along with Actin were used for qRT-PCR analysis. Finally, the study identified the five best reference genes GAPs, OsCam2, MUB, Core histone 1, and SAMS along with Actin. The two optimal reference genes SAMS and Core histone 1 were identified with the help of qbase + software. The findings of the present analyses have value in the identification of suitable reference gene(s) in transcriptomic and molecular data analysis concerning various phenotypes related to abiotic stress and developmental aspects, as well as a quality control measure in gene expression experiments. Identifying reference genes in vetiver appears important as it allows for accurate normalization of gene expression data in qRT-PCR experiments. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01315-7.

Comprehensive illustration of transcriptomic and proteomic dataset for mitigation of arsenic toxicity in rice (Oryza sativa L.) by microbial consortium.

The present article represents the data for analysis of microbial consortium (P.putida+C.vulgaris) mediated amelioration of arsenic toxicity in rice plant. In the current study the transcriptome profiling of treated rice root and shoot was performed by illumina sequencing (Platform 2000). To process the reads and to analyse differential gene expression, Fastxtoolkit, NGSQCtoolkit, Bowtie 2 (version 2.1.0), Tophat program (version 2.0.8), Cufflinks and Cuffdiff programs were used. For Proteome profiling, total soluble proteins in shoot of rice plant among different treatments were extracted and separated by 2D poly acrylamide gel electrophoresis (PAGE) and then proteins were identified with the help of MALDI-TOF/TOF. In gel based method of protein identification, the isoelectric focusing machine (IPGphor system,Bio-Rad USA), gel unit (SDS-PAGE) and MALDI-TOF/TOF (4800 proteomic analyzer Applied Biosystem, USA) were used for successful separation and positive identification of proteins. To check the differential abundance of proteins among different treatments, PDQuest software was used for data analysis. For protein identification, Mascot search engine (http://www.matrixscience.com) using NCBIprot/SwissProt databases of rice was used. The analyzed data inferred comprehensive picture of key genes and their respective proteins involved in microbial consortium mediated improved plant growth and amelioration of As induced phyto-toxicity in rice. For the more comprehensive information of data, the related full-length article entitled "Microbial consortium mediated growth promotion and Arsenic reduction in Rice: An integrated transcriptome and proteome profiling" may be accessed.

Metastatic malignant peripheral nerve sheath tumor. A diagnostic surprise.

Malignant peripheral nerve sheath tumours (MPNSTs) are rare soft tissue tumors that arise from pre-existing plexiform neurofibromas or within a normal peripheral nerve. They are aggressive tumors with high rates of recurrence and distant metastases, the most common sites of metastasis being the lung followed by bone. A 46 year old gentleman presented with breathlessness and chest pain three years after post amputation of left thumb for an ulcerative growth. CECT thorax showed a left upper lobe mass with pleural and pericardial effusion. Within a month of presentation he worsened and succumbed to the disease. Antemortem biopsy of the left hand ulcerative growth showed features suggestive of malignant peripheral nerve sheath tumour- epithelioid variant and post mortem liver and lung biopsy showed metastasis of MPNST. The diagnosis was a malignant peripheral nerve sheath tumor with lung, liver and cardiac metastasis. This case report aims to highlight the importance of upfront aggressive multimodality local therapy for achieving local disease control in patients presenting with localised MPNST and regular follow up for early detection of relapse and metastasis.

Root system architecture, physiological analysis and dynamic transcriptomics unravel the drought-responsive traits in rice genotypes.

Drought is the major abiotic factors that limit crop productivity worldwide. To withstand stress conditions, plants alter numerous mechanisms for adaption and tolerance. Therefore, in the present study, 106 rice varieties were screened for drought tolerance phenotype via exposing different concentrations of polyethylene glycol 6000 (PEG) in the hydroponic nutrient medium at the time interval of 1, 3, and 7 days to evaluate the changes in their root system architecture. Further, based on root phenotype obtained after PEG-induced drought, two contrasting varieties drought-tolerant Heena and -sensitive Kiran were selected to study transcriptional and physiological alterations at the same stress durations. Physiological parameters (photosynthesis rate, stomatal conductance, transpiration), and non-enzymatic antioxidants (carotenoids, anthocyanins, total phenol content) production indicated better performance of Heena than Kiran. Comparatively higher accumulation of carotenoid and anthocyanin content and the increased photosynthetic rate was also observed in Heena. Root morphology (length, numbers of root hairs, seminal roots and adventitious roots) and anatomical data (lignin deposition, xylem area) enable tolerant variety Heena to better maintain membrane integrity and relative water content, which also contribute to comparatively higher biomass accumulation in Heena under drought. In transcriptome profiling, significant drought stress-associated differentially expressed genes (DEGs) were identified in both the varieties. A total of 1033 and 936 uniquely upregulated DEGs were found in Heena and Kiran respectively. The significant modulation of DEGs that were mainly associated with phytohormone signaling, stress-responsive genes (LEA, DREB), transcription factors (TFs) (AP2/ERF, MYB, WRKY, bHLH), and genes involved in photosynthesis and antioxidative mechanisms indicate better adaptive nature of Heena in stress tolerance. Additionally, the QTL-mapping analysis showed a very high number of DEGs associated with drought stress at AQHP069 QTL in Heena in comparison to Kiran which further distinguishes the drought-responsive traits at the chromosomal level in both the contrasting varieties. Overall, results support the higher capability of Heena over Kiran variety to induce numerous genes along with the development of better root architecture to endure drought stress.

Petal abscission in fragrant roses is associated with large scale differential regulation of the abscission zone transcriptome.

Flowers of fragrant roses such as Rosa bourboniana are ethylene-sensitive and undergo rapid petal abscission while hybrid roses show reduced ethylene sensitivity and delayed abscission. To understand the molecular mechanism underlying these differences, a comparative transcriptome of petal abscission zones (AZ) of 0 h and 8 h ethylene-treated flowers from R. bourboniana was performed. Differential regulation of 3700 genes (1518 up, 2182 down) representing 8.5% of the AZ transcriptome was observed between 0 and 8 h ethylene-treated R. bourboniana petal AZ. Abscission was associated with large scale up-regulation of the ethylene pathway but prominent suppression of the JA, auxin and light-regulated pathways. Regulatory genes encoding kinases/phosphatases/F-box proteins and transcription factors formed the major group undergoing differential regulation besides genes for transporters, wall modification, defense and phenylpropanoid pathways. Further comparisons with ethylene-treated petals of R. bourboniana and 8 h ethylene-treated AZ (R. hybrida) identified a core set of 255 genes uniquely regulated by ethylene in R. bourboniana AZ. Almost 23% of these encoded regulatory proteins largely conserved with Arabidopsis AZ components. Most of these were up-regulated while an entire set of photosystem genes was prominently down-regulated. The studies provide important information on regulation of petal abscission in roses.

Over-expression of rice R1-type MYB transcription factor confers different abiotic stress tolerance in transgenic Arabidopsis.

Among various abiotic stresses, water deficit hit the first in the list followed by heavy metal stresses as a serious environmental growth-limiting factor that restricts the global crop yield. Molecular approaches will help us to trace key regulators which are involved in stress-related phenomenon to enhance crop productivity. The present study functionally characterized one of the key regulators, OsMYB-R1 in Arabidopsis. Phylogenetic analyses indicated that OsMYB-R1 had a close relationship with Sorghum bicolour and Zea mays. Ectopic expression of OsMYB-R1 in Arabidopsis resulted in improved tolerance to PEG/drought and chromium stress in addition to conferring no tolerance to salinity stress. Further RNA seq. data revealed that OsMYB-R1 regulates the expression of key genes that improve the root architecture and maintain the cellular homeostasis of transgenic lines through an efficient anti-oxidant system. It also reveals the differential gene expression of stress-responsive and hormone-responsive genes, which indicate the intricate network of defense regulatory machinery activated in transgenic lines. Additionally, salicylic acid (SA) plays a significant role in promoting the growth of the OsMYB-R1 over-expressing plants and increased GUS intensity in SA treated OsMYB-R1 promoter plants demonstrate the explicit role of SA signaling in overcoming stress tolerance. Whereas no significant change was observed in OsMYB-R1 over-expressing plants after ABA and MeJA treatment. Overall, OsMYB-R1 is a promising gene resource for improving abiotic stress tolerance in other crops, especially in dicotyledon plants.

Auxin-salicylic acid cross-talk ameliorates OsMYB-R1 mediated defense towards heavy metal, drought and fungal stress.

The MYB TF family is an immensely large and functionally diverse class of proteins involved in the regulation of cell cycle, cell morphogenesis to stress signaling mechanism. The present study deciphered the hormonal cross-talk of wound inducible and stress-responsive OsMYB-R1 transcription factor in combating abiotic [Cr(VI) and drought/PEG] as well as biotic (Rhizoctonia solani) stress. OsMYB-R1 over-expressing rice transgenics exhibit a significant increase in lateral roots, which may be associated with increased tolerance under Cr(VI) and drought exposure. In contrast, its loss-of-function reduces stress tolerance. Higher auxin accumulation in the OsMYB-R1 over-expressed lines further strengthens the protective role of lateral roots under stress conditions. RNA-seq. data reveals over-representation of salicylic acid signaling molecule calcium-dependent protein kinases, which probably activate the stress-responsive downstream genes (Peroxidases, Glutathione S-transferases, Osmotins, Heat Shock Proteins, Pathogenesis Related-Proteins). Enzymatic studies further confirm OsMYB-R1 mediated robust antioxidant system as catalase, guaiacol peroxidase and superoxide dismutase activities were found to be increased in the over-expressed lines. Our results suggest that OsMYB-R1 is part of a complex network of transcription factors controlling the cross-talk of auxin and salicylic acid signaling and other genes in response to multiple stresses by modifying molecular signaling, internal cellular homeostasis and root morphology.

Transcriptome and proteome analyses reveal selenium mediated amelioration of arsenic toxicity in rice (Oryza sativa L.).

Arsenic (As), a chronic poison and non-threshold carcinogen, is a food chain contaminant in rice, posing yield losses as well as serious health risks. Selenium (Se), a trace element, is a known antagonist of As toxicity. In present study, RNA seq. and proteome profiling, along with morphological analyses were performed to explore molecular cross-talk involved in Se mediated As stress amelioration. The repair of As induced structural deformities involving disintegration of cell wall and membranes were observed upon Se supplementation. The expression of As transporter genes viz., NIP1;1, NIP2;1, ABCG5, NRAMP1, NRAMP5, TIP2;2 as well as sulfate transporters, SULTR3;1 and SULTR3;6, were higher in As + Se compared to As alone exposure, which resulted in reduced As accumulation and toxicity. The higher expression of regulatory elements like AUX/IAA, WRKY and MYB TFs during As + Se exposure was also observed. The up-regulation of GST, PRX and GRX during As + Se exposure confirmed the amelioration of As induced oxidative stress. The abundance of proteins involved in photosynthesis, energy metabolism, transport, signaling and ROS homeostasis were found higher in As + Se than in As alone exposure. Overall, present study identified Se responsive pathways, genes and proteins involved to cope-up with As toxicity in rice.

Identification and expression analysis of conserved microRNAs during short and prolonged chromium stress in rice (Oryza sativa).

MicroRNAs (miRNAs) are one of the most critical epigenetic regulators of gene expression which modulate a spectrum of development and defence response processes in plants. Chromium (Cr) contamination in rice imposes a serious concern to human health as rice is used as staple food throughout the world. Although several studies have established the differential response of miRNAs in rice during heavy metal (arsenic, cadmium) and heat or cold stress, no report is available about the response of miRNAs during Cr stress. In the present study, we identified 512 and 568 known miRNAs from Cr treated and untreated samples, respectively. Expression analysis revealed that 13 conserved miRNAs (miR156, miR159, miR160, miR166, miR169, miR171, miR396, miR397, miR408, miR444, miR1883, miR2877, miR5072) depicted preferential up- or down-regulation (> 4-fold change; P value < 0.05). Target gene prediction of differentially expressed miRNAs and their functional annotation suggested the important role of miRNAs in defence and detoxification of Cr though ATP-binding cassette transporters (ABC transporters), transcription factors, heat shock proteins, auxin response, and metal ion transport. Real-time PCR analysis validated the differential expression of selected miRNAs and their putative target genes. In conclusion, our study identifies and predicts miRNA-mediated regulation of signalling pathway in rice during Cr stress.

Transcriptional alterations reveal Bacillus amyloliquefaciens-rice cooperation under salt stress.

The Bacillus amyloliquefaciens-SN13 and model crop rice (Oryza sativa) were chosen to understand the complex regulatory networks that govern plant-PGPR interaction under salt stress. During stress, inoculation with SN13 significantly increased biomass, relative water content, proline and total soluble sugar in rice while decreased lipid peroxidation and electrolyte leakage. Extensive alterations in gene expression were also observed in rice root transcriptome under stress in the presence of SN13. Rhizobacteria induced changes in expression of a considerable number of photosynthesis, hormone, and stress-responsive genes, in addition to cell-wall and lipid metabolism-related genes under salt stress as compared to salt stress or SN13 inoculation alone, indicating its potential role in reducing the harmful effects of salinity. To validate RNA-seq data, qRT-PCR was performed for selected differentially expressed genes representing various functional categories including metabolism, regulation, stress-response, and transporters. Results indicate qualitative and quantitative differences between roots responses to SN13 under stressed and unstressed conditions. Functional expressions of OsNAM and OsGRAM in yeast showed enhanced tolerance to various abiotic stresses, indicating crucial SN13-rice interaction in imparting beneficial effects under stress. This is first detailed report on understanding molecular mechanism underlying beneficial plant-microbe interaction in any economically important model crop plant under abiotic stress.

Rice (Oryza sativa L.) tau class glutathione S-transferase (OsGSTU30) overexpression in Arabidopsis thaliana modulates a regulatory network leading to heavy metal and drought stress tolerance.

Glutathione S-transferases (GSTs) are well-known enzymes due to their role in detoxification of xenobiotic compounds. However, their biochemical action is still not so clear in imparting tolerance to several abiotic stresses in crop plants. In our previous study, we observed that rice tau class OsGSTU30 plays a significant role in the detoxification of Cr(vi). Interestingly, q-RT PCR analysis also revealed higher expression of OsGSTU30 under drought conditions. In this study, we characterize OsGSTU30 in response to drought as well as heavy metal [Cr(vi)] stresses through overexpression in Arabidopsis thaliana. Biochemical and physiological analyses revealed that OsGSTU30 overexpression lines have improved tolerance against both stresses as compared to wild-type plants. Kinetic analysis and molecular docking confirmed that OsGSTU30 enzyme possesses both GST as well as glutathione peroxidase (GPx) like activity. Differentially expressed stress-responsive genes were also identified by transcriptome analysis, involved in different biological pathways during abiotic stresses. These results suggest the signaling functions of OsGSTU30 apart from its catalytic activity during abiotic stress responses and can be further exploited for improving the stress tolerance in crops.

De novo assembly and characterization of root transcriptome in two distinct morphotypes of vetiver, Chrysopogon zizaniodes (L.) Roberty.

Vetiver, a perennial C4 grass, has long been known for its multifarious uses in perfumery, medicine and environmental protection. Two distinct vetiver morphotypes have been identified in India, i.e., A. North Indian type characterized by thick and smooth fast growing roots that produce superior quality of laevorotatory oil; and B. South Indian type with more number of thin and hairy roots that produce inferior quality of dextrorotatory oil. The two morphotypes were targeted for transcriptome analysis to understand the contribution of genetic background on oil quality and root morphology. Sample A showed enhanced activity of flavonoid and terpenoid biosynthesis related genes, i.e. ERF, MYB, bHLH, bZIP and WRKY. Interestingly, expression analysis revealed that the genes involved in sesquiterpene biosynthesis pathway were up regulated in Sample A. Moreover, some of the genes involved in mevalonate pathway of sesquiterpene biosynthesis were unique to Sample A. Our results also demonstrated several transcripts involved in root development and hormonal regulation being up regulated in Sample A. To validate gene expression results of RNA-seq data, 20 transcripts were validated by qRT-PCR experiment. The present study provided an important start point for further discovery of genes related to root oil quality in different ecotypes of vetiver.