Browsing by Author "Sharma, Tilak Raj"

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Dissecting the nutrient partitioning mechanism in rice grain using spatially resolved gene expression profiling
(Oxford University Press, 2021) Ram, Hasthi; Singh, Anmol; Katoch, Megha; Kaur, Ravneet; Sardar, Shaswati; Palia, Shubham; Satyam, Rohit; Sonah, Humira; Deshmukh, Rupesh; Pandey, Ajay Kumar; Gupta, Ishaan; Sharma, Tilak Raj
Rice, a staple food worldwide, contains varying amounts of nutrients in different grain tissues. The underlying molecular mechanism of such distinct nutrient partitioning remains poorly investigated. Here, an optimized rapid laser capture microdissection (LCM) approach was used to individually collect pericarp, aleurone, embryo and endosperm from grains 10 days after fertilization. Subsequent RNA-Seq analysis in these tissues identified 7760 differentially expressed genes. Analysis of promoter sequences of tissue-specific genes identified many known and novel cis-elements important for grain filling and seed development. Using the identified differentially expressed genes, comprehensive spatial gene expression pathways were built for accumulation of starch, proteins, lipids, and iron. The extensive transcriptomic analysis provided novel insights about nutrient partitioning mechanisms; for example, it revealed a gradient in seed storage protein accumulation across the four tissue types analysed. The analysis also revealed that the partitioning of various minerals, such as iron, is most likely regulated through transcriptional control of their transporters. We present the extensive analysis from this study as an interactive online tool that provides a much-needed resource for future functional genomics studies aimed to improve grain quality and seed development.
Dynamic role of aquaporin transport system under drought stress in plants
(Elsevier B.V., 2021) Shivaraj, SM; Sharma, Yogesh; Chaudhary, Juhi; Rajora, Nitika; Sharma, Shivani; Thakral, Vandana; Ram, Hasthi; Sonah, Humira; Singla-Pareek, Sneh L.; Sharma, Tilak Raj; Deshmukh, Rupesh
Prolonged soil moisture deficit poses major threat to plant survival. Plants have evolved to withstand such condition by maintaining water status through adoptive mechanisms. Such mechanisms include modulation of Aquaporins (AQPs) activity. The AQPs are small integral membrane proteins which facilitate water movement across the cells. This review summarizes the important regulatory mechanisms controlling the dynamics of AQP activity to fine tune the plant water status under the water deficit condition. Numerous studies have shown differential AQP expression under drought stress in plants. Among the known AQP subfamilies, members of plasma membrane intrinsic protein (PIP) and tonoplast intrinsic protein (TIP) showed most significant expression under drought condition. The activity, stability, and membrane targeting of these AQPs are known to be regulated at transcriptional as well as post-translational level. Drought induced transcription factors and hormones are also involved in direct or indirect transcriptional regulation. At post-translational level modifications such as phosphorylation, glycosylation, ubiquitination, gating and tetramerization play a role in regulation of the abundance and activity of AQP proteins. Understanding such regulatory mechanisms will help in exploration of AQPs to improve crop plants for sustainable agriculture under changing environmental conditions.
Nitric oxide and hydrogen sulfide crosstalk during heavy metal stress in plants
(John Wiley & Sons, 2020) Shivaraj, Sheelavanta Matha; Vats, Sanskriti; Bhat, Javid Akhter; Dhakte, Priyanka; Goyal, Vinod; Khatri, Praveen; Kumawat, Surbhi; Singh, Akshay; Prasad, Manoj; Sonah, Humira; Sharma, Tilak Raj; Deshmukh, Rupesh
Gases such as ethylene, hydrogen peroxide (H2O2), nitric oxide (NO), carbon monoxide (CO), and hydrogen sulfide (H2S) have been recognized as vital signaling molecules in plants and animals. Of these gasotransmitters, NO and H2S have recently gained momentum mainly because of their involvement in numerous cellular processes. It is therefore important to study their various attributes including their biosynthetic and signaling pathways. The present review provides an insight into various routes for the biosynthesis of NO and H2S as well as their signaling role in plant cells under different conditions, more particularly under heavy metal stress. Their beneficial roles in the plant's protection against abiotic and biotic stresses as well as their adverse effects have been addressed. This review describes how H2S and NO, being very small size molecules, can quickly pass through the cell membranes and triggers a multitude of responses to various factors, notably to various stress conditions like drought, heat, osmotic, heavy metal, and multiple biotic stresses. The versatile interactions between H2S and NO involved in the different molecular pathways have been discussed. In addition to the signaling role of H2S and NO, their direct role in post‐translational modifications is also considered. The information provided here will be helpful to better understand the multifaceted roles of H2S and NO in plants, particularly under stress conditions.