Browsing by Author "Shukla, Brihaspati Narayan"

Now showing 1 - 3 of 3

Arabidopsis target of rapamycin coordinates with transcriptional and epigenetic machinery to regulate thermotolerance
(Frontiers Media S.A., 2021) Sharma, Mohan; Jamsheer, K.M.; Shukla, Brihaspati Narayan; Sharma, Manvi; Awasthi, Prakhar; Mahtha, Sanjeet Kumar; Yadav, Gitanjali; Laxmi, Ashverya
Global warming exhibits profound effects on plant fitness and productivity. To withstand stress, plants sacrifice their growth and activate protective stress responses for ensuring survival. However, the switch between growth and stress is largely elusive. In the past decade, the role of the target of rapamycin (TOR) linking energy and stress signalling is emerging. Here, we have identified an important role of Glucose (Glc)-TOR signalling in plant adaptation to heat stress (HS). Glc via TOR governs the transcriptome reprogramming of a large number of genes involved in heat stress protection. Downstream to Glc-TOR, the E2Fa signalling module regulates the transcription of heat shock factors through direct recruitment of E2Fa onto their promoter regions. Also, Glc epigenetically regulates the transcription of core HS signalling genes in a TOR-dependent manner. TOR acts in concert with p300/CREB HISTONE ACETYLTRANSFERASE1 (HAC1) and dictates the epigenetic landscape of HS loci to regulate thermotolerance. Arabidopsis plants defective in TOR and HAC1 exhibited reduced thermotolerance with a decrease in the expression of core HS signalling genes. Together, our findings reveal a mechanistic framework in which Glc-TOR signalling through different modules integrates stress and energy signalling to regulate thermotolerance.
FCS-like zinc finger 6 and 10 repress SnRK1 signalling in Arabidopsis
(John Wiley & Sons, 2018) Jamsheer, Muhammed K.; Sharma, Manvi; Singh, Dhriti; Mannully, Chanchal Thomas; Jindal, Sunita; Shukla, Brihaspati Narayan; Laxmi, Ashverya
SNF1-Related Protein Kinase 1 (SnRK1) is a central regulator of plant growth during energy starvation. The FCS-Like Zinc finger (FLZ) proteins are recently identified adaptor proteins which facilitate the interaction of SnRK1 with other proteins. In this study, we identified that two starvation-induced FLZ genes, FLZ6 and FLZ10, work as repressors of SnRK1 signalling. The reduced expression of these genes resulted in an increase in the level of SnRK1α1, which is the major catalytic subunit of SnRK1. This resulted in a concomitant increase in the phosphorylated protein and SnRK1 activity in the flz6 and flz10 mutants. FLZ6 and FLZ10 specifically interact with SnRK1α subunits in the cytoplasmic foci which colocalized with the endoplasmic reticulum. In physiological assays, similar to SnRK1α1 overexpression line, flz mutants showed compromised growth. Further, the growth promotion in response to favourable growth conditions was found to be attenuated in the mutants. The enhanced SnRK1 activity in the mutants resulted in a reduction in the level of phosphorylated RIBOSOMAL S6 KINASE and the expression of E2Fa and its targets indicating that TARGET OF RAPAMYCIN-dependent promotion of protein synthesis and cell cycle progression is impaired. Taken together, this study uncovers a plant-specific modulation of SnRK1 signalling.
Understanding the intricate web of phytohormone signalling in modulating root system architecture
(MDPI AG, 2021) Sharma, Manvi; Singh, Dhriti; Saksena, Harshita B.; Sharma, Mohan; Tiwari, Archna; Awasthi, Prakhar; Botta, Halidev Krishna; Shukla, Brihaspati Narayan; Laxmi, Ashverya
Root system architecture (RSA) is an important developmental and agronomic trait that is regulated by various physical factors such as nutrients, water, microbes, gravity, and soil compaction as well as hormone-mediated pathways. Phytohormones act as internal mediators between soil and RSA to influence various events of root development, starting from organogenesis to the formation of higher order lateral roots (LRs) through diverse mechanisms. Apart from interaction with the external cues, root development also relies on the complex web of interaction among phytohormones to exhibit synergistic or antagonistic effects to improve crop performance. However, there are considerable gaps in understanding the interaction of these hormonal networks during various aspects of root development. In this review, we elucidate the role of different hormones to modulate a common phenotypic output, such as RSA in Arabidopsis and crop plants, and discuss future perspectives to channel vast information on root development to modulate RSA components.