Browsing by Author "Jamsheer, K. Muhammed"

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Balancing growth and defense: Role of target of rapamycin and SNF1-related protein kinase 1 in stress signaling in plants
(John Wiley & Sons, 2021) Sharma, Mohan; Jamsheer, K. Muhammed; Saksena, Harshita B.; Jindal, Sunita; Sharma, Manvi; Singh, Dhriti; Tiwari, Archna; Awasthi, Prakhar; Laxmi, Ashverya
Plants have to maintain the growth and at the same time need to be vigilant about the imminent threat such as pathogen attack and unfavorable growth conditions. It is been observed that the energy status of the plant is an important determinant of the response to stress factors. The Target Of Rapamycin (TOR) and SNF1-Related Protein Kinase 1 (SnRK1) are serine/threonine kinases that originated early in the eukaryotic evolution, work as energy gauges in all eukaryotic lineages. During favorable growth conditions, the nutrient abundance activates TOR, which promotes growth through activation of general protein translation and cell cycle progression. The stress conditions can severely limit energy production, which can activate SnRK1 signaling. By inhibiting TOR kinase and through other effector proteins, the SnRK1 pathway enables the plants to survive in unfavorable growth conditions. The past decade opened a floodgate of studies regarding TOR and SnRK1 interaction regulating growth-defense trade-offs and stress mitigation. This also opened avenues for the utilization of these pathways for crop improvement. This chapter will succinctly summarize the current knowledge in this field and discuss the future direction of research.
Jasmonic acid coordinates with light, glucose and auxin signalling in regulating branching angle of Arabidopsis lateral roots
(John Wiley & Sons, 2022) Sharma, Manvi; Sharma, Mohan; Jamsheer, K. Muhammed; Laxmi, Ashverya
The role of jasmonates (JAs) in primary root growth and development and in plant response to external stimuli is already known. However, its role in lateral root (LR) development remains to be explored. Our work identified methyl jasmonate (MeJA) as a key phytohormone in determining the branching angle of Arabidopsis LRs. MeJA inclines the LRs to a more vertical orientation, which was dependent on the canonical JAR1-COI1-MYC2,3,4 signalling. Our work also highlights the dual roles of light in governing LR angle. Light signalling enhances JA biosynthesis, leading to erect root architecture; whereas, glucose (Glc) induces wider branching angles. Combining physiological and molecular assays, we revealed that Glc antagonizes the MeJA response via TARGET OF RAPAMYCIN (TOR) signalling. Moreover, physiological assays using auxin mutants, MYC2-mediated transcriptional activation of LAZY2, LAZY4 and auxin biosynthetic gene CYP79B2,and asymmetric distribution of DR5::GFP and PIN2::GFP pinpointed the role of an intact auxin mechanism required by MeJA for vertical growth of LRs. We also demonstrated that light perception and signalling are indispensable for inducing vertical angles by MeJA. Thus, our investigation highlights antagonism between light and Glc signalling and how they interact with JA-auxin signals to optimize the branching angle of LRs.