Browsing by Author "Mahima"

Now showing 1 - 3 of 3

Auxin signaling modulates LATERAL ROOT PRIMORDIUM1 (LRP1) expression during lateral root development in Arabidopsis
(John Wiley & Sons, 2020) Singh, Sharmila; Yadav, Sandeep; Singh, Alka; Mahima; Singh, Archita; Gautam, Vibhav; Sarkar, Ananda K.
Auxin signaling mediated by various Auxin/Indole-3-Acetic Acid (Aux/IAAs) and AUXIN RESPONSE FACTORs (ARFs) regulate lateral root (LR) development by controlling the expression of downstream genes. LATERAL ROOT PRIMORDIUM1 (LRP1), a member of SHORT INTERNODES/STYLISH (SHI/STY) family, was identified as an auxin inducible gene. Precise developmental role and molecular regulation of LRP1 in root development remains to be understood. Here we show that LRP1 is expressed in all stages of LR development, besides primary root. The expression of LRP1 is regulated by histone deacetylation in an auxin dependent manner. Our genetic interaction studies showed that LRP1 acts downstream of auxin responsive Aux/IAAs-ARFs modules during LR development. We showed that auxin mediated induction of LRP1 is lost in slr-1 and arf7arf19 mutants roots. NPA treatment studies showed that LRP1 acts after LR founder cell specification and asymmetric division. Overexpression of LRP1 (LRP1 OE) showed increased number of LRPs at stage I, IV and V, resulting in reduced emerged LR density, which suggests that it is involved in LRP development. Interestingly, LRP1 induced expression of YUC4, which is involved in auxin biosynthesis, contributes to increased accumulation of endogenous auxin in LRP1 OE roots. LRP1 interacts with SHI, STY1, SRS3 and SRS7 proteins of SHI/STY family indicating their possible redundant role during root development. Our results suggest that auxin and histone deacetylation affect LRP1 expression, and it acts downstream of LR forming auxin response modules to negatively regulate LRP development by modulating auxin homeostasis in Arabidopsis thaliana.
Role of chromatin modification and remodeling in stem cell regulation and meristem maintenance in Arabidopsis
(Oxford University Press, 2020) Singh, Sharmila; Singh, Alka; Singh, Archita; Mahima; Yadav, Sandeep; Bajaj, Ishita; Kumar, Shailendra; Jain, Ajay; Sarkar, Ananda K.
In higher plants, pluripotent stem cells reside in the specialized microenvironment called stem cell niches (SCNs) harbored at the shoot apical meristem (SAM) and root apical meristem (RAM), which give rise to the aerial and underground parts of a plant, respectively. The model plant Arabidopsis thaliana (Arabidopsis) has been extensively studied to decipher the intricate regulatory mechanisms involving some key transcriptions factors and phytohormones that play pivotal roles in stem cell homeostasis, meristem maintenance, and organ formation. However, there is increasing evidence to show the epigenetic regulation of the chromatin architecture, gene expression exerting an influence on an innate balance between the self-renewal of stem cells, and differentiation of the progeny cells to a specific tissue type or organ. Post-translational histone modifications, ATP-dependent chromatin remodeling, and chromatin assembly/ disassembly are some of the key features involved in the modulation of chromatin architecture. Here, we discuss the major epigenetic regulators and illustrate their roles in the regulation of stem cell activity, meristem maintenance, and related organ patterning in Arabidopsis.
Role of miRNAs in root development of model plant Arabidopsis thaliana
(Springer, 2017) Gautam, Vibhav; Singh, Archita; Verma, Swati; Kumar, Ashutosh; Kumar, Pramod; Mahima; Singh, Sharmila; Mishra, Vishnu; Sarkar, Ananda K.
The molecular regulation of root development is relatively well studied in model plant Arabidopsis as compared to other plants. Besides phytohormones, transcription factors and environmental factors, other important regulators which have recently been shown to play crucial roles in controlling root development are the non-coding RNAs. Small non-coding RNAs of 21–24 nt length (miRNAs and ta-siRNAs) regulate various aspects of plant development by negatively regulating their target genes through transcript cleavage or translational inhibition. In recent past the microRNA-mediated regulation of root development has drawn significant interest in the area of plant research. Several reports have highlighted the role of many miRNAs and ta-siRNAs in root growth, vascular patterning, lateral root (LR) formation and elongation, and adventitious root development, Phytohormones like auxin, cytokinin and environmental factors like light, abiotic and biotic stresses, and nutrient availability influence many miRNA-mediated regulation of root growth and branching. In current review, we summarize the recent advances made in understanding the miRNA-mediated regulation of root development in the model plant Arabidopsis thaliana. The molecular crosstalk between different miRNAs, ta-siRNAs, and concerned target genes that regulate root growth and branching have been addressed.