Browsing by Author "Sharmila Singh"

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Auxin signaling modulates LATERAL ROOT PRIMORDIUM1 (LRP1) expression during lateral root development in Arabidopsis
(Blackwell Publishing Ltd, 2020) Sharmila Singh; Sandeep Yadav; Alka Singh; Mahima Mahima; Archita Singh; Vibhav Gautam; Ananda K. Sarkar
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 the SHORT INTERNODES/STYLISH (SHI/STY) family, was identified as an auxin-inducible gene. The precise developmental role and molecular regulation of LRP1 in root development remain to be understood. Here we show that LRP1 is expressed in all stages of LR development, besides the 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 emerging LRs of slr-1 and arf7arf19 mutants roots. NPA treatment studies showed that LRP1 acts after LR founder cell specification and asymmetric division during LR development. Overexpression of LRP1 (LRP1 OE) showed an increased number of LR primordia (LRP) at stages 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 the increased accumulation of endogenous auxin in LRP1 OE roots. LRP1 interacts with SHI, STY1, SRS3, SRS6 and SRS7 proteins of the SHI/STY family, indicating their possible redundant role during root development. Our results suggested 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. © 2019 The Authors The Plant Journal © 2019 John Wiley & Sons Ltd
Conserved LBL1-ta-siRNA and miR165/166-RLD1/2 modules regulate root development in maize
(Company of Biologists Ltd, 2021) Vibhav Gautam; Archita Singh; Sandeep Yadav; Sharmila Singh; Pramod Kumar; Shabari Sarkar Das; Ananda K. Sarkar
Root system architecture and anatomy of monocotyledonous maize is significantly different from dicotyledonous model Arabidopsis. The molecular role of non-coding RNA (ncRNA) is poorly understood in maize root development. Here, we address the role of LEAFBLADELESS1 (LBL1), a component of maize trans-acting short-interfering RNA (ta-siRNA), in maize root development. We report that root growth, anatomical patterning, and the number of lateral roots (LRs), monocot-specific crown roots (CRs) and seminal roots (SRs) are significantly affected in lbl1-rgd1 mutant, which is defective in production of ta-siRNA, including tasiR-ARF that targets AUXIN RESPONSE FACTOR3 (ARF3) in maize. Altered accumulation and distribution of auxin, due to differential expression of auxin biosynthesis and transporter genes, created an imbalance in auxin signalling. Altered expression of microRNA165/166 (miR165/166) and its targets, ROLLED1 and ROLLED2 (RLD1/2), contributed to the changes in lbl1-rgd1 root growth and vascular patterning, as was evident by the altered root phenotype of Rld1-O semi-dominant mutant. Thus, LBL1/tasiRNA module regulates root development, possibly by affecting auxin distribution and signalling, in crosstalk with miR165/166-RLD1/2 module. We further show that ZmLBL1 and its Arabidopsis homologue AtSGS3 proteins are functionally conserved. © 2021. Published by The Company of Biologists Ltd
Whole mount in situ localization of miRNAs and target mRNA transcripts in plants
(Springer Verlag, 2019) Vibhav Gautam; Archita Singh; Swati Verma; Sharmila Singh; Sourav Chatterjee; Ananda K. Sarkar
The functional characterization of miRNAs often involves understanding of their spatiotemporal expression, which mostly relies on reporter-based or in situ hybridization studies. The available in situ localization methods follow separate protocols for pre-hybridization, hybridization, post-hybridization, and detection steps for both miRNA and mRNA transcripts in plants. In this study, we present a single method which can be used for whole mount in situ localization of both miRNAs and mRNAs in different plant tissues. Our modified method provides enhanced sensitivity for the localization of miRNA and their target transcripts. Consequently, a less laborious, time-saving, economic and efficient method has been proposed by the modification of pre-hybridization, hybridization, post-hybridization and detection steps. © 2019, King Abdulaziz City for Science and Technology.