Institutional Publications
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Item Conserved LBL1-ta-siRNA and miR165/166-RLD1/2 modules regulate root development in maize(The Company of Biologists, 2021) Gautam, Vibhav; Singh, Archita; Yadav, Sandeep; Singh, Sharmila; Kumar, Pramod; Das, Shabari Sarkar; Sarkar, Ananda K.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 the root growth, anatomical patterning, number of lateral roots (LRs) and 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 signaling. Altered expression of microRNA165/166 (miR165/166) and its targets ROLLED1/2 (RLD1/2) contributed to the changes in lbl1-rgd1 root growth and vascular patterning, as was evident by altered root phenotype of Rld1-O semi-dominant mutant. Thus, LBL1/ta-siRNA module regulates root development, possibly by affecting auxin distribution and signaling, in crosstalk with miR165/166-RLD1/2 module. We further showed that ZmLBL1 and its Arabidopsis homolog AtSGS3 proteins are functionally conserved.Item Sirtinol, a Sir2 protein inhibitor, affects stem cell maintenance and root development in Arabidopsis thaliana by modulating auxin-cytokinin signaling components(Nature Publishing Group, 2017) Singh, Sharmila; Singh, Alka; Yadav, Sandeep; Gautam, Vibhav; Singh, Archita; Sarkar, Ananda K.In Arabidopsis thaliana, besides several key transcription factors and chromatin modifiers, phytohormones auxin and cytokinin play pivotal role in shoot and root meristem maintenance, and lateral root (LR) development. Sirtinol, a chemical inhibitor of Sir2 proteins, is known to promote some auxin induced phenotypes in Arabidopsis. However, its effect on plant stem cell maintenance or organ formation remained unaddressed. Here we show that sirtinol affects meristem maintenance by altering the expression of key stem cell regulators, cell division and differentiation by modulating both auxin and cytokinin signaling in Arabidopsis thaliana. The expression of shoot stem cell niche related genes WUSCHEL (WUS) and CLAVATA3 (CLV3) was upregulated, whereas SHOOT MERISTEMLESS (STM) was downregulated in sirtinol treated seedlings. The expression level and domain of key root stem cell regulators PLETHORA (PLTs) and WUS-Related Homeobox 5 (WOX5) were altered in sirtinol treated roots. Sirtinol affects LR development by disturbing proper auxin transport and maxima formation, similar to 2,4-dichlorophenoxyacetic acid (2,4-D). Sirtinol also affects LR formation by altering cytokinin biosynthesis and signaling genes in roots. Therefore, sirtinol affects shoot and root growth, meristem maintenance and LR development by altering the expression of cytokinin-auxin signaling components, and regulators of stem cells, meristems, and LRs.
