title: Sirtinol, a Sir2 protein inhibitor, affects stem cell maintenance and root development in Arabidopsis thaliana by modulating auxin-cytokinin signaling components.
abstract: 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.
authors.affiliation: National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067 India.
authors.forename: Sharmila
authors.initials: S
authors.lastname: Singh
authors.affiliation: National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067 India.
authors.forename: Alka
authors.initials: A
authors.lastname: Singh
authors.affiliation: National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067 India.
authors.forename: Sandeep
authors.initials: S
authors.lastname: Yadav
authors.affiliation: National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067 India.
authors.forename: Vibhav
authors.initials: V
authors.lastname: Gautam
authors.affiliation: National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067 India.
authors.forename: Archita
authors.initials: A
authors.lastname: Singh
authors.affiliation: National Institute of Plant Genome Research, Aruna Asaf Ali Marg, New Delhi 110067 India.
authors.forename: Ananda K
authors.initials: AK
authors.lastname: Sarkar
mesh_terms: D017360:Arabidopsis / Q000187:drug effects* / Q000502:physiology*; D029681:Arabidopsis Proteins / Q000037:antagonists & inhibitors; D001549:Benzamides / Q000494:pharmacology*; D003583:Cytokinins / Q000378:metabolism*; D018506:Gene Expression Regulation, Plant; D007210:Indoleacetic Acids / Q000378:metabolism*; D018519:Meristem / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D009284:Naphthols / Q000494:pharmacology*; D063246:Organogenesis, Plant; D050862:Oxidoreductases Acting on Sulfur Group Donors / Q000037:antagonists & inhibitors; D063245:Plant Development; D018517:Plant Roots / Q000187:drug effects* / Q000502:physiology*; D018520:Plant Shoots / Q000187:drug effects / Q000235:genetics / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013234:Stem Cells / Q000187:drug effects* / Q000378:metabolism*
chemical_list: D029681:Arabidopsis Proteins; D001549:Benzamides; D003583:Cytokinins; D007210:Indoleacetic Acids; D009284:Naphthols; C439060:sirtinol; D050862:Oxidoreductases Acting on Sulfur Group Donors; C488954:SIR protein, Arabidopsis