Molecular Plant Physiology, Institute of Environmental Biology, Utrecht University, Padualaan 8, Utrecht, 3584 CH, the Netherlands.
Department of Molecular Genetics and Physiology of Plants, Faculty of Biology and Biotechnology, Universitätsstraße 150, Bochum, 44801, Germany.
Plant J. 2021 Jun;106(6):1523-1540. doi: 10.1111/tpj.15250. Epub 2021 May 6.
Temperature passively affects biological processes involved in plant growth. Therefore, it is challenging to study the dedicated temperature signalling pathways that orchestrate thermomorphogenesis, a suite of elongation growth-based adaptations that enhance leaf-cooling capacity. We screened a chemical library for compounds that restored hypocotyl elongation in the pif4-2-deficient mutant background at warm temperature conditions in Arabidopsis thaliana to identify modulators of thermomorphogenesis. The small aromatic compound 'Heatin', containing 1-iminomethyl-2-naphthol as a pharmacophore, was selected as an enhancer of elongation growth. We show that ARABIDOPSIS ALDEHYDE OXIDASES redundantly contribute to Heatin-mediated hypocotyl elongation. Following a chemical proteomics approach, the members of the NITRILASE1-subfamily of auxin biosynthesis enzymes were identified among the molecular targets of Heatin. Our data reveal that nitrilases are involved in promotion of hypocotyl elongation in response to high temperature and Heatin-mediated hypocotyl elongation requires the NITRILASE1-subfamily members, NIT1 and NIT2. Heatin inhibits NIT1-subfamily enzymatic activity in vitro and the application of Heatin accordingly results in the accumulation of NIT1-subfamily substrate indole-3-acetonitrile in vivo. However, levels of the NIT1-subfamily product, bioactive auxin (indole-3-acetic acid), were also significantly increased. It is likely that the stimulation of hypocotyl elongation by Heatin might be independent of its observed interaction with NITRILASE1-subfamily members. However, nitrilases may contribute to the Heatin response by stimulating indole-3-acetic acid biosynthesis in an indirect way. Heatin and its functional analogues present novel chemical entities for studying auxin biology.
温度被动影响参与植物生长的生物过程。因此，研究专门的温度信号通路以协调热形态发生是具有挑战性的，热形态发生是一系列基于伸长生长的适应，可增强叶片冷却能力。我们在拟南芥中筛选了一个化学文库，以寻找在温暖条件下恢复 pif4-2 缺陷突变体背景下下胚轴伸长的化合物，以鉴定热形态发生的调节剂。小分子芳香化合物“Heatin”，含有作为药效团的 1-亚氨基-2-萘酚，被选为伸长生长的增强剂。我们表明，拟南芥醛氧化酶冗余地促进 Heatin 介导的下胚轴伸长。通过化学蛋白质组学方法，鉴定出生长素生物合成酶的 nitrilase1 亚家族成员是 Heatin 的分子靶标之一。我们的数据表明，nitrilases 参与了对高温的下胚轴伸长的促进，并且 Heatin 介导的下胚轴伸长需要 nitrilase1 亚家族成员 NIT1 和 NIT2。Heatin 在体外抑制 nitrilase1 亚家族的酶活性，并且 Heatin 的应用导致体内 nitrilase1 亚家族底物吲哚-3-乙腈的积累。然而，nitrilase1 亚家族产物，生物活性生长素（吲哚-3-乙酸）的水平也显著增加。Heatin 刺激下胚轴伸长可能与其与 nitrilase1 亚家族成员的观察到的相互作用无关。然而，nitrilases 可能通过以间接方式刺激吲哚-3-乙酸生物合成来促进 Heatin 反应。Heatin 及其功能类似物为研究生长素生物学提供了新的化学实体。
