Nomura Takahito, Seto Yoshiya, Kyozuka Junko
Center for Bioscience Research and Education, Utsunomiya University, Utsunomiya, Japan.
School of Agriculture, Meiji University, Kawasaki, Japan.
J Exp Bot. 2024 Feb 12;75(4):1134-1147. doi: 10.1093/jxb/erad412.
Strigolactone is the collective name for compounds containing a butenolide as a part of their structure, first discovered as compounds that induce seed germination of root parasitic plants. They were later found to be rhizosphere signaling molecules that induce hyphal branching of arbuscular mycorrhizal fungi, and, finally, they emerged as a class of plant hormones. Strigolactones are found in root exudates, where they display a great variability in their chemical structure. Their structure varies among plant species, and multiple strigolactones can exist in one species. Over 30 strigolactones have been identified, yet the chemical structure of the strigolactone that functions as an endogenous hormone and is found in the above-ground parts of plants remains unknown. We discuss our current knowledge of the synthetic pathways of diverse strigolactones and their regulation, as well as recent progress in identifying strigolactones as plant hormones. Strigolactone is perceived by the DWARF14 (D14), receptor, an α/β hydrolase which originated by gene duplication of KARRIKIN INSENSITIVE 2 (KAI2). D14 and KAI2 signaling pathways are partially overlapping paralogous pathways. Progress in understanding the signaling mechanisms mediated by two α/β hydrolase receptors as well as remaining challenges in the field of strigolactone research are reviewed.
独脚金内酯是一类结构中含有丁烯内酯的化合物的统称，最初被发现是诱导根寄生植物种子萌发的化合物。后来发现它们是根际信号分子，可诱导丛枝菌根真菌的菌丝分支，最终，它们成为一类植物激素。独脚金内酯存在于根系分泌物中，其化学结构具有很大的变异性。它们的结构因植物种类而异，一个物种中可能存在多种独脚金内酯。已鉴定出30多种独脚金内酯，但在植物地上部分作为内源激素存在的独脚金内酯的化学结构仍不清楚。我们讨论了目前对多种独脚金内酯合成途径及其调控的认识，以及将独脚金内酯鉴定为植物激素方面的最新进展。独脚金内酯由DWARF14（D14）受体感知，D14是一种α/β水解酶，由KARRIKIN INSENSITIVE 2（KAI2）基因复制产生。D14和KAI2信号通路是部分重叠的旁系同源通路。综述了在理解由两种α/β水解酶受体介导的信号传导机制方面的进展以及独脚金内酯研究领域中仍然存在的挑战。
