Reactive oxygen species regulate auxin levels to mediate adventitious root induction in Arabidopsis hypocotyl cuttings

• Published in: Journal of integrative plant biology Vol. 62; no. 7; pp. 912 - 926
• Main Authors: Huang, Aixia, Wang, Yongshun, Liu, Yangyang, Wang, Guodong, She, Xiaoping
• Format: Journal Article
• Language: English
• Published: China (Republic : 1949- ) Wiley Subscription Services, Inc 01.07.2020; College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
• Subjects: adventitious roots; Arabidopsis; Arabidopsis - genetics; Arabidopsis - metabolism; Arabidopsis Proteins - metabolism; Arabidopsis thaliana; auxins; Biological Transport - genetics; Biosynthesis; Biosynthetic Pathways - genetics; Breeding; Cell Wall - enzymology; chlorides; Cutting; Cuttings; excision; Fluorescence; forests; Gene Expression Regulation, Plant; genes; Homology; horticulture; Hypocotyl - metabolism; hypocotyls; Indoleacetic Acids - metabolism; mutants; Mutation - genetics; NAD(P)H oxidase; NAD(P)H oxidase (H2O2-forming); NADPH Oxidases - metabolism; Oxidase; Peroxidase - metabolism; Plant hormones; Plant Roots - growth & development; Plant Roots - metabolism; Propagation; Protein D; Proteins; Reactive oxygen species; Reactive Oxygen Species - metabolism; Respiratory Burst; Respiratory burst oxidase; rooting; Time Factors; Transcription; Wounds
• ISSN: 1672-9072; 1744-7909; 1744-7909
• DOI: 10.1111/jipb.12870

Adventitious root (AR) formation from leafy stem cuttings is critical for breeding of many forest and horticultural species. In addition to the plant hormone auxin, wound‐induced signaling caused by the cutting excision is also essential for AR initiation. Here we found that reactive oxygen species (ROS) are rapidly generated at the excision site as a wound‐induced signal and propagated throughout the hypocotyl cutting after excision of the Arabidopsis (Arabidopsis thaliana) primary root. ROS propagation was not observed in the presence of an NADPH oxidase inhibitor (diphenylene iodonium chloride) or in a knockout mutant of the NADPH oxidase gene respiratory burst oxidase homolog protein D (RBOHD). Respiratory burst oxidase homolog protein D was specifically upregulated in hypocotyl cuttings at 0.5 h post excision (hpe). Together, these data suggest that RBOHD mediates ROS propagation in hypocotyl cuttings. We also found that auxin levels increased significantly in the shoot apex at 5 hpe and at the base of the cutting at 6 hpe; these effects were blocked by treatment with ROS scavengers. Consistent with this, transcript levels of auxin biosynthesis and polar‐transport genes generally increased between 1 to 6 hpe. Collectively, our results suggest that wound‐induced ROS participate in AR induction through regulation of auxin biosynthesis and transport. In this study, we focused on the production, propagation, and action of wound‐induced ROS in Arabidopsis hypocotyl cuttings. An ROS burst occurs in response to primary root excision and that the resulting ROS propagate through the hypocotyl. As a result of increased biosynthesis and transport, auxin initiates adventitious root formation.