Auxin promotes fiber elongation by enhancing gibberellic acid biosynthesis in cotton

作者：Liping Zhu, Bin Jiang, Jiaojie Zhu, Guanghui Xiao · 发表于：Plant Biotechnology Journal · 年份：2021 · DOI：10.1111/pbi.13771 · 被引用次数：65 · 研究领域：Research in Cotton Cultivation、Plant Molecular Biology Research、Plant Virus Research Studies

Cotton is an important cash crop grown worldwide, (Huang et al., 2021; Ma et al., 2018; Wang et al., 2019), which fibers are regulated by multiple phytohormones (Liu et al., 2020; Shan et al., 2014; Zhang et al., 2011). Targeted expression IAA biosynthesis gene enhances both fiber yield and quality (Zhang et al., 2011). Exogenous application of GA also improved fiber length (Shan et al., 2014). However, mechanism by which auxin and GA promote cotton fiber development and whether there is cross-talk between them remains unclear. Our study shows that auxin promotes fiber development by enhancing GA biosynthesis. To investigate the regulatory relationships between auxin- and GA- regulated fiber development, we observed fiber phenotype after exogenous application of IAA and GA1 and corresponding inhibitors. The results showed that IAA and GA1 promoted fiber elongation, N-1-naphthylphthalamic acid (NPA, a polar auxin transport inhibitor), and paclobutrazol (PAC, a GA biosynthesis inhibitor) inhibited fiber development. GA1 rescues fiber elongation inhibited by NPA, whereas IAA did not rescue shortened fibers by PAC treatment (Figure 1a), suggesting that GA may function downstream of IAA in regulating fiber development. Consistently, GA1 content was increased and decreased after IAA and NPA treatment, respectively (Figure 1b). Our previous work showed that auxin responsive factor 18 (GhARF18) was a key regulator in fiber development (Xiao et al., 2018) and GhARF18 transcripts were ...