HOMEOBOX PROTEIN 24 mediates the conversion of indole-3-butyric acid to indole-3-acetic acid to promote root hair elongation
HOMEOBOX PROTEIN 24 mediates the conversion of indole-3-butyric acid to indole-3-acetic acid to promote root hair elongation
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HOMEOBOX PROTEIN 24 介导吲哚-3-丁酸转化为吲哚-3-乙酸，促进根毛伸长
DOI：
10.1111/nph.17719
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发表时间：
2021
期刊：
影响因子：
9.4
通讯作者：
Lei Zhu
中科院分区：
文献类型：
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作者：
Huan Zhao;Yutao Wang;Shuai Zhao;Ying Fu;Lei Zhu
吲哚-3-乙酸（Indole-3-acetic acid，IAA）是植物中活性生长素的主要形式。IAA除了通过新生生物合成和结合物形式的释放外，还可以从其前体吲哚-3-丁酸（IBA）转化而来。IBA衍生的IAA可能有助于驱动拟南芥幼苗根毛的伸长，但IBA向IAA的转化如何受到调控并影响IAA的功能还需要进一步研究。鉴定了锌指-同源结构域蛋白质家族（ZF-HD家族）中的转录因子。随着HB 24功能的丧失，根毛的生长出现缺陷。吲哚-3-丁酸反应1（IBR 1），编码一种参与IBA-到-IAA转化的酶，被鉴定为HB 24控制根毛伸长的直接靶标。外源IAA或生长素类似物1-萘乙酸（NAA）均能挽救hb 24突变体的根毛生长表型，但IBA不能，提示HB 24可能参与了IBA-IAA转化过程，因此HB 24可能通过上调IBR 1的表达进而促进IBA-IAA转化参与根毛伸长。此外，IAA还提高了HB 24的表达，表明反馈回路参与了IBA到IAA转化介导的根毛伸长。
Indole‐3‐acetic acid (IAA) is a predominant form of active auxin in plants. In addition tode novobiosynthesis and release from its conjugate forms, IAA can be converted from its precursor indole‐3‐butyric acid (IBA).The IBA‐derived IAA may help drive root hair elongation inArabidopsis thalianaseedlings, but how the IBA‐to‐IAA conversion is regulated and affects IAA function requires further investigation.In this study, HOMEOBOX PROTEIN 24 (HB24), a transcription factor in the zinc finger‐homeodomain family (ZF‐HD family) of proteins, was identified. With loss ofHB24function, defective growth occurred in root hairs.INDOLE‐3‐BUTYRIC ACID RESPONSE 1(IBR1), which encodes an enzyme involved in the IBA‐to‐IAA conversion, was identified as a direct target of HB24 for the control of root hair elongation. The exogenous IAA or auxin analogue 1‐naphthalene acetic acid (NAA) both rescued the root hair growth phenotype ofhb24mutants, but IBA did not, suggesting a role forHB24in the IBA‐to‐IAA conversion.Therefore,HB24participates in root hair elongation by upregulating the expression ofIBR1and subsequently promoting the IBA‐to‐IAA conversion. Moreover, IAA also elevated the expression ofHB24, suggesting a feedback loop is involved in IBA‐to‐IAA conversion‐mediated root hair elongation.