Wang Yuqing, Duan Yingying, Chen Na, Ding Wanyue, Liu Yaowu, Xing Shihai
College of Pharmacy, Anhui University of Chinese Medicine, Hefei, China.
Joint Research Center for Chinese Herbal Medicine of Anhui of Institute of Herbal Medicine (IHM), Bozhou Vocational and Technical College, Bozhou, China.
Front Plant Sci. 2025 Apr 25;16:1531585. doi: 10.3389/fpls.2025.1531585. eCollection 2025.
Indole-3-acetic acid (IAA) is a key plant hormone involved in regulating development and responses to abiotic stress. However, excessive IAA treatment can induce oxidative stress, impair growth, and potentially lead to plant death. This study investigates the effects of excessive IAA exposure on the growth of (Boju), focusing on the underlying molecular mechanisms.
We treated with 10 mg/L IAA for nine consecutive days. The impact of this treatment was assessed from various perspectives, including physiological (chlorophyll, carotenoids, and MDA content), biochemical (antioxidant enzyme activities), and molecular (transcriptomic and metabolomic analyses).
IAA treatment significantly increased chlorophyll a, chlorophyll b, and carotenoid levels by 37%, 46%, and 25%, respectively, compared to pre-treatment levels, suggesting that was experiencing stress. Additionally, the malondialdehyde (MDA) content was 1.79 times higher than pre-treatment levels, confirming oxidative stress. To combat this, the plant enhanced its antioxidant defense mechanisms, as shown by a 93.8% increase in peroxidase (POD) activity and a 45% increase in superoxide dismutase (SOD) activity. Exogenous IAA treatment also led to a significant reduction in endogenous hormone levels, including gibberellins (GA and GA), abscisic acid (ABA), and IAA, with decreases of 93%, 45%, 99%, and 99%, respectively.Transcriptomic and metabolomic analyses identified 263 differentially expressed metabolites and 144 differentially expressed genes.
These results suggest that is experiencing stress under prolonged IAA treatment and likely limits its growth by reducing endogenous hormone levels to mitigate oxidative stress. The transcriptomic and metabolomic results showed the upregulation of stress-related genes, including proB (Glutamate 5-kinase), proA (Glutamate-5-semialdehyde dehydrogenase), GAD (Glutamate decarboxylase), and peroxidases, alongside the downregulation of PK (Pyruvate kinase), indicateing a complex response involving the regulation of amino acid biosynthesis, coumaric acid metabolism, starch and sucrose metabolism, and pyruvate metabolism. This study highlights the nonlinear effects of IAA on plant growth and stress responses, emphasizing the intricate molecular mechanisms involved in coping with excessive IAA-induced stress.
吲哚 - 3 - 乙酸（IAA）是一种关键的植物激素，参与调节植物发育和对非生物胁迫的响应。然而，过量的IAA处理会诱导氧化应激，损害植物生长，并可能导致植物死亡。本研究调查了过量暴露于IAA对（博菊）生长的影响，重点关注其潜在的分子机制。
我们用10 mg/L的IAA连续处理九天。从多个角度评估了这种处理的影响，包括生理方面（叶绿素、类胡萝卜素和丙二醛含量）、生化方面（抗氧化酶活性）以及分子方面（转录组学和代谢组学分析）。
与处理前水平相比，IAA处理使叶绿素a、叶绿素b和类胡萝卜素水平分别显著提高了37%、46%和25%，这表明（博菊）正在经历胁迫。此外，丙二醛（MDA）含量比处理前水平高1.79倍，证实了氧化应激的存在。为应对这种情况，植物增强了其抗氧化防御机制，过氧化物酶（POD）活性增加了93.8%，超氧化物歧化酶（SOD）活性增加了45%。外源IAA处理还导致内源激素水平显著降低，包括赤霉素（GA和GA）、脱落酸（ABA）和IAA，分别降低了93%、45%、99%和99%。转录组学和代谢组学分析确定了263种差异表达的代谢物和144个差异表达的基因。
这些结果表明，（博菊）在长期IAA处理下正经历胁迫，并且可能通过降低内源激素水平来减轻氧化应激，从而限制其生长。转录组学和代谢组学结果显示，与胁迫相关的基因上调，包括脯氨酸B（谷氨酸5 - 激酶）、脯氨酸A（谷氨酸 - 5 - 半醛脱氢酶）、谷氨酸脱羧酶（GAD）和过氧化物酶，同时丙酮酸激酶（PK）下调，这表明存在一个涉及氨基酸生物合成、香豆酸代谢、淀粉和蔗糖代谢以及丙酮酸代谢调节的复杂反应。本研究突出了IAA对植物生长和胁迫响应的非线性影响，强调了应对过量IAA诱导的胁迫所涉及的复杂分子机制。
