Auxin (Indole-3-acetic acid, IAA) is essential for anther development and male fertility, but little is known about its homeostasis in developing anthers due to its complex and diverse synthesis pathways. Here, we employed transcriptomic, targeted metabolomic, and amino acid analyses on a wild type (WT) cotton (Gossypium hirsutum) line SD98–6 and its nearly-isogenic male sterile (MS) line SD98–6A, to delve into the relationship between IAA and anther fertility. In WT anthers, IAA homeostasis was achieved mainly through self-synthesis, conjugate hydrolysis, and polar transport, and accumulation of IAA exhibited an inverted "U" pattern with the highest content observed at the tetrad stage. In MS anthers, no IAA accumulation was observed after the meiosis stage and the IAA content remained constantly low, mainly due to reduction of the substrates (phenylalanine and tryptophan) for IAA synthesis, and significantly decreased expression of the genes involved in IAA synthesis. Meanwhile, carbohydrate metabolism pathways directly contributing to IAA synthesis and synthesis of amino acids were malfunctional in MS anthers based on the expression profile of the metabolic genes and content measurement. These results provide valuable insights into the IAA homeostasis in cotton anthers and imply that genes related to IAA homeostasis are potential targets for development of IAA-sensitive male sterile cotton lines.

生长素（3-吲哚乙酸，IAA）对于花药发育和雄性生育力至关重要，但由于其复杂多样的合成途径，人们对其在花药发育过程中的稳态知之甚少。在这里，我们对野生型 (WT) 棉花 ( Gossypium hirsutum ) 品系 SD98–6 及其近等基因雄性不育 (MS) 品系 SD98–6A 进行转录组学、靶向代谢组学和氨基酸分析，以深入研究两者之间的关系。 IAA 和花药育性。在WT花药中，IAA稳态主要通过自身合成、结合物水解和极性运输来实现，并且IAA的积累呈现倒“U”型模式，在四分体阶段观察到含量最高。在MS花药中，减数分裂期后没有观察到IAA积累，IAA含量一直保持在较低水平，这主要是由于IAA合成底物（苯丙氨酸和色氨酸）减少，以及参与IAA合成的基因表达显着降低。同时，根据代谢基因的表达谱和含量测量，直接促进 IAA 合成和氨基酸合成的碳水化合物代谢途径在 MS 花药中出现故障。这些结果为棉花花药中 IAA 稳态提供了有价值的见解，并暗示与 IAA 稳态相关的基因是开发 IAA 敏感雄性不育棉花品系的潜在靶标。