Wan Jinpeng, Wang Ruling, Zhang Ping, Sun Liangliang, Ju Qiong, Huang Haodong, Lü Shiyou, Tran Lam-Son, Xu Jin
CAS Key Laboratory of Tropical Plant Resources and Sustainable Use, Xishuangbanna Tropical Botanical Garden, Chinese Academy of Sciences, Menglun, Mengla, Yunnan 666303, China.
Center of Economic Botany, Core Botanical Gardens, Chinese Academy of Sciences, Menglun, Mengla 666303, China.
iScience. 2021 Oct 7;24(11):103228. doi: 10.1016/j.isci.2021.103228. eCollection 2021 Nov 19.
Crosstalk among ABA, auxin, and ROS plays critical roles in modulating seed germination, root growth, and suberization. However, the underlying molecular mechanisms remain largely elusive. Here, MYB70, a R2R3-MYB transcription factor was shown to be a key component of these processes in . seeds displayed decreased sensitivity, while MYB70-overexpressing seeds showed increased sensitivity in germination in response to exogenous ABA through MYB70 physical interaction with ABI5 protein, leading to enhanced stabilization of ABI5. Furthermore, MYB70 modulates root system development (RSA) which is associated with increased conjugated IAA content and HO/O ratio but reduced root suberin deposition, consequently affecting nutrient uptake. In support of these data, MYB70 positively regulates the expression of auxin conjugation-related , while negatively peroxidase-encoding and suberin biosynthesis-related genes. Our findings collectively revealed a previously uncharacterized component that modulates ABA and auxin signaling pathways, HO/O balance, and suberization, consequently regulating RSA and seed germination.
脱落酸（ABA）、生长素和活性氧（ROS）之间的相互作用在调节种子萌发、根系生长和木栓化过程中起着关键作用。然而，其潜在的分子机制仍 largely 难以捉摸。在这里，R2R3-MYB 转录因子 MYB70 被证明是这些过程在 中的关键组成部分。种子表现出敏感性降低，而 MYB70 过表达的种子通过 MYB70 与 ABI5 蛋白的物理相互作用，对外源 ABA 的萌发敏感性增加，导致 ABI5 的稳定性增强。此外，MYB70 调节根系发育（RSA），这与结合态 IAA 含量和 HO/O 比率增加但根木栓质沉积减少有关，从而影响养分吸收。为支持这些数据，MYB70 正向调节生长素结合相关 的表达，而负向调节过氧化物酶编码和木栓质生物合成相关基因。我们的研究结果共同揭示了一个以前未被表征的成分，它调节 ABA 和生长素信号通路、HO/O 平衡和木栓化，从而调节 RSA 和种子萌发。
