School of Life Science, Jiangsu Normal University, Xuzhou, Jiangsu 221116, People's Republic of China.
Public Technical Service Center, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650223, People's Republic of China.
Proc Natl Acad Sci U S A. 2023 Jun 13;120(24):e2302854120. doi: 10.1073/pnas.2302854120. Epub 2023 Jun 5.
Stomata are pores found in the epidermis of stems or leaves that modulate both plant gas exchange and water/nutrient uptake. The development and function of plant stomata are regulated by a diverse range of environmental cues. However, how carbohydrate status in preexisting leaves might determine systemic stomatal formation within newly developing leaves has remained obscure. The glucose (Glc) sensor HEXOKINASE1 (HXK1) has been reported to decrease the stability of an ethylene/Glc signaling transcriptional regulator, EIN3 (ETHYLENE INSENSITIVE3). EIN3 in turn directly represses the expression of (), encoding a master transporter of sucrose (Suc). Further, KIN10, a nuclear regulator involved in energy homeostasis, has been reported to repress the transcription factor SPCH (SPEECHLESS), a master regulator of stomatal development. Here, we demonstrate that the Glc status of preexisting leaves determines systemic stomatal development within newly developing leaves by the HXK1-¦EIN3-¦SUC2 module. Further, increasing Glc levels in preexisting leaves results in a HXK1-dependent decrease of EIN3 and increase of SUC2, triggering the perception, amplification and relay of HXK1-dependent Glc signaling and thereby triggering Suc transport from mature to newly developing leaves. The HXK1-¦EIN3-¦SUC2 molecular module thereby drives systemic Suc transport from preexisting leaves to newly developing leaves. Subsequently, increasing Suc levels within newly developing leaves promotes stomatal formation through the established KIN10⟶ SPCH module. Our findings thus show how a carbohydrate signal in preexisting leaves is sensed, amplified and relayed to determine the extent of systemic stomatal development within newly developing leaves.
气孔是茎或叶表皮上的孔，调节植物气体交换和水/养分吸收。植物气孔的发育和功能受多种环境线索的调节。然而，现存叶片中的碳水化合物状态如何决定新发育叶片中系统气孔的形成仍然不清楚。葡萄糖（Glc）传感器己糖激酶 1（HXK1）已被报道降低乙烯/Glc 信号转导转录调节剂 EIN3（ETHYLENE INSENSITIVE3）的稳定性。EIN3 反过来直接抑制蔗糖（Suc）主要转运体编码基因（）的表达。此外，参与能量稳态的核调节因子 KIN10 已被报道抑制转录因子 SPCH（SPEECHLESS），这是气孔发育的主要调节因子。在这里，我们通过 HXK1-¦EIN3-¦SUC2 模块证明了现存叶片的 Glc 状态通过 HXK1-¦EIN3-¦SUC2 模块决定新发育叶片中的系统气孔发育。此外，增加现存叶片中的 Glc 水平会导致 HXK1 依赖性 EIN3 减少和 SUC2 增加，从而触发 HXK1 依赖性 Glc 信号的感知、放大和传递，并触发 Suc 从成熟叶片向新发育叶片的运输。因此，HXK1-¦EIN3-¦SUC2 分子模块驱动系统 Suc 从现存叶片向新发育叶片的运输。随后，新发育叶片中 Suc 水平的增加通过已建立的 KIN10⟶ SPCH 模块促进气孔形成。因此，我们的研究结果表明，现存叶片中的碳水化合物信号是如何被感知、放大和传递的，以决定新发育叶片中系统气孔发育的程度。
