Wang Xiuyu, Liu Cuixia, Li Tian, Zhou Fangyu, Sun Haotian, Li Fali, Ma Ying, Jia Honglei, Zhang Xiaoyue, Shi Wei, Gong Chunmei, Li Jisheng
College of Life Sciences, Northwest A&F University, Yangling, Shaanxi, 712100, China.
College of Horticulture, Northwest A&F University, Yangling, Shaanxi, 712100, China.
New Phytol. 2024 Nov;244(4):1377-1390. doi: 10.1111/nph.20122. Epub 2024 Sep 15.
Hydrogen sulfide (HS) is an endogenous gaseous signaling molecule, which has been shown to play an important role in plant growth and development by coupling with various phytohormones. However, the relationship between HS and cytokinin (CTK) and the mechanisms by which HS and CTK affect root growth remain poorly understood. Endogenous CTK was analyzed by UHPLC-ESI-MS/MS. Persulfidation of cytokinin oxidase/dehydrogenases (CKXs) was analyzed by mass spectrometry (MS). ckx2/CKX2, OE CKX2 and ckx2/CKX2 transgenic lines were isolated with the ckx2 background. HS is linked to CTK content by CKX2, which regulates root system architecture (RSA). Persulfidation at cysteine (Cys)62 residue of CKX2 enhances CKX2 activity, resulting in reduced CTK content. We utilized 35S-LCD/oasa1 transgenic lines to investigate the effect of endogenous HS on RSA, indicating that HS reduces the gravitropic set-point angle (GSA), shortens root hairs, and increases the number of lateral roots (LRs). The persulfidation of CKX2 changes the elongation of cells on the upper and lower flanks of LR elongation zone, confirming that Cys62 of CKX2 is the specificity target of HS to regulate RSA in vivo. In conclusion, this study demonstrated that HS negatively regulates CTK content and affects RSA by persulfidation of CKX2 in Arabidopsis thaliana.
硫化氢（HS）是一种内源性气体信号分子，已证明其通过与多种植物激素相互作用在植物生长发育中发挥重要作用。然而，HS与细胞分裂素（CTK）之间的关系以及HS和CTK影响根系生长的机制仍知之甚少。通过超高效液相色谱-电喷雾串联质谱（UHPLC-ESI-MS/MS）分析内源性CTK。通过质谱（MS）分析细胞分裂素氧化酶/脱氢酶（CKXs）的过硫化作用。以ckx2为背景分离出ckx2/CKX2、OE CKX2和ckx2/CKX2转基因系。HS通过CKX2与CTK含量相关联，CKX2调节根系结构（RSA）。CKX2半胱氨酸（Cys）62残基处的过硫化作用增强了CKX2活性，导致CTK含量降低。我们利用35S-LCD/oasa1转基因系研究内源性HS对RSA的影响，结果表明HS降低了重力设定点角度（GSA），缩短了根毛，并增加了侧根（LRs）的数量。CKX2的过硫化作用改变了LR伸长区上下两侧细胞的伸长，证实CKX2的Cys62是HS在体内调节RSA的特异性靶点。总之，本研究表明HS通过对拟南芥中CKX2的过硫化作用负向调节CTK含量并影响RSA。
