A crosstalk between auxin and brassinosteroid regulates leaf shape by modulating growth anisotropy
A crosstalk between auxin and brassinosteroid regulates leaf shape by modulating growth anisotropy
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生长素和油菜素类固醇之间的串扰通过调节生长各向异性来调节叶子形状
DOI：
10.1016/j.molp.2021.03.011
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发表时间：
2021
期刊：
影响因子：
27.5
通讯作者：
Jiao Yuling
中科院分区：
文献类型：
--
作者：
Xiong Yuanyuan;Wu Binbin;Du Fei;Guo Xiaolu;Tian Caihuan;Hu Jinrong;Lü Shouqin;Long Mian;Zhang Lei;Wang Ying;Jiao Yuling
树叶的形状在植物内部和物种之间变化很大，从细长到椭圆形不等。这在很大程度上是由生长的近端轴线决定的。然而，关于近端-远端生长是如何控制来决定叶片形状的，人们知之甚少。在这里，我们表明，拟南芥叶片和萼片近端生长是由两种植物激素调节的。两个A类生长素反应因子(ARF6和ARF8)激活DWARF4的转录，DWARF4编码一个关键的油菜素类固醇(BR)生物合成酶。在细胞水平上，植物激素促进沿近端远端轴的更定向的细胞扩张，以及最终的细胞大小。BRs促进细胞壁果胶的脱甲基酯化，导致各向同性的平面内细胞壁疏松。值得注意的是，数值模拟表明，各向同性的细胞壁松动可以导致细胞和器官沿近端轴定向生长。综上所述，我们表明生长素通过BRs的生物合成来决定细胞壁的力学和细胞的定向生长，从而产生可变圆度的叶片。
Leaf shape is highly variable within and among plant species, ranging from slender to oval shaped. This is largely determined by the proximodistal axis of growth. However, little is known about how proximal–distal growth is controlled to determine leaf shape. Here, we show thatArabidopsisleaf and sepal proximodistal growth is tuned by two phytohormones. Two class A AUXIN RESPONSE FACTORs (ARFs), ARF6 and ARF8, activate the transcription ofDWARF4, which encodes a key brassinosteroid (BR) biosynthetic enzyme. At the cellular level, the phytohormones promote more directional cell expansion along the proximodistal axis, as well as final cell sizes. BRs promote the demethyl-esterification of cell wall pectins, leading to isotropic in-plane cell wall loosening. Notably, numerical simulation showed that isotropic cell wall loosening could lead to directional cell and organ growth along the proximodistal axis. Taken together, we show that auxin acts through biosynthesis of BRs to determine cell wall mechanics and directional cell growth to generate leaves of variable roundness.