Auxin and Cell Wall Crosstalk as Revealed by the Arabidopsis thaliana Cellulose Synthase Mutant Radially Swollen 1
Auxin and Cell Wall Crosstalk as Revealed by the Arabidopsis thaliana Cellulose Synthase Mutant Radially Swollen 1
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DOI：
10.1093/pcp/pcz055
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发表时间：
2019-07-01
影响因子：
4.9
通讯作者：
Sanguinet, Karen A.
中科院分区：
文献类型：
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作者：
Lehman, Thiel A.;Sanguinet, Karen A.
植物细胞自身被包裹在由多糖、蛋白质和酶组成的复杂晶格中，形成一个被称为细胞壁的完整基质。纤维素微纤维是细胞壁的主要组成部分，在整个细胞生长过程中由纤维素合成酶A(CESA)蛋白在质膜上合成，并负责膨胀驱动的各向异性膨胀。激素信号和细胞壁生物合成之间的关系早就被提出，但最近发现了直接的联系，揭示了激素在纤维素生物合成中发挥关键调节作用。拟南芥CESA1的径向膨胀1(Rsw1)等位基因含有单一的氨基酸变化，使蛋白质在高温下不稳定。我们利用rsw1的条件性来研究生长素对各向同性生长的贡献。我们发现，在30℃的限制温度下，外源生长素处理降低了rsw1根的各向同性膨胀。我们还通过AUX1-YFP的共聚焦成像发现，即使在19℃的允许温度下，rsw1与野生型根之间的生长素内流也减少了。此外，rsw1显示生长素反应基因和CESA基因的错误表达。此外，我们使用DiI-Venus和DR5：vYFP生长素报告发现，在肿胀开始时，rsw1突变根中的生长素最大值发生了变化。总体而言，我们得出结论，细胞壁生物合成中断扰乱了生长素的运输，导致生长素动态平衡改变，影响了各向异性和各向同性的生长，从而影响了整个根的形态。
Plant cells sheath themselves in a complex lattice of polysaccharides, proteins and enzymes forming an integral matrix known as the cell wall. Cellulose microfibrils, the primary component of cell walls, are synthesized at the plasma membrane by CELLULOSE SYNTHASE A (CESA) proteins throughout cellular growth and are responsible for turgor-driven anisotropic expansion. Associations between hormone signaling and cell wall biosynthesis have long been suggested, but recently direct links have been found revealing hormones play key regulatory roles in cellulose biosynthesis. The radially swollen 1 (rsw1) allele of Arabidopsis thaliana CESA1 harbors a single amino acid change that renders the protein unstable at high temperatures. We used the conditional nature of rsw1 to investigate how auxin contributes to isotropic growth. We found that exogenous auxin treatment reduces isotropic swelling in rsw1 roots at the restrictive temperature of 30 degrees C. We also discovered decreases in auxin influx between rsw1 and wildtype roots via confocal imaging of AUX1-YFP, even at the permissive temperature of 19 degrees C. Moreover, rsw1 displayed mis-expression of auxin-responsive and CESA genes. Additionally, we found altered auxin maxima in rsw1 mutant roots at the onset of swelling using DII-VENUS and DR5:vYFP auxin reporters. Overall, we conclude disrupted cell wall biosynthesis perturbs auxin transport leading to altered auxin homeostasis impacting both anisotropic and isotropic growth that affects overall root morphology.