Characterization of the cellular and molecular defects induced by the boron deficiency mimic phenylboronic acid in the primary root of maize

微量营养元素硼的缺乏是一种普遍的非生物胁迫，导致包括玉米在内的许多作物的产量急剧下降。潜在的分子原因只是部分了解。硼以硼酸的形式被植物吸收，理解硼功能的关键在于它与顺式二醇基团结合的能力。尽管在植物细胞内存在许多硼的潜在结合伴侣，但仅显示硼结合细胞壁中的两个鼠李半乳糖醛酸-II分子，更重要的是交联两个鼠李半乳糖醛酸-II分子。是否有额外的结合伙伴的硼和硼细胞壁外是否是生物学上的重要性是在该领域的开放性问题。为了解决这些问题，拟议的项目将利用化学品苯基硼酸（PBA），这是一种硼酸类似物。像硼酸一样，PBA仍然将硼输送到细胞中，并且可以与顺式二醇基团结合。与硼酸不同，PBA不能交联分子，因此用于诱导缺硼样缺陷。PBA具有鉴定硼的其他功能的潜力，尽管其具有交联功能和硼的其他结合配偶体。拟议的项目将描述PBA在玉米主根中引起的细胞和分子缺陷，并将其与缺硼引起的缺陷进行比较。重点将放在细胞分裂，细胞扩张，分生组织发育，乙烯生物合成，生长素运输和细胞分裂素信号。此外，拟议的项目将通过正向化学筛选和蛋白质组学方法确定PBA的靶点。

Deficiency of the micronutrient boron is a widespread abiotic stress leading to drastic yield reductions in many crops, including maize. The underlying molecular causes are only partially understood. Boron is accessible to plants in form of boric acid and the key in understanding boron function lies in its ability to bind to cis-diol groups. Although there are many potential binding partners of boron within a plant cell, it has only been shown to bind to and more importantly to crosslink two Rhamnogalacturonan-II molecules in the cell wall. Whether there are additional binding partners of boron and whether boron outside the cell wall is of biological importance are open questions in the field. To address these questions, the proposed project will make use of the chemical phenylboronic acid (PBA), which is a boric acid analog. Like boric acid, PBA still delivers boron into the cell and can bind to cis-diol groups. Unlike boric acid, PBA cannot cross link molecules and is therefore used to induce boron-deficiency like defects. PBA has the potential to identify additional functions of boron despite its crosslinking function and additional binding partners of boron. The proposed project will characterize the cellular and molecular defects induced by PBA in the maize primary root and will compare them to defects induced by boron deficiency. Special emphasis will be put on cell division, cell expansion, meristem development, ethylene biosynthesis, auxin transport and cytokinin signaling. Additionally, the proposed project will identify targets of PBA through forward chemical screening and proteomics approaches.