ENHANCED GRAVITROPISM 2 encodes a STERILE ALPHA MOTIVE containing protein that controls root growth angle in barley and wheat
ENHANCED GRAVITROPISM 2 encodes a STERILE ALPHA MOTIVE containing protein that controls root growth angle in barley and wheat
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ENHANCED GRAVITROPISM 2 编码含有控制大麦和小麦根部生长角度的蛋白质的 STERILE ALPHA MOTIVE
DOI：
10.1101/2021.01.23.427880
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发表时间：
2021
期刊：
影响因子：
--
通讯作者：
Kirschner G
中科院分区：
文献类型：
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作者：
Kirschner G
根系生长角定义了根系如何向重力矢量生长，是根系构型最重要的决定因素之一。它控制着作物的吸水能力、养分利用效率、抗逆能力，并因此控制着作物的产量。我们证明了egt 2（增强向地性2）突变体大麦表现出更陡峭的种子根和侧根的根生长和生长素的非依赖性更高的响应重力相比，野生型植物。我们通过混合分离分析和全基因组测序相结合的方法克隆了EGT 2基因。随后通过一个独立的CRISPR/Cas9突变等位基因进行的验证实验证明，tegt 2编码一个含有无菌α基序结构域的蛋白。原位杂交实验表明EGT 2在根冠至伸长区均有表达。我们通过敲除四倍体硬粒小麦A和B基因组中的EGT 2直向同源基因，证明了EGT 2在大麦和小麦之间根生长角度控制中的进化保守作用。通过结合激光捕获显微切割和RNA测序，我们观察到7个expansin基因在延伸区转录下调。这与EGT 2在根的这一区域中的作用一致，在该区域中，重力感应的效果通过差分细胞伸长来执行。我们的研究结果表明EGT 2是大麦和小麦根生长角的进化保守调节因子，可能是基于根的谷物作物改良策略的有价值的目标。
The root growth angle defines how roots grow toward the gravity vector and is among the most important determinants of root system architecture. It controls water uptake capacity, nutrient use efficiency, stress resilience, and, as a consequence, yield of crop plants. We demonstrated that theegt2(enhanced gravitropism 2) mutant of barley exhibits steeper root growth of seminal and lateral roots and an auxin-independent higher responsiveness to gravity compared to wild-type plants. We cloned theEGT2gene by a combination of bulked-segregant analysis and whole genome sequencing. Subsequent validation experiments by an independent CRISPR/Cas9 mutant allele demonstrated thategt2encodes a STERILE ALPHA MOTIF domain–containing protein. In situ hybridization experiments illustrated thatEGT2is expressed from the root cap to the elongation zone. We demonstrated the evolutionary conserved role ofEGT2in root growth angle control between barley and wheat by knocking out theEGT2orthologs in the A and B genomes of tetraploid durum wheat. By combining laser capture microdissection with RNA sequencing, we observed that seven expansin genes were transcriptionally down-regulated in the elongation zone. This is consistent with a role ofEGT2in this region of the root where the effect of gravity sensing is executed by differential cell elongation. Our findings suggest thatEGT2is an evolutionary conserved regulator of root growth angle in barley and wheat that could be a valuable target for root-based crop improvement strategies in cereals.