The axr2-1 mutation of Arabidopsis thaliana is a gain-of-function mutation that disrupts an early step in auxin response.
The axr2-1 mutation of Arabidopsis thaliana is a gain-of-function mutation that disrupts an early step in auxin response.
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DOI：
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发表时间：
1994-12
期刊：
影响因子：
3.3
通讯作者：
C. Timpte;Allison K. Wilson;M. Estelle
中科院分区：
文献类型：
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作者：
C. Timpte;Allison K. Wilson;M. Estelle
拟南芥的显性突变axr2-1对植物激素生长素、乙烯和脱落酸具有抗性。此外，axr2-1对植物形态具有多向性影响，包括axr2-1植株的根、下胚轴和花序的向地性缺陷。在AXR2位点进行了两次基因筛选以分离新的突变。首先，对axr2-1花粉进行γ辐照，将其杂交到野生型植株上，并对M1后代进行axr2-1表型丧失筛选。3号染色体axr2-1区域大量缺失；然而，这些缺失似乎都不是可遗传的。其次，从axr2-1 gl-1植株中获得M2种子，筛选axr2-1表型的逆转。其中一个可逆系，axr2-r3，具有由axr2位点的第二个突变引起的独特表型。为了进一步了解AXR2 -1突变的性质，通过比较以下基因型：+/+、+/+/+、AXR2 -1/ AXR2 -1、AXR2 -1/+、AXR2 -1/+和AXR2 -1/+/+，研究了改变AXR2基因野生型与突变型的比例对植物的影响。此外，研究人员还检测了生长素诱导的SAUR-AC1基因转录本的积累情况，以确定野生型和突变型植物对生长素的反应。野生型幼苗和成熟植株在生长素处理下积累转录本。相反，axr2-1组织在生长素的作用下不会积累SAUR-AC1转录本。综上所述，这些结果表明，axr2-1是一个新形态或超形态突变，破坏了生长素反应途径的早期步骤。
The dominant axr2-1 mutation of Arabidopsis thaliana confers resistance to the plant hormones auxin, ethylene, and abscisic acid. In addition, axr2-1 has pleiotropic effects on plant morphology which include gravitropic defects in roots, hypocotyls and inflorescences of axr2-1 plants. Two genetic screens were conducted to isolate new mutations at the AXR2 locus. First, axr2-1 pollen was gamma-irradiated, crossed onto wild-type plants, and the M1 progeny screened for loss of the axr2-1 phenotype. Large deletions of the axr2-1 region on chromosome 3 resulted; however, none of these deletions appeared to be heritable. In the second, M2 seed obtained from axr2-1 gl-1 plants was screened for reversion of the axr2-1 phenotype. One revertant line, axr2-r3, has a distinctive phenotype caused by a second mutation at the axr2 locus. To learn more about the nature of the axr2-1 mutation, the effects of varying the ratio of wild-type to mutant copies of the AXR2 gene were examined by comparing plants of the following genotypes: +/+, +/+/+, axr2-1/axr2-1, axr2-1/+ and axr2-1/+/+. Additionally, accumulation of transcripts from the auxin-inducible SAUR-AC1 gene was examined to determine the response of wild-type and mutant plants to auxin. Wild-type seedlings and mature plants accumulate transcripts with auxin treatment. In contrast, axr2-1 tissue does not accumulate SAUR-AC1 transcripts in response to auxin. Taken together, these results indicate that axr2-1 is a neomorphic or hypermorphic mutation that disrupts an early step in an auxin response pathway.