hoc:: an Arabidopsis mutant overproducing cytokinins and expressing high in vitro organogenic capacity
hoc:: an Arabidopsis mutant overproducing cytokinins and expressing high in vitro organogenic capacity
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DOI：
10.1046/j.1365-313x.2002.01286.x
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发表时间：
2002-05-01
期刊：
影响因子：
7.2
通讯作者：
Sangwan, RS
中科院分区：
文献类型：
--
作者：
Catterou, M;Dubois, F;Sangwan, RS
一种新的拟南芥突变体，名为hoc，被发现具有较高的茎再生能力。HOC位点可能参与细胞分裂素代谢，导致细胞分裂素过量产生。在体外，特殊根外植体在缺乏外源生长调节剂的情况下发育出许多芽。突变体表现出浓密的表型，有多余的莲座和正常的叶分生，这是由于腋窝分生组织发育过早。遗传和分子分析表明，高茎再生和浓密表型是由位于1号染色体上GAPB CAPS标记旁的一个隐性单基因控制的。定位数据和等位基因测试表明，该突变体与其他报道的拟南芥生长调节突变体不具有等位基因。在黑暗中，特殊突变体去黄化，具有短的下胚轴，张开的子叶和真叶。生长调节剂试验表明，突变体在其地上部分和根部积累的细胞分裂素水平分别是野生型植物的2倍和7倍。因此，在特定植物中，内源性细胞分裂素的增加与高器官生成能力和因此的浓密表型有关。因此，hoc是第一个细胞分裂素过量产生的拟南芥突变体，能够在没有外源生长调节剂的情况下自动再生芽。
A novel Arabidopsis thaliana mutant, named hoc , was found to have an high organogenic capacity for shoot regeneration. The HOC locus may be involved in cytokinin metabolism leading to cytokinin-overproduction. In vitro , hoc root explants develop many shoots in the absence of exogenous growth regulators. The mutant displays a bushy phenotype with supernumerary rosettes and with normal phyllotaxy, resulting from precocious axillary meristem development. Genetic and molecular analyses show that the high shoot regeneration and the bushy phenotype are controlled by a recessive single gene, located on chromosome I, next to the GAPB CAPS marker. The mapping data and allelism tests reveal that the hoc mutant is not allelic to other reported Arabidopsis growth-regulator mutants. In darkness the hoc mutant is de-etiolated, with a short hypocotyl, opened cotyledons and true leaves. Growth regulator assays reveal that the mutant accumulates cytokinins at about two- and sevenfold the cytokinin level of wild-type plants in its aerial parts and roots, respectively. Consequently, the elevated amounts of endogenous cytokinins in hoc plants are associated with high organogenic capacity and hence bushy phenotype. Thus hoc is the first cytokinin-overproducing Arabidopsis mutant capable of auto-regenerating shoots without exogenous growth regulators.