Putrescine accumulation confers drought tolerance in transgenic Arabidopsis plants over-expressing the homologous Arginine decarboxylase 2 gene
Putrescine accumulation confers drought tolerance in transgenic Arabidopsis plants over-expressing the homologous Arginine decarboxylase 2 gene
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DOI：
10.1016/j.plaphy.2010.02.002
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发表时间：
2010-07-01
影响因子：
6.5
通讯作者：
Altabella, Teresa
中科院分区：
文献类型：
--
作者：
Alcazar, Ruben;Planas, Joan;Altabella, Teresa
在缺乏鸟氨酸脱羧酶途径的模式属拟南芥中，参与多胺生物合成的大多数关键基因都是复制的。这种基因冗余与某些基因异构体参与对特定环境刺激的反应有关。我们先前已经证明，干旱胁迫诱导精氨酸脱羧酶2的表达，而精氨酸脱羧酶1的转录水平保持不变。腐胺的积累和精氨酸脱羧酶活性(EC 4.1.1.19)水平的增加在许多不同的植物系统中都有报道，但这种增加的生物学意义尚不清楚。为了对这些问题有一个新的认识，我们研究了组成表达同源精氨酸脱羧酶2基因的转基因拟南芥对干旱的反应。这些品系含有高水平的腐胺，即使在干旱胁迫下也不会改变亚精胺和精胺的含量。抗旱性试验表明，抗旱性的不同程度与Put含量有关。虽然野生型和转基因植株的气孔数目没有显著差异，但ADC2高表达株系的蒸腾速率和气孔导度降低。这些结果表明，过量生产Put的转基因植株的耐旱性机制之一与减少蒸腾失水有关。(C)2010年爱思唯尔·马森公司。版权所有。
In Arabidopsis, a model genus missing a functional ornithine decarboxylase pathway, most of the key genes involved in polyamine biosynthesis are duplicated. This gene redundancy has been related to the involvement of certain gene isoforms in the response to specific environmental stimuli. We have previously shown that drought stress induces Arginine decarboxlase 2 expression, while transcript levels for Arginine decarboxlase 1 remain constant. Accumulation of putrescine and increased arginine decarboxlase activity (EC 4.1.1.19) levels in response to different abiotic stresses have been reported in many different plant systems, but the biological meaning of this increase remains unclear. To get a new insight into these questions, we have studied the response to drought of transgenic Arabidopsis thaliana lines constitutively expressing the homologous Arginine decarboxlase 2 gene. These lines contain high levels of putrescine with no changes in spermidine and spermine content even under drought stress. Drought tolerance experiments indicate that the different degree of resistance to dehydration correlates with Put content. Although no significant differences were observed in the number of stomata between wild-type and transgenic plants, a reduction in transpiration rate and stomata conductance was observed in the ADC2 over-expressor lines. These results indicate that one of the mechanisms involved in the drought tolerance of transgenic plants over-producing Put is related to a reduction of water loss by transpiration. (C) 2010 Elsevier Masson SAS. All rights reserved.