Dehydrins are highly expressed in overwintering buds and enhance drought and freezing tolerance in Gentiana triflora
Dehydrins are highly expressed in overwintering buds and enhance drought and freezing tolerance in Gentiana triflora
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DOI：
10.1016/j.plantsci.2013.08.012
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发表时间：
2013-12-01
期刊：
影响因子：
5.2
通讯作者：
Takahashi, Hideyuki
中科院分区：
文献类型：
--
作者：
Imamura, Tomohiro;Higuchi, Atsumi;Takahashi, Hideyuki
龙胆，多年生草本植物，产生越冬芽（OWBs）生存寒冷的季节。虽然龙胆草对干旱、寒冷和冰冻有很强的耐受性，但耐受性的分子机制尚不清楚。我们探索了在OWB中比在其他组织中更高表达的基因，并鉴定了两种龙胆属的同源基因，分别表示为GtDHN1和GtDHN2。这些GtDHN具有几个阿坝或脱水响应元件。此外，GtDHN1和GtDHN2的转录本在OWBs的积累在冬季，但在春季之前下降，这表明GtDHNs可能是由脱水胁迫诱导在寒冷时期，并可能作为一种由阿坝介导的胁迫保护剂。同样，培养的龙胆幼苗积累GtDHN转录响应阿坝以及寒冷和干旱胁迫。此外，过表达GtDHN1或GtDHN2的转基因龙胆植株表现出提高的耐寒性和耐旱性。代谢物组分析表明，主要的抗氧化剂，如谷胱甘肽和抗坏血酸积累在所有转基因植株。过表达GtDHNs也影响抗氧化酶，抗坏血酸过氧化物酶和谷胱甘肽过氧化物酶的活性。基于本研究的结果，GtDHNs是由阿坝和脱水胁迫诱导的，并且具有缓解脱水胁迫的能力，可能通过激活抗氧化机制。GtDHN的积累可能是龙胆OWBs冬季生存策略的一部分。(C)2013爱思唯尔爱尔兰有限公司版权所有。
Gentians, herbaceous perennials, produce overwintering buds (OWBs) to survive the cold season. Although gentians are known to have strong stress tolerances against drought, cold and freezing, the molecular mechanisms of tolerance are unclear. We explored genes more highly expressed in OWBs than in other tissues and identified two gentian orthologs of dehydrins, denoted GtDHN1 and GtDHN2. These GtDHNs possess several ABA or dehydration responsive elements. Furthermore, GtDHN1 and GtDHN2 transcripts in OWBs accumulated during the winter but decreased prior to spring, suggesting that GtDHNs may be induced by dehydration stress during cold periods and may act as a stress protectant mediated by ABA. Likewise, cultured gentian plantlets accumulated GtDHN transcripts in response to ABA as well as cold and drought stresses. Moreover, transgenic gentian plantlets overexpressing GtDHN1 or GtDHN2 showed improved cold and drought stress tolerance. Metabolome analysis revealed that major antioxidants such as glutathione and ascorbate were accumulated in all transgenic plantlets. Overexpression of GtDHNs also affected the activities of the antioxidant enzymes, ascorbate peroxidase and glutathione peroxidase. Based on the results of this study, GtDHNs are induced by ABA and dehydration stress and have an ability to alleviate dehydration stress, probably via activating antioxidant mechanisms. Accumulation of GtDHNs may be part of the strategy for winter survival of gentian OWBs. (C) 2013 Elsevier Ireland Ltd. All rights reserved.