An Arabidopsis mutant tolerant to lethal ultraviolet-B levels shows constitutively elevated accumulation of flavonoids and other phenolics
An Arabidopsis mutant tolerant to lethal ultraviolet-B levels shows constitutively elevated accumulation of flavonoids and other phenolics
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DOI：
10.1104/pp.126.3.1105
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发表时间：
2001-07-01
期刊：
影响因子：
7.4
通讯作者：
Lois, R
中科院分区：
文献类型：
--
作者：
Bieza, K;Lois, R
对紫外线 (UV) 辐射过敏的突变体的分离和表征已成为了解保护植物免受紫外线损伤的机制的有力工具。为了加深对 UVB 辐射防御的各种机制的了解，我们寻找能够提高拟南芥植物对 UV 辐射耐受水平的突变。我们描述了一种单基因显性突变（uvt1），它导致对 WE 辐射条件的显着耐受性，从而杀死野生型植物。色素分析显示，uvt1 中紫外线吸收化合物积累的持续增加，增加了叶子阻挡 UVB 辐射的能力，因此可能是该突变体对 UVB 辐射抵抗力增强的原因。紫外线区域吸收的增加至少部分归因于类黄酮和芥子酸积累的增加。 uvt1 植物中查尔酮合酶 (CHS) mRNA 的表达持续升高，表明吸收的增加可能是基因表达变化的结果。 uvt1 中 CHS 的表达仍可被紫外线诱导，表明 uvt1 损伤可能不会影响紫外线介导的 CHS 基因表达调节。我们的数据支持紫外线屏蔽在全面保护植物免受 UVB 辐射方面的重要作用。 uvt1突变体可能被证明是一个重要的工具，可以进一步阐明紫外线吸收色素在紫外线防护中的确切作用，以及其他机制对植物对紫外线辐射的总体耐受性的相对贡献。
The isolation and characterization of mutants hypersensitive to ultraviolet (UV) radiation has been a powerful tool to learn about the mechanisms that protect plants against UV-induced damage. To increase our understanding of the various mechanisms of defense against UVB radiation, we searched for mutations that would increase the level of tolerance of Arabidopsis plants to UV radiation. We describe a single gene dominant mutation (uvt1) that leads to a remarkable tolerance to WE radiation conditions that would kill wild-type plants. Pigment analyses show a constitutive increase in accumulation of UV-absorbing compounds in uvt1 that increases the capacity of the leaves to block UVB radiation and therefore is likely to be responsible for the elevated resistance of this mutant to UVB radiation. These increases in absorption in the UV region are due, at least in part, to increases in flavonoid and sinapate accumulation. Expression of chalcone synthase (CHS) mRNA was shown to be constitutively elevated in uvt1 plants, suggesting that the increases in absorption may be a consequence of changes in gene expression. Expression of CHS in uvt1 was shown to be still inducible by UV, indicating that the uvt1 lesion may not affect the UV-mediated regulation of CHS gene expression. Our data support an important role for UV screens in the overall protection of plants to UVB radiation. The uvt1 mutant could prove to be an important tool to elucidate further the exact role of UV-absorbing pigments in UV protection as well as the relative contribution of other mechanisms to the overall tolerance of plants to UV radiation.