Esteban Raquel, Olano José M, Castresana José, Fernández-Marín Beatriz, Hernández Antonio, Becerril José M, García-Plazaola José I
Department of Plant Biology and Ecology, University of Basque Country (UPV/EHU), Bilbao, Spain.
Physiol Plant. 2009 Apr;135(4):379-89. doi: 10.1111/j.1399-3054.2008.01196.x. Epub 2009 Feb 5.
The earliest land photosynthesis would have increased the risk of photo-oxidations and the demand of anti-oxidative protection. In this work, we aimed to determine the evolutionary trends in photoprotection across a wide representation of the plant kingdom and to verify whether the non-ubiquitous lutein-epoxide (Lx) cycle is a polyphyletic or an ancient character. Carotenoids and alpha-tocopherol (alpha-toc) were analysed by HPLC in 266 species. Phylogenetic analyses of the presence of photoprotective compounds and zeaxanthin-epoxidase (ZE) sequences were performed. Violaxanthin-cycle pigments (VAZ) and alpha-toc were taxonomically ubiquitous. Ancient groups showed higher contents of VAZ than vascular plants, while alpha-toc showed the opposite pattern. Lutein-epoxide was present in 45% of the species. It showed a remarkable variation across groups but with a clear increasing trend from algae to basal angiosperms. Lutein-epoxide was also related to woody trait and leaf longevity. No correlation between the presence of Lx and recurrent mutations in ZE sequences, including the duplications, was found. Thus, there is an evolutionary trend to increase the content of alpha-toc and to decrease the total amount of VAZ pigments. Absence of Lx in algae discards an ancestral origin. Present results are also inconsistent with a polyphyletic origin of Lx in angiosperms.
最早的陆地光合作用可能增加了光氧化的风险以及对抗氧化保护的需求。在这项研究中，我们旨在确定整个植物界广泛代表性物种中光保护的进化趋势，并验证非普遍存在的叶黄素环氧化合物（Lx）循环是一个多系特征还是一个古老特征。通过高效液相色谱法（HPLC）分析了266个物种中的类胡萝卜素和α-生育酚（α-toc）。对光保护化合物的存在情况和玉米黄质环氧化酶（ZE）序列进行了系统发育分析。紫黄质循环色素（VAZ）和α-toc在分类学上普遍存在。古老类群的VAZ含量高于维管植物，而α-toc则呈现相反的模式。45%的物种中存在叶黄素环氧化合物。它在不同类群中表现出显著差异，但从藻类到基部被子植物有明显的增加趋势。叶黄素环氧化合物也与木质性状和叶片寿命有关。未发现Lx的存在与ZE序列中的反复突变（包括重复）之间存在相关性。因此，存在增加α-toc含量并减少VAZ色素总量的进化趋势。藻类中不存在Lx排除了其起源于祖先的可能性。目前的结果也与被子植物中Lx的多系起源不一致。
