Abstract:
Zostera marina, a critical keystone marine angiosperm species in coastal seagrass meadows, possesses a photosensitive oxygen evolving complex (OEC). In harsh environments, the photoinactivation of the Z. marina OEC may lead to population declines. However, the factors underlying this photosensitivity remain unclear. Therefore, this study was undertaken to elucidate the elements contributing to Z. marina OEC photosensitivity. Our results demonstrated a gradual decrease in photosystem II performance towards shorter wavelengths, especially blue light and ultraviolet radiation. This phenomenon was characterized by a reduction in Fv/Fm and the rate of O2 evolution, as well as increased fluorescence at 0.3 ms on the OJIP curve. Furthermore, exposure to shorter light wavelengths and longer exposure durations significantly reduced the relative abundance of the OEC peripheral proteins, indicating OEC inactivation. Analyses of light-screening substances revealed that carotenoids, which increased most notably under 420 nm light, might primarily serve as thermal dissipators instead of efficient light filters. In contrast, anthocyanins reacted least to short-wavelength light, in terms of changes to both their content and the expression of genes related to their biosynthesis. Additionally, the levels of aromatically acylated anthocyanins remained consistent across blue-, white-, and red-light treatments. These findings suggest that OEC photoinactivation in Z. marina may be linked to inadequate protection against short-wavelength light, a consequence of insufficient synthesis and aromatic acylation modification of anthocyanins.
摘要:
ZosteraMarina,沿海海草草甸中的关键关键海洋被子植物物种,具有光敏析氧络合物(OEC)。在恶劣的环境中,Z.MarinaOEC的光失活可能导致种群减少。然而,这种光敏性的潜在因素仍不清楚.因此,进行这项研究是为了阐明导致Z.marinaOEC光敏性的因素。我们的结果表明,光系统II的性能逐渐降低到更短的波长,尤其是蓝光和紫外线。这种现象的特征是Fv/Fm和O2释放速率的降低,以及OJIP曲线上0.3ms处的荧光增加。此外,暴露于较短的光波长和较长的暴露持续时间显着降低了OEC外周蛋白的相对丰度,指示OEC失活。光筛选物质的分析表明,类胡萝卜素,在420nm光下最显著地增加,可能主要用作散热器,而不是有效的滤光器。相比之下,花青素对短波长光的反应最小,就其含量和与其生物合成相关的基因表达的变化而言。此外,芳香酰化花青素的水平在整个蓝色中保持一致-,白色-,和红光治疗。这些发现表明,Z.marina中的OEC光失活可能与对短波长光的保护不足有关,花色苷合成不足和芳香酰化修饰的结果。