Departamento de Genética, Universidad de Sevilla, Sevilla, Spain.
PLoS One. 2012;7(3):e33658. doi: 10.1371/journal.pone.0033658. Epub 2012 Mar 20.
The ascomycete fungus Neurospora is present in many parts of the world, in particular in tropical and subtropical areas, where it is found growing on recently burned vegetation. We have sampled the Neurospora population across Spain. The sampling sites were located in the region of Galicia (northwestern corner of the Iberian peninsula), the province of Cáceres, the city of Seville, and the two major islands of the Canary Islands archipelago (Tenerife and Gran Canaria, west coast of Africa). The sites covered a latitude interval between 27.88° and 42.74°. We have identified wild-type strains of N. discreta, N. tetrasperma, N. crassa, and N. sitophila and the frequency of each species varied from site to site. It has been shown that after exposure to light Neurospora accumulates the orange carotenoid neurosporaxanthin, presumably for protection from UV radiation. We have found that each Neurospora species accumulates a different amount of carotenoids after exposure to light, but these differences did not correlate with the expression of the carotenogenic genes al-1 or al-2. The accumulation of carotenoids in Neurospora shows a correlation with latitude, as Neurospora strains isolated from lower latitudes accumulate more carotenoids than strains isolated from higher latitudes. Since regions of low latitude receive high UV irradiation we propose that the increased carotenoid accumulation may protect Neurospora from high UV exposure. In support of this hypothesis, we have found that N. crassa, the species that accumulates more carotenoids, is more resistant to UV radiation than N. discreta or N. tetrasperma. The photoprotection provided by carotenoids and the capability to accumulate different amounts of carotenoids may be responsible, at least in part, for the distribution of Neurospora species that we have observed across a range of latitudes.
有生质体的真菌 Neurospora 存在于世界上许多地方，特别是在热带和亚热带地区，在那里可以在最近燃烧过的植被上发现它。我们对西班牙的 Neurospora 种群进行了采样。采样地点位于加利西亚地区（伊比利亚半岛的西北角）、卡塞雷斯省、塞维利亚市以及加那利群岛（特内里费岛和大加那利岛，非洲西海岸）的两个主要岛屿。这些地点的纬度间隔在 27.88°和 42.74°之间。我们已经鉴定出了野生型 N. discreta、N. tetrasperma、N. crassa 和 N. sitophila 菌株，并且每种菌株的频率在不同地点有所不同。已经表明，Neurospora 在暴露于光线下会积累橙色类胡萝卜素神经索拉定，大概是为了防止紫外线辐射。我们发现，每种 Neurospora 物种在暴露于光线下后都会积累不同量的类胡萝卜素，但这些差异与类胡萝卜素生成基因 al-1 或 al-2 的表达无关。Neurospora 中类胡萝卜素的积累与纬度有关，因为从较低纬度分离出的 Neurospora 菌株比从较高纬度分离出的菌株积累了更多的类胡萝卜素。由于低纬度地区接收到的紫外线辐射较高，我们提出，类胡萝卜素的积累增加可能保护 Neurospora 免受高 UV 暴露。为了支持这一假说，我们发现，积累更多类胡萝卜素的物种 N. crassa 比 N. discreta 或 N. tetrasperma 对 UV 辐射更具有抗性。类胡萝卜素的光保护作用以及积累不同量类胡萝卜素的能力，可能至少部分解释了我们在不同纬度范围内观察到的 Neurospora 物种的分布。
