Adaptive melanin response of the soil fungus Aspergillus niger to UV radiation stress at "Evolution Canyon", Mount Carmel, Israel.
Adaptive melanin response of the soil fungus Aspergillus niger to UV radiation stress at "Evolution Canyon", Mount Carmel, Israel.
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DOI：
10.1371/journal.pone.0002993
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发表时间：
2008-08-20
期刊：
影响因子：
3.7
通讯作者：
Nevo E
中科院分区：
文献类型：
--
作者：
Singaravelan N;Grishkan I;Beharav A;Wakamatsu K;Ito S;Nevo E
适应是一个进化过程，在这个过程中，种群的特征通过自然选择进行调整，以更好地应对当地环境带来的挑战。关于自然选择的主要讨论涉及描绘一个可能的适应性性状和产生它的选择因子之间的因果关系。因此，有必要确定直接响应选择而进化的性状，从而增强生物体的适应性。以色列的“进化峡谷”（EC）反映了整个生命的微观进化系统，是研究自然选择和局部适应的理想选择，在急剧，小气候不同的环境。朝南的、热带的、阳光充足的和干旱的“非洲”斜坡（AS）比朝北的、温带的、阴凉的和中温带的“欧洲”斜坡（ES）接收到高200%-800%的太阳辐射，相距200米。因此，太阳紫外辐射（UVR）是一个主要的选择剂在EC影响生物-环境相互作用。黑色素是一种假设已经进化用于微生物中的UV屏蔽的性状。在这里，我们调查的原因和影响之间的关系差异紫外线辐射对EC和丝状土壤真菌尼日尔曲霉的孢子黑色素浓度的相对斜坡。我们测试了AS菌株比ES菌株表现出更高的黑色素含量导致更高的UV抗性的工作假设。用分光光度计测定了80个菌株分生孢子的黑色素含量。结果表明，AS菌株分生孢子平均黑色素含量是ES菌株的3倍，且AS菌株的抗UVA能力强于ES菌株。黑色素在分生孢子中的含量比较。尼日尔菌株从阳光和阴暗的微生境主要是阳光AS和主要是阴暗ES表明，阴影条件下的AS对黑色素的选择没有影响，相反，阳光菌株从ES显示较高的黑色素浓度。我们认为A.尼日尔是自然选择产生的一种对紫外线辐射的适应性性状。
Adaptation is an evolutionary process in which traits in a population are tailored by natural selection to better meet the challenges presented by the local environment. The major discussion relating to natural selection concerns the portraying of the cause and effect relationship between a presumably adaptive trait and selection agents generating it. Therefore, it is necessary to identify trait(s) that evolve in direct response to selection, enhancing the organism's fitness. “Evolution Canyon” (EC) in Israel mirrors a microcosmic evolutionary system across life and is ideal to study natural selection and local adaptation under sharply, microclimatically divergent environments. The south-facing, tropical, sunny and xeric “African” slope (AS) receives 200%–800% higher solar radiation than the north-facing, temperate, shady and mesic “European” slope (ES), 200 meters apart. Thus, solar ultraviolet radiation (UVR) is a major selection agent in EC influencing the organism-environment interaction. Melanin is a trait postulated to have evolved for UV-screening in microorganisms. Here we investigate the cause and effect relationship between differential UVR on the opposing slopes of EC and the conidial melanin concentration of the filamentous soil fungus Aspergillus niger. We test the working hypothesis that the AS strains exhibit higher melanin content than strains from the ES resulting in higher UV resistance. We measured conidial melanin concentration of 80 strains from the EC using a spectrophotometer. The results indicated that mean conidial melanin concentration of AS strains were threefold higher than ES strains and the former resisted UVA irradiation better than the latter. Comparisons of melanin in the conidia of A. niger strains from sunny and shady microniches on the predominantly sunny AS and predominantly shady ES indicated that shady conditions on the AS have no influence on the selection on melanin; in contrast, the sunny strains from the ES displayed higher melanin concentrations. We conclude that melanin in A. niger is an adaptive trait against UVR generated by natural selection.
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影响因子：
3.4
作者：
Newsham, KK;McLeod, AR;Emmett, BA
通讯作者：
Emmett, BA
影响因子：
2
作者：
Goncalves, RDR;Pombeiro-Sponchiado, SR
通讯作者：
Pombeiro-Sponchiado, SR
影响因子：
2.8
作者：
Klich, MA
通讯作者：
Klich, MA
影响因子：
6.5
作者：
OZEKI, H;ITO, S;HIROBE, T
通讯作者：
HIROBE, T
DOI：
10.1098/rspb.1995.0189
发表时间：
1995-11-22
影响因子：
4.7
作者：
NEVO, E
通讯作者：
NEVO, E