Rosales-Saavedra T, Esquivel-Naranjo E U, Casas-Flores S, Martínez-Hernández P, Ibarra-Laclette E, Cortes-Penagos C, Herrera-Estrella A
Departamento de Ingeniería Genética, Cinvestav Campus Guanajuato, Km 9.6 Libramiento Norte Carretera Irapuato-León, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, Mexico.
Laboratorio Nacional de Genómica para la Biodiversidad, Cinvestav Campus Guanajuato, Km 9.6 Libramiento Norte Carretera Irapuato-León, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, Mexico.
Microbiology (Reading). 2006 Nov;152(Pt 11):3305-3317. doi: 10.1099/mic.0.29000-0.
The influence of light on living organisms is critical, not only because of its importance as the main source of energy for the biosphere, but also due to its capacity to induce changes in the behaviour and morphology of nearly all forms of life. The common soil fungus Trichoderma atroviride responds to blue light in a synchronized manner, in time and space, by forming a ring of green conidia at what had been the colony perimeter at the time of exposure (photoconidiation). A putative complex formed by the BLR-1 and BLR-2 proteins in T. atroviride appears to play an essential role as a sensor and transcriptional regulator in photoconidiation. Expression analyses using microarrays containing 1438 unigenes were carried out in order to identify early light response genes. It was found that 2.8 % of the genes were light responsive: 2 % induced and 0.8 % repressed. Expression analysis in blr deletion mutants allowed the demonstration of the occurrence of two types of light responses, a blr-independent response in addition to the expected blr-dependent one, as well as a new role of the BLR proteins in repression of transcription. Exposure of T. atroviride to continuous light helped to establish that the light-responsive genes are subject to photoadaptation. Finally, evidence is provided of red-light-regulated gene expression and a possible crosstalk between the blue and red light signalling pathways.
光对生物的影响至关重要，这不仅是因为它作为生物圈主要能量来源的重要性，还因为它能够诱导几乎所有生命形式的行为和形态发生变化。常见的土壤真菌绿色木霉会以时空同步的方式对蓝光作出反应，在光照时菌落边缘处形成一圈绿色分生孢子（光致产孢）。绿色木霉中由BLR-1和BLR-2蛋白形成的一种假定复合物似乎在光致产孢过程中作为传感器和转录调节因子发挥着重要作用。为了鉴定早期光反应基因，使用包含1438个单基因的微阵列进行了表达分析。结果发现，2.8%的基因对光有反应：2%被诱导，0.8%被抑制。对blr缺失突变体的表达分析表明存在两种类型的光反应，除了预期的blr依赖性反应外，还有一种blr非依赖性反应，以及BLR蛋白在转录抑制中的新作用。将绿色木霉暴露于持续光照下有助于确定光反应基因会发生光适应。最后，提供了红光调节基因表达的证据以及蓝光和红光信号通路之间可能存在的相互作用。
