Casas-Flores Sergio, Rios-Momberg Mauricio, Bibbins Martha, Ponce-Noyola Patricia, Herrera-Estrella Alfredo
Departamento de Ingeniería Genética de Plantas, CINVESTAV Unidad Irapuato, Apartado postal 629, Irapuato 36500, Mexico.
Instituto de Investigación en Biología Experimental, Facultad de Química, Universidad de Guanajuato, Apartado postal 187, Guanajuato 36050, Mexico.
Microbiology (Reading). 2004 Nov;150(Pt 11):3561-3569. doi: 10.1099/mic.0.27346-0.
In fungi, phototropism, the induction of carotenogenesis and reproductive structures, and resetting of the circadian rhythm are controlled by blue light. Trichoderma atroviride, a fungus used in biological control, sporulates in a synchronized manner following a brief pulse of blue light. Due to its apparent simplicity, this response was chosen for pursuing photoreceptor isolation. Two genes were cloned, blue-light regulators 1 and 2 (blr-1 and blr-2), similar to the Neurospora crassa white-collar 1 and 2, respectively. The BLR-1 protein has all the characteristics of a blue-light photoreceptor, whereas the structure of the deduced BLR-2 protein suggests that it interacts with BLR-1 through PAS domains to form a complex. Disruption of the corresponding genes demonstrated that they are essential for blue-light-induced conidiation. blr-1 and blr-2 were also shown to be essential for the light-induced expression of the photolyase-encoding gene (phr-1). Mechanical injury of mycelia was found to trigger conidiation of T. atroviride, a response not described previously. This response was not altered in the mutants. A novel effect of both red and blue light on mycelial growth was found involving another light receptor, which is compensated by the BLR proteins.
在真菌中，向光性、类胡萝卜素生成及生殖结构的诱导以及昼夜节律的重置均受蓝光控制。绿色木霉是一种用于生物防治的真菌，在短暂的蓝光脉冲后会同步产孢。由于其反应看似简单，因此被选来进行光受体的分离研究。克隆出了两个基因，蓝光调节因子1和2（blr-1和blr-2），它们分别与粗糙脉孢菌的白领1和白领2相似。BLR-1蛋白具备蓝光光受体的所有特征，而推导得出的BLR-2蛋白结构表明它通过PAS结构域与BLR-1相互作用形成复合物。相应基因的破坏表明它们对于蓝光诱导的分生孢子形成至关重要。blr-1和blr-2对于光解酶编码基因（phr-1）的光诱导表达也必不可少。发现菌丝体的机械损伤会触发绿色木霉的分生孢子形成，这是此前未描述过的一种反应。这种反应在突变体中未发生改变。发现红光和蓝光对菌丝体生长均有新的影响，涉及另一种光受体，而这种影响会被BLR蛋白补偿。
