Novel light-regulated genes in Trichoderma atroviride: a dissection by cDNA microarrays

• Published in: Microbiology (Society for General Microbiology) Vol. 152; no. 11; pp. 3305 - 3317
• Main Authors: Rosales-Saavedra, T, Esquivel-Naranjo, E. U, Casas-Flores, S, Martinez-Hernandez, P, Ibarra-Laclette, E, Cortes-Penagos, C, Herrera-Estrella, A
• Format: Journal Article
• Language: English
• Published: Reading Soc General Microbiol 01.11.2006; Society for General Microbiology
• Subjects: Biological and medical sciences; Blotting, Northern; DNA, Complementary - genetics; Fundamental and applied biological sciences. Psychology; Gene Expression Profiling; Gene Expression Regulation, Fungal; Genes, Fungal; Growth, nutrition, metabolism, transports, enzymes. Molecular biology; Light; Microbiology; Mycology; Oligonucleotide Array Sequence Analysis; Signal Transduction; Trichoderma - genetics; Trichoderma - metabolism; Trichoderma - radiation effects; Trichoderma atroviride; Fungi; Northern blotting; Trichoderma; Regulation(control); Gene; DNA chip; Fungi Imperfecti; Dissection; Thallophyta
• ISSN: 1350-0872; 1465-2080
• DOI: 10.1099/mic.0.29000-0

1 Departamento de Ingeniería Genética, Cinvestav Campus Guanajuato, Km 9.6 Libramiento Norte Carretera Irapuato-León, Apartado Postal 629, CP 36500, Irapuato, Guanajuato, Mexico 2 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 Correspondence A. Herrera-Estrella aherrera{at}ira.cinvestav.mx 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. Abbreviations: EST, expressed sequence tag; LRE, light-responsive element; WCC, white collar complex The microarray platform used in the experiments reported in this paper, and the corresponding information on the spotted genes, are available through Gene Expression Omnibus (accession no. GPL4189) from NCBI. Present address: Universidad Autónoma de San Luis Potosí, San Luis Potosí, Mexico. Present address: Instituto Potosino de Investigación Científica y Tecnológica, A. C. San Luis Potosí, San Luis Potosí, Mexico. Present address: Escuela de Químico Farmacobiología, Universidad Michoacana de San Nicolás de Hidalgo, Morelia, Mich., Mexico.