Bioinformatics Analysis Of Plant Light Signal Transduction Pathway

Light controls growth and development throughout the plant life cycle. Studies employing model species A. thaliana have elucidated several aspects of photoperception and light signal transduction that control plant development. However, the information available for other species is scarce. In this study, the light signal transduction pathway in higher plants and the networks involved in the photoperiod response were analysized by using bioinformatics methods. 160 target genes releated to the response to blue light, response to red and far red light, Photomorphogenesis and circadian rhythm in A. thaliana were obtained based on gene ontology (GO) annotations. Among them, a total of 46 genes from 20 gene families or the sub-families that are essential in regulation networks were selected to investagate the poplar, grape, medicago and rice completed genome sequence databases so as to identify candidate genes coding for photoperceptor and light signal transduction pathway associated proteins in these plants. 49 candidate genes were identified in poplar, 37 in grape, 27 in medicago and 36 in rice. Some important Arabidopsis phytochrome and cryptochrome signaling components were absent in the protein database of the four species. Furthermore, 19 phylogenetic trees were constructed and the evolution of these gene families were analyzed preliminarily. A light signal transduction pathway of "light perception—signal transduction—downstream physiological response" in the four species is proposed based on the identified key components. These results demonstrate the power of comparative genomics between model species and other crop species to elucidate several aspects of plant physiology and metabolism.