Molecular Characterization of G protein Responsive Gene Expression in Arabidopsis

Abstract

In conclusion, transcriptome analysis of the gcr1-5 mutant showed for the first time that a) GCR1 newlinehas an extensive genomewide response, revealing many hitherto unknown genes and processes newlineincluding, but not limited to those regulated by the known G-proteins in Arabidopsis; b) some of newlineits roles, such as in biotic and abiotic stress, hormone response and secondary metabolism are newlineamong those regulated by the known heterotrimeric G-proteins; and c) GCR1 also has other newlineimportant roles that are either independent of, or hitherto unattributed to G-protein signalling, such newlineas in phosphate starvation, storage compound and fatty acid biosynthesis, cell fate etc., though the newlinepossibility of some of them being regulated by other yet-to-be identified G-proteins or their newlinecomponents cannot be ruled out. newlineSimilarly, microarray analysis of the gpa1-5 mutant showed the extensive genomewide role of newlineGPA1 in Arabidopsis, in regulating at least 394 genes belonging to over 79 processes/pathways, newlineand revealing many hitherto unknown roles of GPA1 and plant heterotrimeric G-proteins in newlinegeneral, well beyond those reported by signal-specific or response-specific approaches. More newlineimportantly, the identical regulation of 114 genes in the GPA1 and GCR1 mutants, constituting newlineeven higher commonality at the process level, has been revealed for the first time. In other words, newlineGCR1 and GPA1 regulate not only some common genes, but also different genes belonging to the newlinesame pathways to achieve similar regulatory outcomes, apart from playing some totally newlineindependent roles. Many of these regulatory roles have potential agronomic significance, such as newlinestress and nutrient response, which merit further attention. Thus, our study not only provides the newlinemost comprehensive understanding of the organism-wide role of GPA1, but also its partial overlap newlinewith the role of GCR1 in plant heterotrimeric G-protein signalling. This is further confirmed by newlinemicroarray analysis of the double mutant and its comparison with those of the single mutants, newlinewhich revealed not ....