Disruption of phytoene desaturase gene results in albino and dwarf phenotypes in Arabidopsis by impairing chlorophyll, carotenoid, and gibberellin biosynthesis

Carotenoids play an important role in many physiological processes in plants and the phytoene desaturase gene (PDS3)encodes one of the important enzymes in the carotenoid biosynthesis pathway. Here we report the identification andanalysis of a T-DNA insertion mutant of PDS3 gene. Functional complementation confirmed that both the albino anddwarf phenotypes of the pds3 mutant resulted from functional disruption of the PDS3 gene. Chloroplast development wasarrested at the proplastid stage in the pds3 mutant. Further analysis showed that high level of phytoene was accumulatedin the pds3 mutant. Addition of exogenous GAcould partially rescue the dwarf phenotype, suggesting that the dwarfphenotype of the pds3 mutant might be due to GA deficiency. Microarray and RT-PCR analysis showed that disruptingPDS3 gene resulted in gene expression changes involved in at least 20 metabolic pathways, including the inhibition ofmany genes in carotenoid, chlorophyll, and GA biosynthesis pathways. Our data suggest that the accumulated phytoenein the pds3 mutant might play an important role in certain negative feedbacks to affect gene expression of diverse cel-lular pathways.