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

Disruption of the 1-deoxy-D-xylulose-5-phosphate reductoisomerase (DXR) gene results in albino, dwarf and defects in trichome initiation and stomata closure in Arabidopsis

“…To gain more insight into the metabolic flux of the MEP pathway, we monitored the transcript changes in the dxr mutants, of those important enzymes involved in the MEP pathway and related isoprenoid biosynthetic pathways. In the albino tissues with reduced DXR transcript level, all the examined genes exhibited reduced transcription, which is similar to the gene expression pattern in the cla1/dxs and pds3 mutants [7,29,30]. This is an interesting phenomenon, since these three enzymes catalyze different steps in the isoprenoid biosynthetic pathways, i.e., DXR and DXS catalyzing the initial two steps of the MEP pathway, and PDS3 catalyzing a down-stream reaction leading to ABA biosynthesis (Figure 1).…”

“…Like the other albino mutants of the enzymes involved in MEP-related biosynthetic pathways, the dxr mutants exhibited an arrest in plastid development at early stages [20,22,30,[46][47][48]. This is consistent with the increased chlorophyll a/ b ratio observed in the pale inflorescence tissues, which are more sensitive to light due to the undeveloped plastids [49].…”

“…This is an interesting phenomenon, since these three enzymes catalyze different steps in the isoprenoid biosynthetic pathways, i.e., DXR and DXS catalyzing the initial two steps of the MEP pathway, and PDS3 catalyzing a down-stream reaction leading to ABA biosynthesis (Figure 1). In pds3 mutant, it was suggested that there might be a feedback control of the transcription of enzymes involved in the isoprenoid biosynthetic pathway by the accumulated phytoene, the substrate for the PDS3 enzyme [30]. This feedback control indirectly led to decreased GA biosynthesis, a branch different from the ABA metabolic pathway.…”

“…Previous pathway always show feedback regulation [30,32]. It was thus reasonable to hypothesize that the same kind of metabolic changes might exist in the dxr mutant or tissues with reduced DXR expression levels.…”

“…Exogenous application of GAs to the medium could partially rescue the dwarf phenotype of the pds3 mutant [30]. Other research indicated that levels of not only GAs but also other important compounds were decreased as a result of the metabolic disruption in the mutants of enzymes involved in the MEP pathway [21,[30][31][32][33][34]. However, no detailed analyses have been [30]).…”