The distribution of protochlorophyllide and chlorophyll within seedlings of the lip1 mutant of Pea.
The distribution of protochlorophyllide (Pchlide) and NADPH-Pchlide oxidoreductase (POR) was characterized in the epicotyls and roots of wild-type pea (Pisum sativum L. cv. Alaska) and lip1, a mutant with light-independent photomorphogenesis caused by a mutation in the COP1 locus. The upper part of the dark-grown lip1 mutant epicotyls had a high Pchlide content that decreased downward the organ. The elevated Pchlide level in lip1 seedlings was a result of the differentiation of more proplastids into Pchlide-containing plastids. The cortex cells in the lip1 epicotyl were filled with such plastids in contrast to the cortex cells of wild-type seedlings. The mutant also developed Pchlide-containing plastids in the roots, indicating the suppressing effect of the COP1 locus on development of plastids in the corresponding tissues in dark-grown wild-type plants. The distribution of Pchlide-containing plastids in dark-grown lip1 mutant stem and root was similar to the distribution of chloroplasts in irradiated wild-type plants. Both wild-type and lip1 epicotyls contained mostly short wavelength Pchlide fluorescing at 631 nm with only a small shoulder at 654 nm, which was transformed to a minute amount of chlorophyllide (Chlide) by flash irradiation. In contrast, with continuous irradiation a considerable amount of Chlide was formed especially in the lip1 epicotyls. Immunoblots indicated the presence of POR, as a 36 kDa band, in epicotyls of both dark-grown wild-type and lip1 mutant seedlings. However, lip1 stem tissue had a higher content of POR than the wild-type pea. The high content of POR was unexpected as lip1 lacked both the 654 nm fluorescing Pchlide form and the regular PLBs. In light, a significant amount of chlorophyll was formed also in the roots of the lip1 seedlings.
Seyedi
M
M
Department of Plant Physiology, Botanical Institute, Göteborg University, Box 461, SE-405 30 Göteborg, Sweden. mahdi.seyedi@molbio.gu.se
Timko
M P
MP
Sundqvist
C
C
D029681:Arabidopsis Proteins; D002352:Carrier Proteins / Q000378:metabolism; D002734:Chlorophyll / Q000378:metabolism*; D002735:Chlorophyllides / Q000378:metabolism; D003624:Darkness; D009154:Mutation; D010088:Oxidoreductases / Q000096:biosynthesis; D044925:Oxidoreductases Acting on CH-CH Group Donors; D018532:Pisum sativum / Q000201:enzymology / Q000235:genetics / Q000378:metabolism*; D010940:Plant Proteins / Q000378:metabolism; D018517:Plant Roots / Q000201:enzymology; D018547:Plant Stems / Q000201:enzymology; D018087:Plastids / Q000502:physiology; D011521:Protochlorophyllide / Q000378:metabolism*; D012639:Seeds; D013057:Spectrum Analysis; D044767:Ubiquitin-Protein Ligases
D029681:Arabidopsis Proteins; D002352:Carrier Proteins; D002735:Chlorophyllides; D010940:Plant Proteins; D002734:Chlorophyll; D011521:Protochlorophyllide; D010088:Oxidoreductases; D044925:Oxidoreductases Acting on CH-CH Group Donors; C023886:protochlorophyllide reductase; C471983:AT2G32950 protein, Arabidopsis; D044767:Ubiquitin-Protein Ligases