Identification of blocks in chlorophyll biosynthetic pathway in chlorophyll-deficient mutants of Pennisetum glaucum (L.) R. Br

摘要

Blocks in the chlorophyll biosynthetic pathway among different chlorophyll-deficient phenotypes of Pennisetum glaucum were investigated employing 77 K fluorescence spectroscopy. Green seedlings from yellow/white stripe mutants and an albino mutant showed emission maxima at 657, 685 and 733 nm corresponding to protochlorophyllide (pchlide), photosystem II and photosystem I, respectively. Yellow seedlings showed peaks at 657 nm and 678 nm corresponding to pchlide and chlorophyllide (chlide), respectively, indicating a block in the reduction of chlide, whereas the white seedlings and albino accumulated pchlide, suggesting an impairment in the photoreduction of pchlide. Of the four loci identified, vi3 and vi4 block the conversion of pchlide to chl(ide), whereas the conversion of chlide to chlorophyll is under the control of vi1 and vi2 loci.