Abstract
When phytochrome B deficient mutants (phyB mutants) in rice are grown under red light, they elongate their first leave and second leaf sheaths and became pale green seedlings. We have isolated several revertant mutants (phyB suppressor, PBS) from γ-ray mutagenized phyB-3 pool and then analyzed these mutants. Under ultrastructure of red light grown seedlings, chloroplasts in wild type (Norin-8-go) have well developed thylakoid membrane but those in phyB-3 mutant have small chloroplasts with little thylakoid membrane. The revertant mutants of PBS-19 and -25 have well developed chloroplasts and the chloroplasts were filled with a lot of thylakoid membranes. The elongation which were observed in phyB mutants were inhibited in the revertants. Interestingly, bend of second leaf blade was observed even under red light condition although it was not observed in either wild type or phyB mutants.
To identify these mutations, we are taking positional cloning using progeny crossed with phyB-1, which was Nipponbare genotype.
