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Nicotiana plumbaginifolia hlg mutants have a mutation in a PHYB ‐type phytochrome gene: they have elongated hypocotyls in red light, but are not elongated as adult plants
Author(s) -
Hudson Matthew,
Robson Paul R.H.,
Kraepiel Yvan,
Caboche Michel,
Smith Harry
Publication year - 1997
Publication title -
the plant journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.058
H-Index - 269
eISSN - 1365-313X
pISSN - 0960-7412
DOI - 10.1046/j.1365-313x.1997.12051091.x
Subject(s) - phytochrome , mutant , biology , genetics , far red , hypocotyl , wild type , missense mutation , phytochrome a , microbiology and biotechnology , allele , mutation , gene , botany , arabidopsis , red light
Summary Two new allelic mutants of Nicotiana plumbaginifolia have been isolated which display a hypocotyl which is long ( hlg ) when seedlings are grown in continuous white light (W). This can be accounted for by the decreased response to red light (R) of the hypocotyl elongation rate in these mutants. Responses to other wavelengths are unaffected in the mutants. When grown in white light, mature hlg mutants are not elongated with respect to the wild‐type; they also bolt and flower later. The shade‐avoidance responses to red/far red ratio (R:FR) are intact in these mutants. Both mutants are deficient in a phyB‐like polypeptide that is immunodetectable in the wild‐type; both have wild‐type levels of a phyA‐like polypeptide. These alleles are inherited in a partially dominant manner, and correspond to single‐base missense mutations in a gene highly homologous to N. tabacum PHYB , which codes for a phytochrome B‐type photoreceptor. One allele, hlg‐1 , has an introduced amino acid substitution; this may define a residue essential for phytochrome protein stability. The other allele, hlg‐2 , has a stop codon introduced C‐terminal to the chromophore binding domain. As these phyB mutants are unaffected in shade‐avoidance responses, but deficient in perception of R, it is concluded that the phyB absent in these mutants is responsible for R perception in the N. plumbaginifolia seedling, but is not a R:FR sensor in light‐grown plants.