RRC ID 10835
Author Yamaguchi T, Fukada-Tanaka S, Inagaki Y, Saito N, Yonekura-Sakakibara K, Tanaka Y, Kusumi T, Iida S.
Title Genes encoding the vacuolar Na+/H+ exchanger and flower coloration.
Journal Plant Cell Physiol
Abstract Vacuolar pH plays an important role in flower coloration: an increase in the vacuolar pH causes blueing of flower color. In the Japanese morning glory (Ipomoea nil or Pharbitis nil), a shift from reddish-purple buds to blue open flowers correlates with an increase in the vacuolar pH. We describe details of the characterization of a mutant that carries a recessive mutation in the Purple (Pr) gene encoding a vacuolar Na+/H+ exchanger termed InNHX1. The genome of I. nil carries one copy of the Pr (or InNHX1) gene and its pseudogene, and it showed functional complementation to the yeast nhx1 mutation. The mutant of I. nil, called purple (pr), showed a partial increase in the vacuolar pH during flower-opening and its reddish-purple buds change into purple open flowers. The vacuolar pH in the purple open flowers of the mutant was significantly lower than that in the blue open flowers. The InNHX1 gene is most abundantly expressed in the petals at around 12 h before flower-opening, accompanying the increase in the vacuolar pH for the blue flower coloration. No such massive expression was observed in the petunia flowers. Since the NHX1 genes that promote the transport of Na+ into the vacuoles have been regarded to be involved in salt tolerance by accumulating Na+ in the vacuoles, we can add a new biological role for blue flower coloration in the Japanese morning glory by the vacuolar alkalization.
Volume 42(5)
Pages 451-61
Published 2001-5-1
DOI 10.1093/pcp/pce080
PMID 11382810
MeSH Biological Transport Gene Expression Regulation, Plant Hydrogen-Ion Concentration Molecular Sequence Data Mutation Phylogeny Pigmentation / genetics Plant Proteins / genetics Plants / drug effects Plants / genetics* RNA, Messenger / drug effects RNA, Messenger / genetics RNA, Messenger / metabolism Sequence Alignment Sequence Analysis, DNA Sodium Chloride / pharmacology Sodium-Hydrogen Exchangers / genetics* Sodium-Hydrogen Exchangers / metabolism Vacuoles / metabolism
IF 4.062
Times Cited 133
Morning Glory AK33 AK71 AK72