Flower-specific KNOX phenotype in the orchid Dactylorhiza fuchsii
Issue Date
2012-07-05Subjects
labellumorchids
Dactylorhiza fuchsii
petal shape
KNOX genes
evolution
flower development
petal spur
C200 Botany
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The KNOTTED1-like homeobox (KNOX) genes are best known for maintaining a pluripotent stem-cell population in the shoot apical meristem that underlies indeterminate vegetative growth, allowing plants to adapt their development to suit the prevailing environmental conditions. More recently, the function of the KNOXgene family has been expanded to include additional roles in lateral organ development such as complex leaf morphogenesis, which has come to dominate the KNOX literature. Despite several reports implicating KNOX genes in the development of carpels and floral elaborations such as petal spurs, few authors have investigated the role of KNOX genes in flower development. Evidence is presented here of a flower-specific KNOX function in the development of the elaborate flowers of the orchid Dactylorhiza fuchsii, which have a three-lobed labellum petal with a prominent spur. Using degenerate PCR, four Class I KNOX genes (DfKN1–4) have been isolated, one from each of the four major Class I KNOX subclades and by reverse transcription PCR (RT-PCR), it is demonstrated that DfKNOXtranscripts are detectable in developing floral organs such as the spur-bearing labellum and inferior ovary. Although constitutive expression of the DfKN2 transcript in tobacco produces a wide range of floral abnormalities, including serrated petal margins, extra petal tissue, and fused organs, none of the vegetative phenotypes typical of constitutive KNOX expression were produced. These data are highly suggestive of a role for KNOX expression in floral development that may be especially important in taxa with elaborate flowers.Citation
Box M., Dodsworth S., Rudall P., Bateman R., Glover B. (2012) 'Flower-specific KNOX phenotype in the orchid Dactylorhiza fuchsii', Journal of Experimental Botany, 63 (13), pp.4811-4819.Publisher
Oxford University Press (OUP)Journal
Journal of Experimental BotanyAdditional Links
https://academic.oup.com/jxb/article/63/13/4811/485184Type
ArticleLanguage
enISSN
0022-0957Sponsors
This work was supported by a Biotechnology and Biological Sciences Research Council (BBSRC) doctoral training grant (DTG) studentshipae974a485f413a2113503eed53cd6c53
10.1093/jxb/ers152
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