Abstract
The shape and color of flowers are important for plant reproduction because they attract pollinators such as insects and birds. Therefore, it is thought that alterations in these traits may result in the attraction of different pollinators, genetic isolation, and ultimately, (sympatric) speciation. Petunia integrifolia and P. axillaris bear flowers with different shapes and colors that appear to be visited by different insects. The anthocyanin2 (an2) locus, a regulator of the anthocyanin biosynthetic pathway, is the main determinant of color differences. Here, we report an analysis of molecular events at the an2 locus that occur during Petunia spp evolution. We isolated an2 by transposon tagging and found that it encodes a MYB domain protein, indicating that it is a transcription factor. Analysis of P. axillaris subspecies with white flowers showed that they contain an2(-) alleles with two alternative frameshifts at one site, apparently caused by the insertion and subsequent excision of a transposon. A third an2(-) allele has a nonsense mutation elsewhere, indicating that it arose independently. The distribution of polymorphisms in an2(-) alleles suggests that the loss of an2 function and the consequent changes in floral color were not the primary cause for genetic separation of P. integrifolia and P. axillaris. Rather, they were events that occurred late in the speciation process, possibly to reinforce genetic isolation and complete speciation.
Full Text
The Full Text of this article is available as a PDF (380.7 KB).
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Alfenito M. R., Souer E., Goodman C. D., Buell R., Mol J., Koes R., Walbot V. Functional complementation of anthocyanin sequestration in the vacuole by widely divergent glutathione S-transferases. Plant Cell. 1998 Jul;10(7):1135–1149. doi: 10.1105/tpc.10.7.1135. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Beld M., Martin C., Huits H., Stuitje A. R., Gerats A. G. Flavonoid synthesis in Petunia hybrida: partial characterization of dihydroflavonol-4-reductase genes. Plant Mol Biol. 1989 Nov;13(5):491–502. doi: 10.1007/BF00027309. [DOI] [PubMed] [Google Scholar]
- Coen E. S., Carpenter R., Martin C. Transposable elements generate novel spatial patterns of gene expression in Antirrhinum majus. Cell. 1986 Oct 24;47(2):285–296. doi: 10.1016/0092-8674(86)90451-4. [DOI] [PubMed] [Google Scholar]
- Cone K. C., Cocciolone S. M., Burr F. A., Burr B. Maize anthocyanin regulatory gene pl is a duplicate of c1 that functions in the plant. Plant Cell. 1993 Dec;5(12):1795–1805. doi: 10.1105/tpc.5.12.1795. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Coyne J. A. Genetics and speciation. Nature. 1992 Feb 6;355(6360):511–515. doi: 10.1038/355511a0. [DOI] [PubMed] [Google Scholar]
- Doebley J., Lukens L. Transcriptional regulators and the evolution of plant form. Plant Cell. 1998 Jul;10(7):1075–1082. doi: 10.1105/tpc.10.7.1075. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Doebley J., Stec A., Hubbard L. The evolution of apical dominance in maize. Nature. 1997 Apr 3;386(6624):485–488. doi: 10.1038/386485a0. [DOI] [PubMed] [Google Scholar]
- Gerats A. G., Huits H., Vrijlandt E., Maraña C., Souer E., Beld M. Molecular characterization of a nonautonomous transposable element (dTph1) of petunia. Plant Cell. 1990 Nov;2(11):1121–1128. doi: 10.1105/tpc.2.11.1121. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Goff S. A., Cone K. C., Chandler V. L. Functional analysis of the transcriptional activator encoded by the maize B gene: evidence for a direct functional interaction between two classes of regulatory proteins. Genes Dev. 1992 May;6(5):864–875. doi: 10.1101/gad.6.5.864. [DOI] [PubMed] [Google Scholar]
- Goodrich J., Carpenter R., Coen E. S. A common gene regulates pigmentation pattern in diverse plant species. Cell. 1992 Mar 6;68(5):955–964. doi: 10.1016/0092-8674(92)90038-e. [DOI] [PubMed] [Google Scholar]
- Grotewold E., Athma P., Peterson T. Alternatively spliced products of the maize P gene encode proteins with homology to the DNA-binding domain of myb-like transcription factors. Proc Natl Acad Sci U S A. 1991 Jun 1;88(11):4587–4591. doi: 10.1073/pnas.88.11.4587. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Hanson M. A., Gaut B. S., Stec A. O., Fuerstenberg S. I., Goodman M. M., Coe E. H., Doebley J. F. Evolution of anthocyanin biosynthesis in maize kernels: the role of regulatory and enzymatic loci. Genetics. 1996 Jul;143(3):1395–1407. doi: 10.1093/genetics/143.3.1395. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Holton T. A., Cornish E. C. Genetics and Biochemistry of Anthocyanin Biosynthesis. Plant Cell. 1995 Jul;7(7):1071–1083. doi: 10.1105/tpc.7.7.1071. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Huits H. S., Gerats A. G., Kreike M. M., Mol J. N., Koes R. E. Genetic control of dihydroflavonol 4-reductase gene expression in Petunia hybrida. Plant J. 1994 Sep;6(3):295–310. doi: 10.1046/j.1365-313x.1994.06030295.x. [DOI] [PubMed] [Google Scholar]
- Kranz H. D., Denekamp M., Greco R., Jin H., Leyva A., Meissner R. C., Petroni K., Urzainqui A., Bevan M., Martin C. Towards functional characterisation of the members of the R2R3-MYB gene family from Arabidopsis thaliana. Plant J. 1998 Oct;16(2):263–276. doi: 10.1046/j.1365-313x.1998.00278.x. [DOI] [PubMed] [Google Scholar]
- Kroon J., Souer E., de Graaff A., Xue Y., Mol J., Koes R. Cloning and structural analysis of the anthocyanin pigmentation locus Rt of Petunia hybrida: characterization of insertion sequences in two mutant alleles. Plant J. 1994 Jan;5(1):69–80. doi: 10.1046/j.1365-313x.1994.5010069.x. [DOI] [PubMed] [Google Scholar]
- Lloyd A. M., Walbot V., Davis R. W. Arabidopsis and Nicotiana anthocyanin production activated by maize regulators R and C1. Science. 1992 Dec 11;258(5089):1773–1775. doi: 10.1126/science.1465611. [DOI] [PubMed] [Google Scholar]
- Ludwig S. R., Wessler S. R. Maize R gene family: tissue-specific helix-loop-helix proteins. Cell. 1990 Sep 7;62(5):849–851. doi: 10.1016/0092-8674(90)90259-h. [DOI] [PubMed] [Google Scholar]
- Marrs K. A., Alfenito M. R., Lloyd A. M., Walbot V. A glutathione S-transferase involved in vacuolar transfer encoded by the maize gene Bronze-2. Nature. 1995 Jun 1;375(6530):397–400. doi: 10.1038/375397a0. [DOI] [PubMed] [Google Scholar]
- Martin C., Gerats T. Control of Pigment Biosynthesis Genes during Petal Development. Plant Cell. 1993 Oct;5(10):1253–1264. doi: 10.1105/tpc.5.10.1253. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Martin C., Paz-Ares J. MYB transcription factors in plants. Trends Genet. 1997 Feb;13(2):67–73. doi: 10.1016/s0168-9525(96)10049-4. [DOI] [PubMed] [Google Scholar]
- Martin C., Prescott A., Mackay S., Bartlett J., Vrijlandt E. Control of anthocyanin biosynthesis in flowers of Antirrhinum majus. Plant J. 1991 Jul;1(1):37–49. doi: 10.1111/j.1365-313x.1991.00037.x. [DOI] [PubMed] [Google Scholar]
- Moyano E., Martínez-Garcia J. F., Martin C. Apparent redundancy in myb gene function provides gearing for the control of flavonoid biosynthesis in antirrhinum flowers. Plant Cell. 1996 Sep;8(9):1519–1532. doi: 10.1105/tpc.8.9.1519. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Paz-Ares J., Ghosal D., Wienand U., Peterson P. A., Saedler H. The regulatory c1 locus of Zea mays encodes a protein with homology to myb proto-oncogene products and with structural similarities to transcriptional activators. EMBO J. 1987 Dec 1;6(12):3553–3558. doi: 10.1002/j.1460-2075.1987.tb02684.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Quattrocchio F., Wing J. F., Leppen HTC., Mol JNM., Koes R. E. Regulatory Genes Controlling Anthocyanin Pigmentation Are Functionally Conserved among Plant Species and Have Distinct Sets of Target Genes. Plant Cell. 1993 Nov;5(11):1497–1512. doi: 10.1105/tpc.5.11.1497. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Quattrocchio F., Wing J. F., van der Woude K., Mol J. N., Koes R. Analysis of bHLH and MYB domain proteins: species-specific regulatory differences are caused by divergent evolution of target anthocyanin genes. Plant J. 1998 Feb;13(4):475–488. doi: 10.1046/j.1365-313x.1998.00046.x. [DOI] [PubMed] [Google Scholar]
- Renckens S., De Greve H., Beltrán-Herrera J., Toong L. T., Deboeck F., De Rycke R., Van Montagu M., Hernalsteens J. P. Insertion mutagenesis and study of transposable elements using a new unstable virescent seedling allele for isolation of haploid petunia lines. Plant J. 1996 Sep;10(3):533–544. doi: 10.1046/j.1365-313x.1996.10030533.x. [DOI] [PubMed] [Google Scholar]
- Sablowski R. W., Moyano E., Culianez-Macia F. A., Schuch W., Martin C., Bevan M. A flower-specific Myb protein activates transcription of phenylpropanoid biosynthetic genes. EMBO J. 1994 Jan 1;13(1):128–137. doi: 10.1002/j.1460-2075.1994.tb06242.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sainz M. B., Grotewold E., Chandler V. L. Evidence for direct activation of an anthocyanin promoter by the maize C1 protein and comparison of DNA binding by related Myb domain proteins. Plant Cell. 1997 Apr;9(4):611–625. doi: 10.1105/tpc.9.4.611. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Snowden K. C., Napoli C. A. Psl: a novel Spm-like transposable element from Petunia hybrida. Plant J. 1998 Apr;14(1):43–54. doi: 10.1046/j.1365-313x.1998.00098.x. [DOI] [PubMed] [Google Scholar]
- Solano R., Nieto C., Avila J., Cañas L., Diaz I., Paz-Ares J. Dual DNA binding specificity of a petal epidermis-specific MYB transcription factor (MYB.Ph3) from Petunia hybrida. EMBO J. 1995 Apr 18;14(8):1773–1784. doi: 10.1002/j.1460-2075.1995.tb07166.x. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Souer E., Quattrocchio F., de Vetten N., Mol J., Koes R. A general method to isolate genes tagged by a high copy number transposable element. Plant J. 1995 Apr;7(4):677–685. doi: 10.1046/j.1365-313x.1995.7040677.x. [DOI] [PubMed] [Google Scholar]
- Souer E., van der Krol A., Kloos D., Spelt C., Bliek M., Mol J., Koes R. Genetic control of branching pattern and floral identity during Petunia inflorescence development. Development. 1998 Feb;125(4):733–742. doi: 10.1242/dev.125.4.733. [DOI] [PubMed] [Google Scholar]
- Weisshaar B., Jenkins G. I. Phenylpropanoid biosynthesis and its regulation. Curr Opin Plant Biol. 1998 Jun;1(3):251–257. doi: 10.1016/s1369-5266(98)80113-1. [DOI] [PubMed] [Google Scholar]
- Williams C. E., Grotewold E. Differences between plant and animal Myb domains are fundamental for DNA binding activity, and chimeric Myb domains have novel DNA binding specificities. J Biol Chem. 1997 Jan 3;272(1):563–571. doi: 10.1074/jbc.272.1.563. [DOI] [PubMed] [Google Scholar]
- de Vetten N., Quattrocchio F., Mol J., Koes R. The an11 locus controlling flower pigmentation in petunia encodes a novel WD-repeat protein conserved in yeast, plants, and animals. Genes Dev. 1997 Jun 1;11(11):1422–1434. doi: 10.1101/gad.11.11.1422. [DOI] [PubMed] [Google Scholar]
- van Hoof A., Green P. J. Premature nonsense codons decrease the stability of phytohemagglutinin mRNA in a position-dependent manner. Plant J. 1996 Sep;10(3):415–424. doi: 10.1046/j.1365-313x.1996.10030415.x. [DOI] [PubMed] [Google Scholar]
- van Houwelingen A., Souer E., Mol J., Koes R. Epigenetic interactions among three dTph1 transposons in two homologous chromosomes activate a new excision-repair mechanism in petunia. Plant Cell. 1999 Jul;11(7):1319–1336. doi: 10.1105/tpc.11.7.1319. [DOI] [PMC free article] [PubMed] [Google Scholar]
- van Houwelingen A., Souer E., Spelt K., Kloos D., Mol J., Koes R. Analysis of flower pigmentation mutants generated by random transposon mutagenesis in Petunia hybrida. Plant J. 1998 Jan;13(1):39–50. doi: 10.1046/j.1365-313x.1998.00005.x. [DOI] [PubMed] [Google Scholar]
- van Tunen A. J., Mur L. A., Recourt K., Gerats A. G., Mol J. N. Regulation and manipulation of flavonoid gene expression in anthers of petunia: the molecular basis of the Po mutation. Plant Cell. 1991 Jan;3(1):39–48. doi: 10.1105/tpc.3.1.39. [DOI] [PMC free article] [PubMed] [Google Scholar]
