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Planta

Title:		Evolution of proteinase inhibitor defenses in North American allopolyploid species of Nicotiana
Author(s):		Wu J; Hettenhausen C; Baldwin IT;
Address:		"Department of Molecular Ecology, Max-Planck-Institute for Chemical Ecology, Beutenberg Campus, Hans-Knoll Strasse 8, 07745, Jena, Germany"
Journal Title:		Planta
Year:		2006
Volume:		20060314
Issue:		4
Page Number:		750 - 760
DOI:		10.1007/s00425-006-0256-6
ISSN/ISBN:		0032-0935 (Print) 0032-0935 (Linking)
Abstract:		"We studied the jasmonate (JA)-elicited trypsin-proteinase inhibitor (TPI) anti-herbivore defense system in North American Nicotiana to understand how complex polygenetic traits evolve after allopolyploidy speciation. N. quadrivalvis (Nq) and N. clevelandii (Nc) are allotetraploid descendant species of the ancestors of the diploid species N. attenuata (Na) and N. obtusifolia (No). From cDNA, intron and promoter sequence analyses, and Southern blotting, we deduced that only the maternally derived No TPI genes were retained in the tetraploid genomes (Nq, Nc), whereas the sequences of the paternal Na ancestor were deleted. The number of TPI repeats in different Nicotiana taxa was independent of phylogenetic associations. In Na, TPI activity and mRNA transcript accumulation as well as JA levels increased dramatically above wound-induced levels when the oral secretions (OS) from Manduca sexta larvae were introduced into wounds. This OS-mediated amplification of defense signaling and downstream response was also found in the tetraploid genomes but was absent from No; in No, OS treatment suppresses TPI mRNA accumulation and activity and does not increase JA accumulation. Hence, the tetraploids retained components of Na's signaling system, but lost Na's TPI genes and used No's TPI genes to retain a functional TPI defense system, underscoring the genomic flexibility that enables complex polygenic traits to be retained in allopolyploid species"
Keywords:		"Amino Acid Sequence Animals *Biological Evolution Blotting, Southern Cloning, Molecular Larva/physiology Manduca/physiology Molecular Sequence Data *Polyploidy Sequence Analysis, DNA Species Specificity Tobacco/*genetics/parasitology/physiology Trypsin In;"
Notes:		"MedlineWu, Jianqiang Hettenhausen, Christian Baldwin, Ian T eng Research Support, Non-U.S. Gov't Germany 2006/03/15 Planta. 2006 Sep; 224(4):750-60. doi: 10.1007/s00425-006-0256-6. Epub 2006 Mar 14"