The evolution of herbivore-regulated secondary metabolism during polyploid speciation in native Nicotiana

• Applicant: Dr. Nan Qu
• Subject Area: Plant Biochemistry and Biophysics
• Term: from 2003 to 2007
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 5411676

The transcriptional regulation of secondary metabolism plays a central role in "fitting" a plant to a particular environment, and polyploid speciations are frequently associated with adap tive radiations, with the polyploid taxa exhibiting greater ability to survive under unfavorable conditions. However, next to nothing is known about the regulation of gene expression in the newly formed polyploid taxa, and we propose to study how transcriptionally regulated ecological adaptations are conserved or altered d uring polyploid speciation events. Specifically, we will examine how the changes in secondary metabolism and transcription that are elicited in the diploid ancestor, N. attenuata when attacked by a specialist herbivore, Manduca sexta, are maintained or modified in the two allotetraploid species, N. bigelovii and N. clevelandii. All three plant species occur allopatrically in North America and are attacked by similar herbivore communities. Cis-elements coordinating the changes in secondary metabolism after herbivore attack in N. attenuata will be identified by means of deleted promoter-GUS fusion constructs and used to isolate targeted trans-activating elements. These cis-elements and trans-activating factors will be studied in the allotetraploid taxa to understand the mechanisms which determine whether ecological adaptations are conserved or altered during this ubiquitous form of speciation.

• DFG Programme: Priority Programmes
• Subproject of: SPP 1152: Evolution of Metabolic Diversity
• Participating Person: Professor Dr. Ian Thomas Baldwin