| Title: | Flower-specific jasmonate signaling regulates constitutive floral defenses in wild tobacco |
| Author(s): | Li R; Wang M; Wang Y; Schuman MC; Weinhold A; Schafer M; Jimenez-Aleman GH; Barthel A; Baldwin IT; |
| Address: | "Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany. Department of Bioorganic Chemistry, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany. Department of Entomology, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany. Department of Molecular Ecology, Max Planck Institute for Chemical Ecology, D-07745 Jena, Germany; Baldwin@ice.mpg.de" |
| ISSN/ISBN: | 1091-6490 (Electronic) 0027-8424 (Print) 0027-8424 (Linking) |
| Abstract: | "Optimal defense (OD) theory predicts that within a plant, tissues are defended in proportion to their fitness value and risk of predation. The fitness value of leaves varies greatly and leaves are protected by jasmonate (JA)-inducible defenses. Flowers are vehicles of Darwinian fitness in flowering plants and are attacked by herbivores and pathogens, but how they are defended is rarely investigated. We used Nicotiana attenuata, an ecological model plant with well-characterized herbivore interactions to characterize defense responses in flowers. Early floral stages constitutively accumulate greater amounts of two well-characterized defensive compounds, the volatile (E)-alpha-bergamotene and trypsin proteinase inhibitors (TPIs), which are also found in herbivore-induced leaves. Plants rendered deficient in JA biosynthesis or perception by RNA interference had significantly attenuated floral accumulations of defensive compounds known to be regulated by JA in leaves. By RNA-seq, we found a JAZ gene, NaJAZi, specifically expressed in early-stage floral tissues. Gene silencing revealed that NaJAZi functions as a flower-specific jasmonate repressor that regulates JAs, (E)-alpha-bergamotene, TPIs, and a defensin. Flowers silenced in NaJAZi are more resistant to tobacco budworm attack, a florivore. When the defensin was ectopically expressed in leaves, performance of Manduca sexta larvae, a folivore, decreased. NaJAZi physically interacts with a newly identified NINJA-like protein, but not the canonical NINJA. This NINJA-like recruits the corepressor TOPLESS that contributes to the suppressive function of NaJAZi on floral defenses. This study uncovers the defensive function of JA signaling in flowers, which includes components that tailor JA signaling to provide flower-specific defense" |
| Keywords: | "Animals Cyclopentanes/*immunology Feeding Behavior Flowers/*immunology/parasitology Gene Expression Regulation, Plant Manduca/physiology Oxylipins/*immunology Plant Proteins/genetics/*immunology Tobacco/genetics/*immunology/parasitology Heliothis virescen;" |
| Notes: | "MedlineLi, Ran Wang, Ming Wang, Yang Schuman, Meredith C Weinhold, Arne Schafer, Martin Jimenez-Aleman, Guillermo H Barthel, Andrea Baldwin, Ian T eng 293926/ERC_/European Research Council/International Research Support, Non-U.S. Gov't 2017/08/09 Proc Natl Acad Sci U S A. 2017 Aug 22; 114(34):E7205-E7214. doi: 10.1073/pnas.1703463114. Epub 2017 Aug 7" |
