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- Moles, Angela T, et al.
(författare)
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Correlations between physical and chemical defences in plants : tradeoffs, syndromes, or just many different ways to skin a herbivorous cat?
- 2013
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Ingår i: New Phytologist. - : Wiley-Blackwell. - 0028-646X .- 1469-8137. ; 198:1, s. 252-263
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Tidskriftsartikel (refereegranskat)abstract
- Most plant species have a range of traits that deter herbivores. However, understanding of how different defences are related to one another is surprisingly weak. Many authors argue that defence traits trade off against one another, while others argue that they form coordinated defence syndromes. We collected a dataset of unprecedented taxonomic and geographic scope (261 species spanning 80 families, from 75 sites across the globe) to investigate relationships among four chemical and six physical defences. Five of the 45 pairwise correlations between defence traits were significant and three of these were tradeoffs. The relationship between species' overall chemical and physical defence levels was marginally nonsignificant (P=0.08), and remained nonsignificant after accounting for phylogeny, growth form and abundance. Neither categorical principal component analysis (PCA) nor hierarchical cluster analysis supported the idea that species displayed defence syndromes. Our results do not support arguments for tradeoffs or for coordinated defence syndromes. Rather, plants display a range of combinations of defence traits. We suggest this lack of consistent defence syndromes may be adaptive, resulting from selective pressure to deploy a different combination of defences to coexisting species.
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| 2. |
- Moles, A. T., et al.
(författare)
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Putting plant resistance traits on the map : A test of the idea that plants are better defended at lower latitudes
- 2011
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Ingår i: New Phytologist. - : Wiley. - 0028-646X .- 1469-8137. ; 191:3, s. 777-788
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Tidskriftsartikel (refereegranskat)abstract
- It has long been believed that plant species from the tropics have higher levels of traits associated with resistance to herbivores than do species from higher latitudes. A meta-analysis recently showed that the published literature does not support this theory. However, the idea has never been tested using data gathered with consistent methods from a wide range of latitudes. • We quantified the relationship between latitude and a broad range of chemical and physical traits across 301 species from 75 sites world-wide. • Six putative resistance traits, including tannins, the concentration of lipids (an indicator of oils, waxes and resins), and leaf toughness were greater in high-latitude species. Six traits, including cyanide production and the presence of spines, were unrelated to latitude. Only ash content (an indicator of inorganic substances such as calcium oxalates and phytoliths) and the properties of species with delayed greening were higher in the tropics. • Our results do not support the hypothesis that tropical plants have higher levels of resistance traits than do plants from higher latitudes. If anything, plants have higher resistance toward the poles. The greater resistance traits of high-latitude species might be explained by the greater cost of losing a given amount of leaf tissue in low-productivity environments. © 2011 New Phytologist Trust.
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| 3. |
- Ejrnaes, K, et al.
(författare)
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Characteristics of Escherichia coli causing persistence or relapse of urinary tract infections Phylogenetic groups, virulence factors and biofilm formation
- 2011
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Ingår i: VIRULENCE. - 2150-5594. ; 2:6, s. 528-537
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Tidskriftsartikel (refereegranskat)abstract
- Abstract: Recurrent urinary tract infections (RUTIs) pose a major problem but little is known about characteristics of Escherichia coli associated with RUTI. This study includes E. coli from 155 women with community-acquired lower urinary tract infections (UTIs) randomized to one of three dosing regiments of pivmecillinam and aimed to identify associations between the presence of 29 virulence factor genes (VFGs), phylogenetic groups and biofilm formation and the course of infection during follow-up visits at 8-10 and 35-49 d post-inclusion, respectively. E. coli causing persistence or relapse were more often of phylogenetic group B2 and had a significantly higher aggregate VFG score than E. coli that were not detectable at follow-up. Specifically, these E. coli causing persistence or relapse were characterized by a higher prevalence of hemolysis and 12 VFGs (sfa/focDE, papAH, agn43, chuA, fyuA, iroN, kpsM II, kpsM II K2, cnf1, hlyD, malX and usp). KpsM II K2 and agn43a(CFT073) were independently associated with persistence or relapse. No specific combination of presence/absence of VFGs could serve as a marker to predict RUTI. Stratifying for VFGs, seven days of pivmecillinam treatment reduced the prevalence of persistence or relapse of UTI compared with three days. In vitro biofilm formation was not higher among E. coli causing persistence or relapse. The presence of agn43a(CFT073) or agn43b(CFT073) was associated with biofilm forming capacity. In conclusion, our results show potential targets for prevention and treatment of persistence/relapse of UTI and potential markers for selecting treatment lengths and warrant studies of these and new VFGs.
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