Plastic defence expression in plants
- 533 Downloads
Phenotypic plasticity is the ability of an organism to express different phenotypes in response to changing environments and becomes particularly obvious when plants alter their transcriptome after enemy attack. The resulting alterations affect the metabolic, chemical and morphological phenotype and cause resistance or tolerance phenomena, which allow plants to main high fitness in the presence of enemies. Volatiles released from damaged plants can be received by their neighbours or undamaged parts of the same plant to mount an adequate level of resistance and thereby add a further level of phenotypic plasticity. The induced defence responses also include attraction of the third trophic level and, thus, dramatic changes of the ‘extended phenotype’ of the plant, that is, its surrounding fauna. The underlying interactions are, at least partly, under the control of the plant and, thus, subject to co-evolutionary processes. Fitness costs are a common explanation for the evolution of inducible resistance expression. However, variability in the resistance phenotype can per se be beneficial, because it makes counter-adaptations by the plants’ enemies more difficult. In the case of indirect defences, which are mediated by plant-carnivore mutualisms, signal reliability and reciprocal responses among phenotypically plastic partners appear necessary prerequisites for their evolutionary stabilisation. The expression of resistance and tolerance is induced by enemy attack but is also under control by abiotic factors, such as resource supply, and by biotic parameters, such as current and anticipated competition, efficiency of the expressed resistance and ontogenetic stage. All these levels of plasticity help plants to survive as sessile organisms in a rapidly changing environment and in the presence of mobile enemies.
KeywordsCompensation Induced resistance Indirect defence Phenotypic plasticity Priming Tolerance
The expression levels of constitutive resistance are not affected by encounters with plant enemies. They, can, however, be subject to phenotypic plasticity with respect to other factors such as, for example, abiotic conditions.
All strategies that increase plant fitness in the presence of enemies. The term as used here comprises both resistance and tolerance.
Direct resistance traits are those that directly interact with the plant enemy in order to reduce feeding activity or infection level.
Indirect defence traits do not directly interact with the plant enemy but rather enhance the presence of ‘enemies of the enemy of the plant’.
Induced resistance traits change their expression level in response to an encounter with an enemy of the plant.
The capacity of a certain genotype to express different phenotypes in response to changing environmental conditions.
Plant traits that reduce the degree or probability at which enemies of the plants exert damage.
Tolerance traits minimize the fitness loss that is caused by a certain level of damage.
- Beach RM, Todd JW, Baker SH (1985) Nectaried and nectariless cotton cultivars as nectar sources for the adult soybean looper. J Entomol Sci 20:233–236Google Scholar
- Brown DG (1988) The cost of plant defense: an experimental analysis with inducible proteinase inhibitors in tomato. Oecologia 76:467–470Google Scholar
- Dicke M (1999) Evolution of induced indirect defense of plants. In: Tollrian R, Harvell CD (eds) The ecology and evolution of inducible defences. Princeton University Press, Princeton, pp 62–88Google Scholar
- Fornoni J, Núñez-Farfán J (2003) Evolutionary ecology of tolerance to herbivory: advances and perspectives. Comm Theoret Biol 8:643–663Google Scholar
- Fornoni J, Valverde PL, Nunez-Farfan J (2003) Quantitative genetics of plant tolerance and resistance against natural enemies of two natural populations of Datura stramonium. Evol Ecol Res 5:1049–1065Google Scholar
- Gardner SN, Agrawal AA (2002) Induced plant defence and the evolution of counter-defences in herbivores. Evol Ecol Res 4:1131–1151Google Scholar
- González-Teuber M, Gianoli E (2008) Damage and shade enhance climbing and promote associational resistance in a climbing plant. J Ecol 96:122–126Google Scholar
- Heil M, Karban R (2010) Explaining evolution of plant communication by airborne signals. publ online, Trends Ecol EvolGoogle Scholar
- Heil M, Walters D (2009) Ecological consequences of plant defence signalling. In: Van Loon LC (ed) Plant Innate Immunity. Elsevier, London, pp 667–716Google Scholar
- Hermsmeier D, Schittko U, Baldwin IT (2001) Molecular interactions between the specialist herbivore Manduca sexta (Lepidoptera, Sphingidae) and its natural host Nicotiana attenuata. I. Large-scale changes in the accumulation of growth- and defense-related plant mRNAs. Plant Physiol 125:683–700PubMedCrossRefGoogle Scholar
- Hölldobler B, Wilson EO (1990) The ants. Springer, BerlinGoogle Scholar
- Izaguirre MM, Mazza CA, Biondini M, Baldwin IT, Ballaré CL (2006) Remote sensing of future competitors: impacts on plant defences. Proceedings of The National Academy Of Sciences of the United States Of America 103: 7170–7174Google Scholar
- Karban R, Baldwin IT (1997) Induced responses to herbivory. University of Chicago Press, Chicago and LondonGoogle Scholar
- Miller B, Madilao LL, Ralph S, Bohlmann J (2005) Insect-induced conifer defence. White pine weevil and methyl jasmonate induce traumatic resinosis, de novo formed volatile emissions, and accumulation of terpenoid synthase and putative octadecanoid pathway transcripts in Sitka spruce. Plant Physiol 137:369–382PubMedCrossRefGoogle Scholar
- Núñez-Farfán J, Fornoni J, Valverde PL (2007) The evolution of resistance and tolerance to herbivores. Annual review of ecology evolution and systematics 38: 541–566Google Scholar
- Stapel JO, Cortesero AM, DeMoraes CM, Tumlinson JH, Lewis WJ (1997) Extrafloral nectar, honeydew, and sucrose effects on searching behavior and efficiency of Microplitis croceipes (Hymenoptera: Braconidae) in cotton. Environ Entomol 26:617–623Google Scholar