Team:KU Leuven/Project/Ecological/wetlab
From 2013.igem.org
Secret garden
Congratulations! You've found our secret garden! Follow the instructions below and win a great prize at the World jamboree!
- A video shows that two of our team members are having great fun at our favourite company. Do you know the name of the second member that appears in the video?
- For one of our models we had to do very extensive computations. To prevent our own computers from overheating and to keep the temperature in our iGEM room at a normal level, we used a supercomputer. Which centre maintains this supercomputer? (Dutch abbreviation)
- We organised a symposium with a debate, some seminars and 2 iGEM project presentations. An iGEM team came all the way from the Netherlands to present their project. What is the name of their city?
Now put all of these in this URL:https://2013.igem.org/Team:KU_Leuven/(firstname)(abbreviation)(city), (loose the brackets and put everything in lowercase) and follow the very last instruction to get your special jamboree prize!
![tree](https://static.igem.org/mediawiki/2013/a/ac/Tree.png)
![ladybugcartoon](https://static.igem.org/mediawiki/2013/6/64/Ladybugcartoon.png)
E. coligy: Plants with BanAphids - insect experiments
In order to validate the BanAphids' model, we decided to investigate the effect of the two substances, E-beta-farnesene (EBF) and Methyl Salicylate (MeS) on aphids. Once we started our project, we noticed that we were not the only ones approaching this agricultural problem from this angle. Research groups like Rothamsted are currently investigating the use of EBF to repel aphids as well but in the form of GM crops. We also found that other areas of the industry were also interested in our project such as Biobest, worldwide leader in sustainable crop protection and pcfruit whose mission is to research prospects for biological fruit growing, new crop protection methods, etc. We were invited to perform our insect experiments at Biobest and pcfruit to validate the BanAphids model. We attempted to determine the working concentrations of our two substances in pure form and to examine the preference of aphids and their predators under different conditions and environments. With the data we have collected so far, we can observe that these two substances indeed do have an effect on aphids.
![](https://static.igem.org/mediawiki/2013/9/9c/Biobest.png)
Biobest
![](https://static.igem.org/mediawiki/2013/c/c8/PcFruitLogo.png)
pcfruit
BanAphid's products
Proposed functions of methyl salicylate
When aphids feed on plants, plants will react by emitting herbivore-induced plant volatiles, and these mediate relationships between plants and insects through the attraction of natural enemies and the repulsion of herbivores (Vlot et al., 2008). Aphid feeding will specifically induce a significantly higher production of MeS than any other herbivore-induced plant volatile (Blande et al., 2010). MeS is a volatile phytohormone that is a product of the salicylic acid pathway. Since it is a volatile, MeS can induce defence systems in neighbouring plants as well as itself (Heidel and Baldwin, 2004). In addition to the activation of plant defence systems, MeS has been shown to have another function, it is a potent attractor of natural and effective aphid predators, this includes the seven-spotted ladybug (Coccinella septumpunctata) (Zhu and Park, 2005). Therefore, with the information we have gathered, we expect the BanAphids to be able to attract the aphid's natural predators and activate plant defence mechanisms in order to fend off current and future aphid infestations.
![](https://static.igem.org/mediawiki/2013/4/4d/Wingedaphid.png)
Winged aphid getting ready to migrate (Vilhjalmur Ingi Vilhjalmsson)
![](https://static.igem.org/mediawiki/2013/f/fb/Aphid_graph.png)
Changes in aphid acceptance with MeS treated plants Bars show median aphid settling + standard deviation, plant stages are categorised by the number of leaves. (Ninkovic et al., 2003)
Aphids
Aphids are small, soft-bodied insects that feed on sap from leaves, twigs, or roots. Adult aphids exist in two forms, winged or wingless. They are most common in spring and summer. Under ideal temperatures, many aphid species can complete their life cycle in less than 2 weeks, and because of their prolific reproductive capacity, enormous populations of aphids can build up in a short time. It is commonly known that when insects damage plants, these plants respond by emitting a range of volatile organic compounds (VOCs) (Blande et al., 2010). Damage caused by chewing herbivores releases a different profile of VOCs than damage by aphid feeding (piercing sucking insects) (Leitner et al., 2005). Blande et al. identified MeS as the most distinctive indicator of aphid feeding in the VOC emission profile. A significant increase in MeS VOC emission was detected from aphid infested plants as well as a significant time effect, meaning that MeS emission intensity increased with the length of the aphid infestation. The effect of aphid feeding on a plant’s MeS induction is immense, even though the feeding pressure due to aphids must exceed a threshold level before inducing volatile emissions. MeS comprises almost two-thirds of the total emission, even after 21 days of aphid feeding, compared to a negligible emission from control plants (Blande et al., 2010). MeS is an important compound of a plant’s defence mechanisms acting both as an aphid repellent (Glinwood and Pettersson, 2000) and an attractor of natural predators and parasitoids of aphids (Zhu and Park, 2005). In field trials, MeS successfully reduced initial colonisation of cereals by bird cherry-oat aphids (Rhopalosiphum padi) migrants (Pettersson et al., 1994). R. padi alternate between a winter host, bird cherry Prunus padus tree and a summer host, cereals, by means of winged aphid migrants(Pettersson et al., 1994). With this and following studies, it has been shown that the principal mode of action against aphids is repellency, which is what we want to achieve with MeS and EBF. The behavioural response of aphids to these substances is increased mobility, reduced reproductive efficiency and increased mortality of adults. An aphid’s response however, appears to be dynamic, losing their negative response to MeS after three or four days of adult life (Glinwood and Pettersson, 1999). A further study showed that application of MeS significantly reduced the mean aphid numbers in cereal crops by 25-50% (Ninkovic et al., 2003). The immigration and settling of R. padi in barley fields was delayed due to MeS application as well as a significant reduction in maximum aphid densities. Preference tests however showed that the effect of MeS on settling of R. padi on barley decreases with increasing plant age, demonstrating yet again the dynamicity of aphid behavioural responses (Ninkovic et al., 2003).