10: Larrea Tridentata (Creosote) Project Background

http://www.sci.sdsu.edu/plants/sdpls/plants/Larrea_tridentata.html

Leaf Microbiome of Larrea tridentata Grown in Urban Phoenix Versus Grown in Rural Phoenix

Project Background
Research has shown rising levels of CO2 can alter the chemical composition of leaves in Larrea tridentata. Additionally, the nutrients in the soil can be altered (Wang 2011). Research has also indicated that environmental conditions and changes can influence adaptive traits of plant function over time (Kimball et. al 2012). It is imperative to learn more about the differences in the leaf microbiome of Larrea tridentata in urban and rural areas to gain understanding of how increasing urbanization can impact microbiome development and sustainability over time.
It is imperative to expand on current research of the Larrea tridentata leaves due to continuous changes in environmental conditions and the need to further understand adaptive traits of the leaf microbiome. In the study, "Urbanization alters spatiotemporal patterns of ecosystem primary production: A case study of the Phoenix metropolitan region, USA," research showed that urbanization affects the function of an ecosystem and its surrounding environments. The study also revealed that urbanization affects the net primary production of chemical energy (Buyantuyev and Wu 2009). Additionally, the study "Temporal patterns in near-surface CO2 concentrations over contrasting vegetation types in the Phoenix metropolitan area" addresses the need to study surface levels of CO2 in urban areas and its effect on plant life (Day, et al 2002).
Furthermore, some research suggests that Larrea tridentata possesses antibacterial properties in the aerial parts of the plant which can combat the increase in bacterial infections that are drug-resistant. Currently, Larrea tridentata has antibacterial properties in its leaves and understanding differences in leaf microbiomes in urban and rural areas may provide insight on antibacterial agents and their property types in different environments (urban and rural). In the recent study, "Antibacterial activity of crude methanolic extract and fractions obtained from Larrea tridentata leaves," researchers found that phytochemicals from L. tridentata leaves may aid in the development of natural antibacterial treatment (Martins 2013). The study also indicated the need to further research the hypothesis. By testing the differences in the leaf microbiome of the Larrea tridentata in urban and rural environments, it can aid in a future understanding of how urban and rural environment affects antibacterial properties of the Larrea tridentata aerial parts.

Key Terms
Aerial parts- parts of a plant that are exposed to air (i.e. leafs, stems, roots).
Net primary production- amount of chemical energy created by produces over a period of time.

Research question
Is there a difference in the leaf microbiome of the Larrea tridentata species in the Phoenix urban area and surrounding desert rural area?

Hypothesis
Hypothesis 1: The leaf microbiome of Larrea tridentata found in the urban Phoenix area is detectably different than the leaf microbiome of Larrea tridentata found in the Phoenix rural areas.
Hypothesis 2: As a result of urban area heat islands and a greater concentration of CO2 emitting vehicles, it is hypothesized that elevated CO2 and pollution will result in different microbial communities of Larrea tridentata growing in urban areas.

References:

A. Buyantuyev and J. Wu. "Urbanization alters spatiotemporal patterns of ecosystem primary production: A case study of the Phoenix metropolitan region, USA." Journal of Arid Environments, vol. 73, 2009, p. 512-520. Retrieved from https://ac.els-cdn.com/S0140196308003649/1-s2.0-S0140196308003649-main.pdf?_tid=98c8d5e0-c052-11e7-97a5-00000aab0f01&acdnat=1509684844_197eb558cc325b63cd9a6d7f80089f02

Kimball, Sarah, et al. "Fitness and physiology in a variable environment." Oecologia, vol. 169, no. 2, 2012, p. 319+. Academic OneFile,  go.galegroup.com/ps/i.do?p=AONE&sw=w&u=mcc_main&v=2.1&id=GALE%7CA356445949&it=r&asid=76cf9b7c721d99e2e39e481da1419f8d. Accessed 20 Oct. 2017.  

K.L. Neil et al. / Journal of Arid Environments 74 (2010) 440–444. https://ac.els-cdn.com/S0140196309003231/1-s2.0-S0140196309003231-main.pdf?_tid=ec4d747e-b54d-11e7-80e7-00000aab0f6c&acdnat=1508473374_2658d691676b7ce943e2833f5216b961.

Maki Jitsuno and Yoshihiro Mimaki. "Triterpene glycosides from the aerial parts of Larrea tridentata." Phytochemistry, vol. 71 2010, p. 2157–2167. Retrieved from https://ac.els-cdn.com/S0031942210003687/1-s2.0-S0031942210003687-main.pdf?_tid=82d1fcb8-c060-11e7-96af-00000aacb361&acdnat=1509690820_e82d8b4df86e7520365baba41e5ebc45

Martins,Silvia et al. "Antibacterial activity of crude methanolic extract and fractions obtained from Larrea tridentata leaves." Industrial Crops and Products, vol. 41, 2013, Pages 306-311. Retrieved from https://doi.org/10.1016/j.indcrop.2012.04.037.

Schultz, J. C., & Floyd, T. (1999, February). Desert Survivor. Natural History, 108(1), 24. Retrieved from http://link.galegroup.com.libproxy.maricopa.edu/apps/doc/A53682802/WHIC?u=mcc_main&xid=8b7d7592.

Shen, W., Wu, J., Grimm, N.B. et al. Ecosystems (2008) 11: 138. https://doi.org/10.1007/s10021-007-9085-0.

Thomas A Day, et al. "Temporal patterns in near-surface CO2 concentrations over contrasting vegetation types in the Phoenix metropolitan area." Agricultural and Forest Meteorology, vol 110, Issue 3, 2002, p. 229-245. Retrieved from http://www.sciencedirect.com.libproxy.maricopa.edu/science/article/pii/S016819230100288X#aep-section-id24

Wang, D. (2011). A meta-analysis of plant physiological and growth responses to temperature and elevated CO2. Oecologia, 169(1), 1-13. Retrieved October 19, 2017, from http://hh2wl8hm4u.search.serialssolutions.com/?ctx_ver=Z39.88-2004&ctx_enc=info%3Aofi%2Fenc%3AUTF-8&rfr_id=info%3Asid%2Fsummon.serialssolutions.com&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=A meta-analysis of plant physiological and growth responses to temperature and elevated CO2&rft.jtitle=Oecologia&rft.au=Wang%2C Dan&rft.au=Heckathorn%2C Scott A&rft.au=Wang%2C Xianzhong&rft.au=Philpott%2C Stacy M&rft.date=2012-05-01&rft.pub=Springer-Verlag&rft.issn=0029-8549&rft.eissn=1432-1939&rft.volume=169&rft.issue=1&rft.spage=1&rft.epage=13&rft_id=info:doi/10.1007%2Fs00442-011-2172-0&rft.externalDBID=n%2Fa&rft.externalDocID=2012_442_169_1_2172mdict=en-US.

Weijun Shen, et al. "Effects of Urbanization-Induced Environmental Changes on Ecosystem Functioning in the Phoenix Metropolitan Region, USA." Ecosystems (2008) vol. 11, 2008, p. 138–155. Retrieved from http://leml.la.asu.edu/jingle/Wu-Publications-PDFs/2008/Shen_etal-2008-Ecosystems.pdf