1 D224P6 : MOLECULAR TECHNIQUES IN BIOSCIENCES

1 D224P6 : MOLECULAR TECHNIQUES IN BIOSCIENCES



1 D224P6 : MOLECULAR TECHNIQUES IN BIOSCIENCES

Research Summary

Organisms need to adapt themselves to changes in fluctuating environmental conditions. The plants, since they are not able to scape from adverse environmental conditions, have torely entirely on their developmental plasticity to survive (Krouk et al., 2011). The seadaptations include the responses to temperature fluctuations, water and nutrients imbalance, UV radiation, pathogens, and insects, among other biotic and abiotic stresses. Plant growth regulators (phytohormones), compounds derived from plant biosynthetic pathways, mediate these responses by acting either at the site of synthesis or following their transport, elsewhere in the plant. Collectively, plant hormones regulate every aspect of plant growth, development and the responses of plants to biotic and abiotic stresses (Peleg & Blumwald, 2011).

Method Review

Classical phytohormones are abscisic acid (ABA), ethylene, cytokinin (CK), auxin, gibberellin, jasmonate, as well as brassinosteroids, salicylic acid, nitric oxide, and strigolactone, and it is likely that additional growth regulators are yet to be discovered (Santner & Estelle, 2009). ABA synthesis is one of the fastest responses of plants to water stress, triggering ABA-inducible gene expression and causing stomatal closure, thereby reducing water loss via transpiration and eventually restricting cellular growth (Wilkinson & Davies, 2010; Yamaguchi-Shinozaki & Shinozaki, 2006). Many ABA-mediated

physiological processes induced by water deficit, including closure of the stomata and acceleration of leaf senescence, are counteracted by CKs which increase stomatal aperture and/or delay ABA-induced stomatal closure. It has been suggested that in longer-term responses to stress, hormones such as ABA and CK may function to regulate the production, metabolism and distribution of metabolites essential for stress survival and recovery (Pospi´s?ilova´ & Dodd, 2005; Stoll et al., 2000).

Strains of Agrobacterium tumefaciens carrying two different plasmids: (1) The A. tumefaciens strain EHA101 harboring a binary plasmid, pCAMBIA 1301 (Fig. 1a). The plasmid contains the $-glucuronidase reporter gene (gus) (Jefferson et al., 1986) from Escherichia coli with an intron, driven by cauliflower mosaic virus (CaMV) promoter and nos poly-A terminator sequences together with the selectable marker gene hygromycin phosphotransferase gene (hpt) under the control of CaMV 35S promoter and CaMV 35S poly-A terminator. (2) Agrobacterium tumefaciens strain LBA 4404 harboring a binary plasmid, pCambar containing gus, hptand bar genes (Fig. 1b). The bar gene was originally cloned from the bacterium Streptomycin hygroccopius. It encodes phosphinothricin acetyltransferase (PPT)

(Thompson et al., 1987) that detoxifies phosphinothricin or glufosinate, the active ingredient of the herbicides Liberty and Basta (De Block et al., 1987). The gus reporter gene is driven by CaMV 35S promoter and nos poly-A terminator, hpt gene is driven by CaMV 35S promoter and CaMV 35S poly-A terminator and the bar gene is driven by CaMV 35S promoter and nos poly-A terminator.

We focus on understanding the complexity of biological systems at a molecular level. Working at the interface of Biology, Chemistry and Biophysics, we bring new approaches to fundamental biological questions as well as the design of drugs and biomaterials. The work encompasses Physical Biochemistry together with Chemical, ...