Maize protoplasts

Imbrie-Milligan, C.W. Hodges, T.K. (1986). Microcallus formation from maize protoplasts prepared from embryogenic callus. Planta, 168, 395-401. 

Fig. 3. The ARE sequence and mutated versions. The regions altered in the mutated AREs are indicated by blocks. The mutated AREs were multimerised and binding activity assayed by gel retardation. Each multimerised ARE was linked to a GUS reporter gene, electroporated into maize protoplasts and assayed for anaerobically induced expression of GUS.

Howard, E.A., Walker, J.C., Dennis, E.S. Peacock, W.J. (1987). Regulated expression of an alcohol dehydrogenase-1 chimeric gene introduced into maize protoplasts. Planta 170, 535-40. 

A more significant body of literature focuses on the use of protoplasts in understanding processes related to stress tolerance. The role of Ca in salt toleranee has been evaluated using maize root protoplasts. Exposure of the plasmalemma directly to external media revealed a non-specific replacement of Ca by salt. Sodium was found to replace Ca though this could be reversed by adding more Ca (Lynch, Cramer Lauchli, 1987). This approach assists in understanding the role of specific ion interaction in enhancing salt tolerance and is potentially applicable to studies on the molecular basis for ion specificity of plant membranes. 

Fig. 10.2. FSPIM analysis of the interaction between maize transcriptional coactivators—GCN5 and ADA2—fused to CFP and YFP. GCN5 is a histone acetyltransferase that, in conjunction with adaptor protein ADA2, modulates transcription in diverse eukaryotes by affecting the acetylation status of the core histones in nucleosomes [63]. CFP- and YFP-tagged proteins, expressed in protoplasts, were excited by the 458 nm and the 514 nm laser lines sequentially. CFP fluorescence was selectively detected by an FIFT 458 dichroic mirror and BP 470-500 band pass emission filter while YFP fluorescence was selectively detected by using an HFT 514 dichroic mirror and...

Omirulleh, S Abraham, M., Golovkin, M., Stefanov, 1., Karabaev, M.K., Mustardy, L., Morocz, S., and Dudits, D. (1993). Activity of a chimeric promoter with the doubled CaMV 35S enhancer element in protoplast-derived cells and transgenic plants in maize. Plant Mol. Biol. 21(3) 415-428. 

Urao et al. (1994) [87] cloned two closely related Ca dependent protein kinases from Arabidopsis and showed that they are ABA inducible. Overexpression of these kinases in protoplasts isolated from maize leaves leads to induction of an ABA responsive promoter [75]. Coexpression of ABIl inhibits the induction. It is difficult to make this fit with the role of ABIl as a mediator of ABA induced gene expression. The mechanism of action of ABIl and the dominant effects of the abil mutation have not yet been clarified. It is possible that overexpression of ABIl has the same effect as the abil mutant protein. 

Chang, T.Y., Senn, A., Pilet, P.E., 1983. Effect of abscisic acid on maize (Zea maize vs. LG-11) root protoplasts. Zeitschrift fiir Pflanzenphysiologie 110, 127-134. 

Thus, molecular tools (antibodies and cDNA probes) to investigate auxin action are now available. We are now in the process of utilizing the polyclonal and monoclonal antibodies for immunopurification and also to probe receptor structure and function in maize and in other species. For example, preliminary results from Prof. J. Guern s laboratory (by H. Barbier-Brygoo, Gif) show that the antiserum blocks auxin-induced hyperpolarization of tobacco protoplasts. We are also seeking to use the antibodies to examine receptor features in auxin response mutants of several species and to explore signal transduction pathways. 

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