Designing an appropriate selection procedure is important for successfully identifying mutants
|Figure 1. A successful selection using media supplemented with FuDR (5-flurodeoxy uridine). There are about 12,000 spore on this dish and all except one are severly inhibited or killed by this concentration of FuDR. The single individual to the right of center exhibits tolerance to FuDR and has nearly normal growth and development.|
The identification of an appropriate selection condition typically requires careful dose response curves to determine the correct concentration of a toxin (for example, selections using herbicides, FuDR, etc.) that results in lethality or sufficient and distinctive inhibition of gametophyte growth or development. Several factors may need to be considered when choosing the appropriate selection regime, for example:
- The nature of the toxic response, e.g. whether abrupt or gradual.
- The pattern of gametophytic growth and development over time, e.g. whether gametophytes exhibit differential response dependent upon age.
- Identification of phenotypes other than growth that may identify mutants.
- Also for identification of putative morphological mutants (for example clumped chloroplast or callus-like growth habit) careful observation of gametophytes at a sufficiently young stage is important.
The standard selection procedure is outlined in this illustration.(Figure not yet available!)
A number of confirmed and putative mutants have been obtained using both X-ray and EMS mutagenesis. Protocols for X-ray or EMS mutagenesis are given in the C-Fern Web Manual.
|Mutant Selections of Ceratopteris and References|
|Selection Agent / Criteria||Strain / Mutant Codes||Reference|
|paraquat||HaPQn, pq2, pq45, pqa||
Hickok and Schwarz 1986a
|acifluorfen||HaBn / blt1||Hickok et al. 1987
|glyphosate||HaGn / glt1, glt2||Tai Chun and Hickok 1992|
|NaCl||HaNn / stl1, stl2||Hickok et al. 1987
Warne and Hickok 1987
Hickok et al. 1991
Vogelien et al. 1993
Warne et al. 1995
|azetidine-2-carboxylate||HaAZn||Hickok et al. 1987|
|5-flurodeoxy uridine||HaFn||Hickok et al. 1987|
|2-aminoethyl-L-cysteine||HaCYn||Hickok et al. 1987|
|Al2(SO4)3 at pH 4.4||HaAT37,29||Wright et al. 1990|
|antheridiogen (ACe)||HaCn / her#||
Warne et al. 1988
|abscisic acid||HaAn/ abr48, abr104||Hickok 1985a
|germination: darkness||HaDn / dkg1||Scott and Hickok 1991
Cooke et al. 1987
Cooke et al. 1993
|germination: altered red / blue responses||GERM1,2,3,4||
Cooke et al. 1995
|irregular meristem||HaTUBE1||Hickok et al. 1995|
|clumped chloroplasts||HaCPn /cp1||Vaughn et al. 1990|
|self sterility: 230X (C.thalictroides)
spermatozoid / flagella development
|Duckett et al. 1979|
(1) All listed selections, with the exception of 230X, were derived from the Hn-n strain. Strain designations ending with 'n' indicate that a number of independent selections are available, all of which have not been fully characterized genetically.
Complete information on references can be found in the Bibliography