Auxotrophic mutants

ABA-deficient mutants flc, not and sit

Accessions containing the genes flc, not, and sit benefit from exogenous application of abscissic acid. Weekly foliar applications of the following ABA solution should begin as soon as seedlings show signs of overwilting and/or burning of leaf margins:

  • 50 mg ABA (Aldrich # 86216-9) dissolved in 5 ml ethanol
  • 0.4 ml Triton-X
  • 4000 ml water
notabilis mutant with burned leaf margins
Shoots of the notabilis mutant (not) grown without exogenous ABA and showing burned leaf margins. [photo C.M. Rick]

GA-deficient mutants gib-1, gib-2 and gib-3

Accessions containing the genes gib-1, gib-2, and gib-3 benefit from exogenous application of gibberellic acid. The gib-1 mutation has the most pronounced phenotype (see photo) and seed will rarely germinate without supplemental GA. To germinate GA-deficient stocks, apply a 100 micromolar concentration of GA to seeds. In addition to the application of GA, cutting the tip of the seeds opposite the radicle increases germination rates.

GA-deficient gib-1 mutant in field
The GA-deficient mutant gib-1 grown in the field without exogenous GA. [photo Peter March]

Thiamine-deficient mutants tl, spa and ten

Stocks of the tl mutant require exogenous thiamine applications to survive past the cotyledon stage. The mutants ten and spa grow better when supplied with thiamine. Regular foliar applications of a 10-20 ppm solution of thiamine should begin after seedlings emerge. Once plants are established, thiamine can be easily supplied by inserting tablets of vitamin B-1 into the soil near the roots.

thiamineless mutant
Plants of the thiamine-deficient mutant tl (LA0758) with (L) and without (R) applied thiamine.


Kerr E.A. (1972) A simplified method of supplying thiamine to tomato mutants requiring it. Tomato Genetics Cooperative Report 22: 12.

Koorneef M., T.D.G. Bosma, C.J. Hanhart, J.H. van der Veen and J.A.D. Zeevaart (1990) The isolation and characterization of gibberellin-deficient mutants in tomato. Theoretical and Applied Genetics 80: 852-857.

Sharp, R.E., M.E. LeNoble, M.A. Else, E.T. Thorne, and F. Gherardi (2000) Endogenous ABA maintains shoot growth in tomato independently of effects on plant water balance: evidence for an interaction with ethylene. Journal of Experimental Botany 51: 1575-1584.