Abstract: Methods and compositions are described using tryptophan analogs, indole analogs, and mixtures thereof as agents for selecting plant cells that have been transformed with an anthranilate synthase (ASA2) gene or a fragment thereof, where the ASA2 gene encodes a feedback-insensitive form of anthranilate synthase (AS).

Abstract: A 5-methyltryptophan resistant Nicotiana anthranilate synthase genes are disclosed, in particular the ASA2 gene of Nicotiana tabacum. Constructs containing the genes are also disclosed. This genes are useful for transforming plant cells and producing transformed plants and progenies which, compared to untransformed plant cells and plants, are more resistant to tryptophan analogs and/or produce increased levels of tryptophan. The transformed seeds are also disclosed. The genes are also useful as selectable markers. The amino acid sequence of ASA2, purified ASA2, and recombinant ASA2 are also disclosed.

Abstract: A selectable marker, the ASA2 gene of Nicotiana tabacum, is provided for transforming plant cells. The ASA2 promoter sequence is also provided which is capable of directing tissue culture specific transcription of a downstream structural gene. Also disclosed are truncated forms of the ASA2 promoter which are capable of directing high level constitutive transcription of downstream structural genes. Constructs containing the above genes and promoters are also disclosed.

Abstract: An in vitro method for screening Glycine max cells for resistance to a disease caused by Phialophora gregata, brown stem rot, is disclosed. The method is useful for identifying brown stem rot resistant soybean varieties. Means for selecting mutant soybean cells for resistance to a toxin produced by P. gregata is also provided, as are cells and plants selected by this process. The invention involves culture of soybean calli in the presence of a filtrate of used fungal growth medium.

Abstract: A method is provided for the production of organogenic tissue culture and regeneration of whole plants of Glycine species, preferably Glycine max, involving the use of an organogenic culture medium comprising high cytokinin, preferably at least about 10 .mu.M BAP, and also preferably comprising at least about 6 times normal concentration of MS micronutrients. The organogenic culture medium is useful for the production of plants embodying desirable characteristics induced by somaclonal variation.