ANTIBIOTICS-MUTAGENESIS-TESTS WITH PEAS

50 PNL Volume 17 1985 RESEARCH REPORTS

Loennig, W. E. Institute of Genetics

University of Bonn, Federal Republic of Germany

As described previously (3), streptomycin blocks chlorophyll-syn-

thesis in pea. A similar effect was found in pea seedlings when the

seeds were treated with chloramphenicol, but treatment with the antibio-

tics nitrofurazon and neomycinsulphate produced no such effect.

With respect to the streptomycin treatment, 87 families (altogether

1424 plants) of the prospective M₂ were investigated. No chlorophyll

mutants were detected among these plants. Two out of 87 families

yielded no plants at all. The mother plant of one of these two had pro-

duced only six seeds, all of which were smaller than those of DGV and

were of greenish color (instead of the normal yellow of DGV); none

germinated. For the second case no special features were noticed. A

weak mutagenicity of streptomycin would be in agreement with the

findings of Manna and Karmakar (2), but in disagreement with other

authors (see review by Suter and Jaeger [4]). The present results seem

still too scanty to decide the question, but if streptomycin is a muta-

genic agent it does not seem to be very potent. Normally the production

of different chlorophyll mutations is the first indication of a potent

mutagen in plants.

Chloramphenicol proved to be mutagenic in several bacterial tests,

but non-mutagenic in others (see [4]). As a pilot test, 200 seeds were

treated with chloramphenicol (100 seeds in 0.25% and 100 in 0.50%

chloramphenicol solution for 14 hours). Only six seeds germinated of

the group treated with the 0.5% solution and 19 of the other; two from

the latter group showed white spots in the lower leaves and lower parts

of the stems in the M1. The resulting 25 M2 families consisted of 653

plants. One of these M₂ families (with 40 plants in all [M1 treated

with 0.25% chloramphenicol-solution]) showed a mutant with relatively

large white sectors in the leaves in the upper part of the plant.

Inasmuch as our mutant collection contains no mutants resembling this

phenotype and inasmuch as no 3:1 segregation took place in the M₂, a

cross fertilization can be excluded. The M3 corroborated the conclu-

sion.

Most of the descendents of the mutant plant showed the same fea-

tures as the mother plant. Moreover, several families were descended

from the family in which the new mutant first appeared. The mother

plants had not shown the mutant character, but in some M3 families the

new mutant segregated, demonstrating that the mutation event had actual-

ly taken place in the M1 plant. I want to provisionally suggest the

symbol 1ws (large white spots) for this mutant.

So the pilot test with this small sample of only 25 families has

already produced at. least one mutant (another possible mutant affecting

internode length has not yet been proved). To verify the mutagenic

potential of chloramphenicol and its mutation spectrum in pea, a large

scale study is needed. As there have been several reports that chloram-

phenicol is also very dangerous in man (1), mutation tests with higher

plants may corroborate the bacterial test results concerning the "posi-

tive" mutagenic potential of chloramphenicol.

1. Langbein, et. al. (eds.). 1983. 'Bittere Pillen', pp. 368-

369. Kiepenheuer & Witsch, Cologne.

2. Manna, G. K., and M. Karmaker. 1979. The Nucleus 22:96-103,

3. Loennig, W.-E. PNL 15:36-37.

4. Suter, W. and I. Jaeger. 1982. Mutation Res. 97:1-18.



	50 PNL Volume 17 1985 RESEARCH REPORTS

	ANTIBIOTICS-MUTAGENESIS-TESTS WITH PEAS Loennig, W. E. Institute of Genetics University of Bonn, Federal Republic of Germany As described previously (3), streptomycin blocks chlorophyll-syn- thesis in pea. A similar effect was found in pea seedlings when the seeds were treated with chloramphenicol, but treatment with the antibio- tics nitrofurazon and neomycinsulphate produced no such effect. With respect to the streptomycin treatment, 87 families (altogether 1424 plants) of the prospective M₂ were investigated. No chlorophyll mutants were detected among these plants. Two out of 87 families yielded no plants at all. The mother plant of one of these two had pro- duced only six seeds, all of which were smaller than those of DGV and were of greenish color (instead of the normal yellow of DGV); none germinated. For the second case no special features were noticed. A weak mutagenicity of streptomycin would be in agreement with the findings of Manna and Karmakar (2), but in disagreement with other authors (see review by Suter and Jaeger [4]). The present results seem still too scanty to decide the question, but if streptomycin is a muta- genic agent it does not seem to be very potent. Normally the production of different chlorophyll mutations is the first indication of a potent mutagen in plants. Chloramphenicol proved to be mutagenic in several bacterial tests, but non-mutagenic in others (see [4]). As a pilot test, 200 seeds were treated with chloramphenicol (100 seeds in 0.25% and 100 in 0.50% chloramphenicol solution for 14 hours). Only six seeds germinated of the group treated with the 0.5% solution and 19 of the other; two from the latter group showed white spots in the lower leaves and lower parts of the stems in the M1. The resulting 25 M2 families consisted of 653 plants. One of these M₂ families (with 40 plants in all [M1 treated with 0.25% chloramphenicol-solution]) showed a mutant with relatively large white sectors in the leaves in the upper part of the plant. Inasmuch as our mutant collection contains no mutants resembling this phenotype and inasmuch as no 3:1 segregation took place in the M₂, a cross fertilization can be excluded. The M3 corroborated the conclu- sion. Most of the descendents of the mutant plant showed the same fea- tures as the mother plant. Moreover, several families were descended from the family in which the new mutant first appeared. The mother plants had not shown the mutant character, but in some M3 families the new mutant segregated, demonstrating that the mutation event had actual- ly taken place in the M1 plant. I want to provisionally suggest the symbol 1ws (large white spots) for this mutant. So the pilot test with this small sample of only 25 families has already produced at. least one mutant (another possible mutant affecting internode length has not yet been proved). To verify the mutagenic potential of chloramphenicol and its mutation spectrum in pea, a large scale study is needed. As there have been several reports that chloram- phenicol is also very dangerous in man (1), mutation tests with higher plants may corroborate the bacterial test results concerning the "posi- tive" mutagenic potential of chloramphenicol.

	1. Langbein, et. al. (eds.). 1983. 'Bittere Pillen', pp. 368- 369. Kiepenheuer & Witsch, Cologne. 2. Manna, G. K., and M. Karmaker. 1979. The Nucleus 22:96-103, 3. Loennig, W.-E. PNL 15:36-37. 4. Suter, W. and I. Jaeger. 1982. Mutation Res. 97:1-18.



	PNL Volume 17 1985	RESEARCH REPORTS 51



	Fig. 1. M3: Descendants of chlorophyll mutant which appeared after treatment with chloramphenicol.