Mutator-induced mutation on 8L affects the chloroplast cytochrome b6/f complex

A mutation affecting the cytochrome b6/f complex which was isolated from among M2 progeny mutagenized with Robertson's Mutator was uncovered by TB-8Lc. The mutation, 1113-3 (a lab designation), is a nuclear lesion which results in the loss of the cytochrome b6/f complex of photosynthetic electron transport.

Mutant plants have an easily detected yellow-green phenotype and exhibit abnormal chlorophyll fluorescence and fluorescence induction kinetics. Staining of thylakoid polypeptides with 3,3',5,5'-tetramethylbenzidine (TMBZ) following separation by LDS-polyacrylamide gel electrophoresis reveals the loss of cytochromes b6 and f from the mutants. They are also significantly reduced in electron transport activity through the complex.

TB crosses were made and harvested by Dan England, for which we are grateful. We identified 6 of 90 progeny which were yellow-green, had abnormal chlorophyll fluorescence and the expected induction kinetics and also lacked cytochromes b6 and f on TMBZ stained gels.

Concurrent tests of allelism with hcf2 and hcf6 (located on 1L and 1S respectively) were reassuringly negative.

Bill Cook, Marj Hunt and Don Miles
 
 


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