Unstable genes affecting chloroplast development in soybean

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Y18 is a nuclear gene of soybean Glycine max necessary for normal chloroplast development. An unstable allele Y18‐m of the Y18 gene has been previously characterized genetically [Peterson and Weber: Theor Appl Genet 39:156‐162, 1969.] Plants homozygous for the unstable allele produce leaves that exhibit a variegated pattern of green and yellow leaf sectors, indicating somatic mutability events. Germinal instability is detected by the recovery of either pure breeding dominant green (rare) or pure breeding recessive yellow (frequent) plants from the mutable stock. In contrast to most unstable genes identified in other plant systems, the Y18‐m mutation is from the dominant green state to the recessive yellow state, producing a pattern of “reverse variegation.” Current work has focused on further characterization of this mutation at the whole plant level as well as at the biochemical level. These results include observations on the cell‐ and tissue‐type specificity of the mutation, stability of the recessive yellow mutation, and a biochemical analysis of mutant and normal thylakoid membranes to identify the specific polypeptides affected by the y18 mutation. Several polypeptides of the thylakoid membranes are missing, and many, including the major light harvesting complex (LHCP) polypeptides, are reduced. Messenger RNAs for LHCPII were also reduced to a greater extent than other leaf transcripts in the yellow sectors of variegated plants. A comparison of Y18‐m to other soybean mutable genes and transposable element insertions is made. Copyright © 1989 Wiley‐Liss, Inc.

Publication Title

Developmental Genetics