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ARS Home » Midwest Area » Columbia, Missouri » Plant Genetics Research » Research » Publications at this Location » Publication #74851
Title: ORGANIZATION OF GROWTH-REGULATING GENES IN MAIZE: 1. THE FUNCTIONAL CLUSTERS OF GENES

Author
item KHAVKIN, E - INST AGRI BIOTECH MOSCOW
item Coe Jr, Edward

Submitted to: Russian Journal of Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/15/1995
Publication Date: N/A
Citation: N/A

Interpretive Summary: This study was designed to test the classical assumption that genes significant to growth and development (i.e., productivity in corn (maize, Zea mays L.) are distributed at random locations in the chromosomes. This assumption substantially defines procedures used in breeding improved corn for hybrids. In the 10 chromosomes of corn, genes that affect growth, development, and stress response are shown to be in clusters on the chromosome maps, i.e., nonrandomly distributed. Evidence for clustering was derived through summarization and analysis of locations of these classes of genes. Because significant genes are clustered, the following impacts are evident: 1) advancements are needed in methods for recombining blocks of genes and for increasing map resolution; and 2) advancements require more detailed definition of cell signaling and coordination of functions within plant cells. The value of this information is that it suggests a further need to develop focused and incisive breeding strategies for crop improvement.

Technical Abstract: In the maize (Zea mays L.) genome, the loci with phenotypic expression related to growth and development appear to associate in clusters about 10 to 30 cM long, which are unevenly distributed along the chromosomes. A typical cluster of visibly observed polymorphisms includes mutants expressing retarded stem growth, changed attitude, and disturbed growth of leaves, stems, and roots or their components, reduction and various malformations of inflorescences, and vivipary. This pattern is repeated, with considerable consistency, in different regions of the genetic map. The combined length of these clusters is about 30% of the total map length. This can be interpreted to suggest that these reiterating clusters are functional units comprising genes for sensors and transducers to translate environmental and hormonal signals to growth machinery, combined with master genes to govern the critical spatial and temporal transitions in cell growth and differentiation. The physiological advantage of close association of functionally related genes in clusters may rely on compartmentation of signal molecules, which helps cooperatively recruit the transcription factors into multicomponent regulatory modules of high specificity.