Scientists are interested in understanding genetic control of grass inflorescence architecture because seeds of cereal grasses (e.g. rice, wheat, maize) provide most of the world's food. Grass seeds are borne on axillary branches, whose branching patterns dictate most of the variation in form seen in the grasses. Maize produces two types of inflorescence; the tassel (male pollen-bearing flowers) and the ear (female flowers and site of seed or kernel development). The tassel forms from the shoot apical meristem after the production of a defined number of leaves, whereas ears form at the tips of compact axillary branches. Normal maize ears are unbranched, and tassels have long branches only at their base.
Many different genes control the architecture as well as the nutrient content in cereal grasses. The ramosa2 (ra2) mutant of maize has increased branching of inflorescences relative to wild type plants, with short branches replaced by long, indeterminate ones, suggesting that the ra2 gene plays an important role in controlling inflorescence architecture. A recent publication in The Plant Cell (Bortiri et al.) reports that ra2 encodes a putative transcription factor, or protein that controls the expression of other genes. Scientists involved in the study were Esteban Bortiri, George Chuck, and Sarah Hake of the USDA Plant Gene Expression Center and University of California at Berkeley and colleagues Erik Vollbrecht of Iowa State University, Torbert Rocheford of the University of Illinois, and Rob Martienssen of Cold Spring Harbor Laboratory in New York.
The group found that the ra2 gene is transiently expressed early in development of the maize inflorescence. Analysis of gene expression in a number of different mutant backgrounds placed ra2 function upstream of other genes that regulate branch formation. The early expression of ra2 suggests that it functions in regulating the patterning of stem cells in axillary meristems.
Said Dr. Hake, "we Page: 1 2 Related biology news :1
Contact: Nancy Eckardt
American Society of Plant Biologists
. Clones on task serve greater good, evolutionary study shows2
. New textbook illuminates the close links between evolutionary and molecular biology3
. Coelacanth fossil sheds light on fin-to-limb evolution4
. Genomics study provides insight into the evolution of unique human traits5
. New proteomics research promises to revolutionize biomedical discovery6
. Species detectives track unseen evolution7
. Study identifies energy efficiency as reason for evolution of upright walking8
. Clues to future evolution of HIV come from African green monkeys9
. Tumor painting revolutionizes fight against cancer10
. Revolutionary global environment fund announces $50M expansion11
. A first-principles model of early evolution