ARS | Publication request: SEXUAL TRANSFER OF B-CHROMOSOMES FROM MAIZE, ZEA MAYS L., INTO OAT, AVENA SATIVA L.

Submitted to: Maize Genetics Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 4, 2005
Publication Date: March 10, 2005
Citation: Kynast, R.G., Galatowitsch, M.W., Huettl, P.A., Cabral, C.B., Walch, M.D., Phillips, R.L., Rines, H.W. 2005. Sexual transfer of B-chromosomes from maize, Zea mays L., into oat, Avena sativa L. [abstract]. 47th Maize Genetics Conference Abstracts. p. 58.

Technical Abstract: B-chromosomes (B's) are supernumerary chromosomes described in several animal, fungal, and plant species. B's likely evolve from complements of autosomes (A-chromosomes, A's) and heterosomes (sex-chromosomes), and inherit species-specific structure and behavior. Although B's appear to be gene poor, relatively high numbers of B's can affect the fertility and fitness of the host genotype as reported in the intensely studied species Zea mays L. B's have not been reported in oat, Avena sativa L. From crosses of oat 'Starter' with a maize 'B73' derivative that carries B's from 'Black Mexican Sweet', out of 31 recovered F1-plants 14 tested positive for the maize repetitive element Grande-1. Two of the F1 plants had maize B's and no maize A's retained along with the haploid oat chromosome complement, based on positive assays for a B-specific marker that was obtained from J. Birchler, University of Missouri-Columbia, and absence of SSR-markers specific to each arm of the ten maize A's. In situ hybridization with labeled maize genomic DNA revealed two F1-plants that had one and three added maize B's, respectively. Twenty F2-offspring of each F1-plant were analyzed by cytological and molecular means. All F2-offspring of the F1-plant with one B lacked B's. The F1-plant with three B's produced three F2-plants with one B, six F2-plants with two B's, and eleven F2-plants with chimeric root meristems showing cells with one to five B's. All of the F2-plants with B's showed a regular 'Starter' oat phenotype with no distinct morphological characters. These oat plants with added maize B's separated from all maize A's provide an opportunity to investigate sequence uniqueness of B's and their possible evolutionary relationship to specific A's as well as transmission behavior of alien maize B's in an oat host.