ARS | Publication request: EXPRESSION OF C4 PHOTOSYNTHETIC CHARACTERISTICS IN OAT-MAIZE ADDITION LINES

Submitted to: Maize Genetics Conference Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: February 4, 2005
Publication Date: March 10, 2005
Citation: Kowles, R.V., Minnerath, J.M., Phillips, R.L., Rines, H.W. 2005. Expression of C4 photosynthetic characteristics in oat-maize addition lines [abstract]. 47th Maize Genetics Conference Abstracts. p. 21.

Technical Abstract: Oat-maize addition lines have been successfully generated, and they are available for every maize chromosome, 1 through 10. Addition lines are oat plants (C3 photosynthesis) that include one or more chromosomes from maize (C4 photosynthesis). These oat-maize addition lines may be useful to determine the extent to which individual maize chromosomes contribute to C4 photosynthesis and for the identification of the precise chromosomal regions involved in C4 photosynthesis. Investigations have been conducted that focused on the expression of several C4 enzymes and C4 leaf morphological characteristics in these oat-maize addition lines. Immunoblotting with polyclonal antibodies against phosphoenolpyruvate carboxylase (PEPc) and pyruvate orthophosphate dikinase (PPDK) on leaf protein extracts confirmed the location of the PEPc gene to chromosome 9 and the gene for PPDK to chromosome 6. Assays with leaf extracts showed activity of the enzymes in the oat-maize chromosome 9 and 6 lines, respectively. Indirect immunocytological tests with monoclonal antibodies showed widespread gene expression for PEPc in mesophyll cells of the oat-maize chromosome 9 line and PPDK in mesophyll cells of the oat-maize chromosome 6 line. Cytological investigations with cryostat microtomed leaf tissue indicated marked differences in cellular leaf structure, chloroplast size, and leaf attachment in the oat-maize chromosome 3 line. The production of suberin, another C4 characteristic, appeared to occur in the oat-maize chromosome 4 line. These results demonstrate that oat plants containing alien maize chromosomes exhibit both enzymatic and morphological C4 photosynthetic characteristics.