Starch biosynthesis during pollen maturation is associated with altered patterns of gene expression in maize.
Starch biosynthesis during pollen maturation is not well understood in terms of genes/proteins and intracellular controls that regulate it in developing pollen. We have studied two specific developmental stages: "early," characterized by the lack of starch, before or during pollen mitosis I; and "late," an actively starch-filling post-pollen mitosis I phase in S-type cytoplasmic male-sterile (S-CMS) and two related male-fertile genotypes. The male-fertile starch-positive, but not the CMS starch-deficient, genotypes showed changes in the expression patterns of a large number of genes during this metabolic transition. In addition to a battery of housekeeping genes of carbohydrate metabolism, we observed changes in hexose transporter, plasma membrane H(+)-ATPase, ZmMADS1, and 14-3-3 proteins. Reduction or deficiency in 14-3-3 protein levels in all three major cellular sites (amyloplasts [starch], mitochondria, and cytosol) in male-sterile relative to male-fertile genotypes are of potential interest because of interorganellar communication in this CMS system. Further, the levels of hexose sugars were significantly reduced in male-sterile as compared with male-fertile tissues, not only at "early" and "late" stages but also at an earlier point during meiosis. Collectively, these data suggest that combined effects of both reduced sugars and their reduced flux in starch biosynthesis along with a strong possibility for altered redox passage may lead to the observed temporal changes in gene expressions, and ultimately pollen sterility.
Datta
Rupali
R
Program in Plant Molecular and Cellular Biology, University of Florida, Gainesville, Florida 32611-0680, USA.
Chamusco
Karen C
KC
Chourey
Prem S
PS
D048948:14-3-3 Proteins; D050260:Carbohydrate Metabolism; D002455:Cell Division / Q000187:drug effects; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005452:Fluoresceins / Q000494:pharmacology; D018507:Gene Expression Regulation, Developmental; D018506:Gene Expression Regulation, Plant; D015151:Immunoblotting; D026161:MADS Domain Proteins / Q000235:genetics / Q000378:metabolism; D008938:Mitosis / Q000235:genetics; D009004:Monosaccharide Transport Proteins / Q000235:genetics / Q000378:metabolism; D010940:Plant Proteins / Q000235:genetics / Q000378:metabolism; D011058:Pollen / Q000254:growth & development* / Q000378:metabolism; D011193:Potassium Iodide / Q000494:pharmacology; D006180:Proton-Translocating ATPases / Q000235:genetics / Q000378:metabolism; D018749:RNA, Plant / Q000235:genetics / Q000378:metabolism; D013213:Starch / Q000096:biosynthesis*; D014446:Tyrosine 3-Monooxygenase / Q000235:genetics / Q000378:metabolism; D003313:Zea mays / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism
D048948:14-3-3 Proteins; D004268:DNA-Binding Proteins; D005452:Fluoresceins; C091848:GRF1 protein, Zea mays; D026161:MADS Domain Proteins; D009004:Monosaccharide Transport Proteins; D010940:Plant Proteins; D018749:RNA, Plant; D011193:Potassium Iodide; D013213:Starch; D014446:Tyrosine 3-Monooxygenase; D006180:Proton-Translocating ATPases; C018506:diacetylfluorescein