Isolation and Analysis of Gene Fragments from cDNA AFLPs that may be Involved in Programmed Cell death of Maize Endosperm
Authors:Stacey Darling-Novak, Avneet Nijjar
Mentor:Stacey Darling-Novak, Professor of Biology , University of La Verne
Maize is a widely adaptable and frequently used crop. Over the years, breeding programs have increased productivity, but small recent improvements suggest that yield increase using this technique has been maximized. Programmed cell death (PCD) is a genetically controlled process that occurs in the kernel endosperm during development. The normal timing of PCD may impede starch accumulation, thus delaying death would likely improve grain yield. Elucidating which transcripts are key to PCD will add to the understanding of this signal transduction pathway and may provide a means for genetically modifying maize such that endosperm cells can accumulate more starch before they die. Internucleosomal DNA fragmentation gels along with viability stains reveal that PCD occurs between18 and 28 days after pollination (DAP). Transcripts involved in the onset and persistence of PCD are up- or down-regulated during this time period. For this study, RNA was extracted from kernel endosperm of a developmental series, 18, 20, 24 and 28 DAP, cDNAs were generated and AFLP populations were made using selective primer sets. Six gene fragments from a primer set were identified as ones that showed differential gene expression throughout this developmental series. These fragments were removed from the gel using electro-elution and analyzed to better understand their potential role in the death process. Three gene fragments were analyzed with a NCBI BLAST. These fragments had homology to a 60S acidic ribosomal gene, a spermine synthase gene, and an α-zein gene.