Sugary enhancer1 (se1) Gene Endosperm Dosage and Sweet Corn Carbohydrate Content

Abstract

Inbreds IL451b sugary1 (su1) and IL678a su1 isogenic for the sugary enhancer1 (se1) gene mutation were used to analyze the relationship between se1 gene dosage and endosperm sugar content. Each line was self-pollinated and reciprocal crosses were made between the isolines of each genotype to produce se1 gene dosages of 0, 1, 2, and 3 in the triploid endosperm. Ears were harvested at 15, 18, 21, 24, 27, and 45 days after pollination (DAP). Whole kernels were freeze-dried, ground into powder, and stored at –80°C until subsequent chemical analyses. Sucrose, glucose and fructose were analyzed using high-pressure liquid chromatography (HPLC), the results of which indicated a significant increase in kernel sugar content when the se1 allele is homozygous. \batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \[\begin{array}{lcl}&\underline{\mathrm{Sucrose\ content\ at}{\ }21{\ }\mathrm{DAP}(\%{\ }\mathrm{dry}{\ }\mathrm{wt})}&\\\underline{se1{\ }\mathrm{dose}}&\underline{\mathrm{IL}{\ }451\mathrm{b}}&\underline{\mathrm{IL}{\ }678\mathrm{a}}\\0&9.6&10.3\\1&8.0&10.7\\2&11.3&10.9\\3&15.8&12.2\end{array}\] \end{document} Sucrose content at 21 DAP (typical maturity for harvesting) was observed to increase in the IL451b and IL678a backgrounds from zero to three doses of se1 by 65% and 18% respectively, indicating that this mutation varies in its expression in different genetic backgrounds. Associations between kernel phytoglycogen and starch content and se1 gene dosage are presented. The biochemical lesion associated with the se1 gene product is discussed.