Characterization of the Roles of Kafirin Genes in Sorghum Grain Quality

Sorghum (S. bicolor) is globally recognized for its agricultural importance, primarily used for animal feed and biofuel production. However, problems with low calorific and nutritional contents limit its potential as a food product. One major cause of these limitations is the low content and digestibility of storage proteins in the sorghum grain. Kafirin encoded by 25 genes constitutes a substantial portion (approximately 77-82%) of the protein bodies within the sorghum endosperm. This project aims to systematically understand each kafirin gene's role in the grain quality by characterizing kafirin gene mutants. From our large-scale mutants, we have isolated the homozygous mutants for each kafirin gene. Utilizing single kernel characterization system (SKCS) and nuclear infrared spectroscopy (NIR), we observed alterations in kernel hardness, weight, and size across all kafirin mutants. Our investigation revealed changed protein content and digestibility in the mutants compared to the wild type. Alpha kafirin-9 exhibited the lowest digestibility, whereas gamma kafirin 23 displayed the highest digestibility compared to BTx623. Scanning electron microscopy analysis of mutant lines, including the wild type, revealed morphological changes in both floury and vitreous endosperm. High-performance liquid chromatography (HPLC) confirmed the absence of gamma kafirin peaks, validating the knockout mutation. This comprehensive study enhances our understanding of kafirin's impact on sorghum grain quality, potentially facilitating significant advancements in food security and nutrition.

Embargo status: Restricted until 06/2025. To request the author grant access, click on the PDF link to the left.