Capsaicinoids are responsible for the burning sensation or pungency in hot peppers (Capsicum spp.). These compounds enable the resistance of Capsicum plants to diseases like Fusarium and the plant seeds' dissemination by birds, which cannot detect the pungency. Consumers mainly use hot peppers as vegetable and food additive. Capsaicinoid is mainly controlled by the Pun1 gene and is also affected by quantitative trait loci (QTLs). Researchers have conducted studies on these loci, but have not identified useful candidate genes for the trait. 

Scientist Byoung-Cheorl Kang and colleagues from Seoul National University and Rural Development Administration in South Korea used QTL mapping and Genome-wide association (GWAS) to detect QTLs for capsaicinoid content in Capsicum. Recombinant inbred lines produced from parentals "Perennial" (pungent small pepper line) and "Dempsey" (nonpungent bell pepper cultivar) are used in the experiment. They found five candidate genes controlling capsaicinoid content using their experimental data and previously available data. These genes include pAMT, C4H, 4CL, CSE, and FatA from the phenylpropanoid and fatty acid pathways. These genes will be useful in elucidating the mechanism of capsaicinoid biosynthesis and in breeding for high-pungency peppers.

For more information, read the research article in Plant Biotechnology Journal.