Genetic Loci Controlling Carotenoid Biosynthesis in Diverse Tropical Maize Lines. Issue 3 (1st March 2018)

• Record Type: Journal Article
• Authors: Azmach, Girum; Menkir, Abebe; Spillane, Charles; Gedil, Melaku
• Is Part Of: G3. Volume 8:Issue 3(2018)
• Page Start: 1049
• Page End: 1065
• Publication Date: 2018-03-01
• Subjects: vitamin A deficiency -- provitamin A -- linkage disequilibrium (LD) -- mixed linear model (MLM) -- genotyping by sequencing (GBS) -- biofortification -- maize; Genetics -- Research -- Periodicals; Genomics -- Periodicals; Genetics; Genomics; Genes; Genetics -- Research; Genomics; Electronic journals; Periodical; Periodicals; Fulltext; Internet Resources; Periodicals; 572.8
• DOI: 10.1534/g3.117.300511
• Languages: English
• ISSNs: 2160-1836

Abstract

Abstract: The discovery and use of genetic markers associated with carotenoid levels can help to exploit the genetic potential of maize for provitamin A accumulation more effectively. Provitamin A carotenoids are classes of carotenoids that are precursors of vitamin A, an essential micronutrient in humans. Vitamin A deficiency is a global public health problem affecting millions of people, especially in developing countries. Maize is one of the most important staple crops targeted for provitamin A biofortification to help alleviate vitamin A deficiency in developing countries. A genome-wide association study (GWAS) of maize endosperm carotenoids was conducted using a panel of 130 diverse yellow maize tropical inbred lines genotyped with Genotyping by Sequencing (GBS) SNP markers. Numerous significant association signals co-localizing with the known carotenoid biosynthesis genes crtRB1, lcyE and ZEP1 were identified. The GWAS confirmed previously reported large effects of the two major carotenoid biosynthesis genes lcyE and crtRB1 . In addition, significant novel associations were detected for several transcription factors ( e.g., RING zinc finger domain and HLH DNA-binding domain super family proteins) that may be involved in regulation of carotenoid biosynthesis in maize. When the GWAS was re-conducted by including the major effects of lcyE and crtRB1 genes as covariates, a SNP in a gene coding for an auxin response factor 20 transcription factor was identified which displayed an association with β-carotene and provitamin A levels. Our study provides a foundation for design and implementation of genomics-assisted selection strategies for provitamin A maize breeding in tropical regions, and advances efforts toward identification of additional genes (and allelic variants) involved in the regulation of carotenoid biosynthesis in plants.