Genetic Loci Controlling Carotenoid Biosynthesis in Diverse Tropical Maize Lines

G3: Genes, Genomes, Genetics

Abebe Menkir^3¹  Charles Spillane^2²  Girum Azmach^1,2,3³ 

[1] Genetics and Biotechnology Laboratory, Plant and AgriBiosciences Research Centre, Ryan Institute, National University of Ireland Galway, H91 REW4, Ireland^2;International Institute of Tropical Agriculture, PMB 5320, Ibadan, Nigeria^3;Maize Breeding and Genetics Division, Bako National Maize Research Center, Ethiopian Institute of Agricultural Research, Bako, Ethiopia^1

关键词: vitamin A deficiency;    provitamin A;    linkage disequilibrium (LD);    mixed linear model (MLM);    genotyping by sequencing (GBS);    biofortification;    maize;   

DOI  :  10.1534/g3.117.300511

学科分类：生物科学（综合）

来源: Genetics Society of America

【 摘 要 】

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.

【 授权许可】

CC BY