Genotype & phenotypic_image&data_2017_maize

Background : Drought threatens the food supply of the world population. Dissecting

the dynamic responses of plants to drought will be beneficial for breeding drought?

tolerant crops, as the genetic controls of these responses remain largely unknown.

Results : Here we develop a high-throughput multiple optical phenotyping system to

non-invasively phenotype 368 maize genotypes with or without drought stress over a

course of 98 days, and collected multiple optical images, including color camera

scanning, hyperspectral imaging and x-ray computed tomography images. We develop

high-throughput analysis pipelines to extract image-based traits (i-traits). Of these i?

traits, 10,080 were effective and heritable indicators of maize external and internal

drought responses. An i-trait-based genome wide association study reveals 4,322

significant locus-trait associations, representing 1,529 quantitative trait loci (QTLs) and

2,318 candidate genes, many that co-localize with previously reported maize drought

responsive QTLs. Expression QTL (eQTL) analysis uncovers many local and distant

regulatory variants that control the expression of the candidate genes. We use genetic

mutation analysis to validate two new genes, ZmcPGM2 and ZmFAB1A , which

regulate i-traits and drought tolerance. Moreover, the value of the candidate genes as

drought-tolerant genetic markers is revealed by genome selection analysis, and 15 i?

traits are identified as potential markers for maize drought tolerance breeding.

Conclusion : Our study demonstrates that combining high-throughput multiple optical

phenotyping and GWAS is a novel and effective approach to dissect the genetic

architecture of complex traits and clone drought-tolerance associated genes.