Genome-wide analysis of deletions in maize population reveals abundant genetic diversity and functional impact

Authors: ZHANG, XIAO - Sichuan Agricultural University; ZHU, YONGHUI - Sichuan Academy Of Agricultural Science; KREMLING, KARL - Cornell University; ROMAY, CINTA - Cornell University; BUKOWSKI, ROBERT - Cornell University; SUN, QI - Cornell University; GAO, SHIBIN - Sichuan Agricultural University; Buckler, Edward - Ed; LU, FEI - Chinese Academy Of Sciences

Submitted to: Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 9/30/2021
Publication Date: 10/18/2021
Citation: Zhang, X., Zhu, Y., Kremling, K.A., Romay, C., Bukowski, R., Sun, Q., Gao, S., Buckler Iv, E.S., Lu, F. 2021. Genome-wide analysis of deletions in maize population reveals abundant genetic diversity and functional impact. Theoretical and Applied Genetics. https://doi.org/10.1007/s00122-021-03965-1.
DOI: https://doi.org/10.1007/s00122-021-03965-1

Interpretive Summary: Structural variation (SV) contributes to phenotypic diversity in plants and prior studies confirm that SV is pervasive in the maize genome. Deletion, which occurs when there is a loss of genetic material, is one type of SV that may impact gene expression and cause phenotypic differences. In this study, deletions in the whole-genome sequencing data of 270 maize inbred lines were analyzed. The deletions explained population structure well and correlated with expression levels and other genomic features. Deletions and SNPs can be combined to study expression variation and the genetic architecture of phenotypic traits. Our findings will provide insights into characteristic and biological function of genome-wide deletions in maize.

Technical Abstract: Many studies have confirmed that structural variation (SV) is pervasive throughout the maize genome. Deletion is one type of SV that may impact gene expression and cause phenotypic changes in quantitative traits. In this study, two read count approaches were used to analyze the deletions in the whole-genome sequencing data of 270 maize inbred lines. A total of 19,754 deletion windows overlapped 12,751 genes, which were unevenly distributed across the genome. The deletions explained population structure well and correlated with genomic features. The deletion proportion of genes was determined to be negatively correlated with its expression. The detection of gene expression quantitative trait loci (eQTL) indicated that local eQTL were fewer but had larger effects than distant ones. The common associated genes were related to basic metabolic processes, whereas unique associated genes with eQTL played a role in the stress or stimulus responses in multiple tissues. Compared with the eQTL detected by SNPs derived from the same sequencing data, 89.4% of the associated genes could be detected by both markers. The effect of top eQTL detected by SNPs was usually larger than that detected by deletions for the same gene. A genome-wide association study (GWAS) on flowering time and plant height illustrated that only a few loci could be consistently captured by SNPs, suggesting that combining deletion and SNP for GWAS was an excellent strategy to dissect trait architecture. Our findings will provide insights into characteristic and biological function of genome-wide deletions in maize.