Genome-Wide Association Study of Vascular Bundle-Related Traits in Maize Stalk.

Yunxiao Zheng,Weibin Song,Han Liu,Yaqun Huang,Peng Hou,Jinjie Guo,Hong Wang,Liying Zhu

doi:10.3389/fpls.2021.699486

Abstract

The vascular bundle plays an important role in nutrient transportation in plants and exerts great influence on crop yield. Maize is widely used for food, feed, and fuel, producing the largest yield in the world. However, genes and molecular mechanism controlling vascular bundle-related traits in maize have largely remained undiscovered. In this study, a natural population containing 248 diverse maize inbred lines genotyped with high-throughput SNP markers was used for genome-wide association study. The results showed that broad variations existed for the vascular bundle-related traits which are subject to genetic structure and it was suitable for association analysis. In this study, we identified 15, 13, 2, 1, and 5 SNPs significantly associated with number of small vascular bundle, number of large vascular bundle, average area of single small vascular bundle, average area of single large vascular bundle, and cross-sectional area, respectively. The 210 candidate genes in the confidence interval can be classified into ten biological processes, three cellular components, and eight molecular functions. As for the Kyoto Encyclopedia of Genes and Genomes analysis of the candidate genes, a total of six pathways were identified. Finally, we found five genes related to vascular development, three genes related to cell wall, and two genes related to the mechanical strength of the stalk. Our results provide the further understanding of the genetic foundation of vascular bundle-related traits in maize stalk.

Highlights

Maize is the most widely planted crop in the world and provides a large part of food for animals and human as well as materials for deep processing and energy
The statistical data for number of small vascular bundle (NSVB), number of large vascular bundle (NLVB), area of single small vascular bundle (ASVB), area of single large vascular bundle (ALVB), and cross-sectional area (CSA) across the five environments showed that all five vascular bundle-related traits showed a normal distribution (Figure 2)
The broad-sense heritability for NSVB, NLVB, ASVB, ALVB, and CSA across the five environments in the 248 inbred lines ranged from 46.49% (ASVB) to 91.52% (NLVB), indicating the predominant role of genetic factors for these traits (Table 2)

Summary

Introduction

Maize is the most widely planted crop in the world and provides a large part of food for animals and human as well as materials for deep processing and energy. According to the forecast of the United Nations, the world’s population will exceed nine billion and global demand for maize will double (Ray et al, 2013) by 2050. In order to provide living space for the growing population, the cultivated land area has shrunk year by year worldwide. It is of great significance to increase the yield per unit area of maize. Vascular bundles provide mechanical support for plants. Previous studies have observed significant correlation between the vascular bundle system and maize yield (Housley and Peterson, 1982; Nátrová, 1991)

Methods

Results

Conclusion