QTL Mapping Low-Temperature Germination Ability in the Maize IBM Syn10 DH Population.

Qinghui Han,Guangwu Zhao,Qingxiang Zhu,Yao Shen,Thomas Lübberstedt,Michael Lee

doi:10.3390/plants11020214

Abstract

Chilling injury poses a serious threat to seed emergence of spring-sowing maize in China, which has become one of the main climatic limiting factors affecting maize production in China. It is of great significance to mine the key genes controlling low-temperature tolerance during seed germination and study their functions for breeding new maize varieties with strong low-temperature tolerance during germination. In this study, 176 lines of the intermated B73 × Mo17 (IBM) Syn10 doubled haploid (DH) population, which comprised 6618 bin markers, were used for QTL analysis of low-temperature germination ability. The results showed significant differences in germination related traits under optimum-temperature condition (25 °C) and low-temperature condition (10 °C) between two parental lines. In total, 13 QTLs were detected on all chromosomes, except for chromosome 5, 7, 10. Among them, seven QTLs formed five QTL clusters on chromosomes 1, 2, 3, 4, and 9 under the low-temperature condition, which suggested that there may be some genes regulating multiple germination traits at the same time. A total of 39 candidate genes were extracted from five QTL clusters based on the maize GDB under the low-temperature condition. To further screen candidate genes controlling low-temperature germination, RNA-Seq, in which RNA was extracted from the germination seeds of B73 and Mo17 at 10 °C, was conducted, and three B73 upregulated genes and five Mo17 upregulated genes were found by combined analysis of RNA-Seq and QTL located genes. Additionally, the variations of Zm00001d027976 (GLABRA2), Zm00001d007311 (bHLH transcription factor), and Zm00001d053703 (bZIP transcription factor) were found by comparison of amino sequence between B73 and Mo17. This study will provide a theoretical basis for marker-assisted breeding and lay a foundation for further revealing molecular mechanism of low-temperature germination tolerance in maize.

Highlights

Introduction iationsAs an important grain, forage and industrial raw material, maize planting area ranks first in worldwide
The data showed that the value of each trait of between the amino sequence of Zm00001d053703 (B73) and Mo17 was significantly different at 10 ◦ C (Figure 1), which suggested that they were suitable as parent materials for mapping the quantitative trait loci (QTL) related to low-temperature germination ability
Compared with Mo17, the average values of all traits of intermated B73 × Mo17 (IBM) Syn10 doubled haploid (DH) population were closer to B73 at the low temperature (Table 1)

Summary

Introduction

Forage and industrial raw material, maize planting area ranks first in worldwide. The germination and growth of maize, which was originated from tropical and subtropical areas, were seriously threatened by chilling injury in early spring. Germination rate was decreased in maize, while the elongation of plumule length, seedling length, and root length were inhibited [1]. The low seed vigor and poor low-temperature tolerance of cultivated varieties had led to irregular emergence and seedling absent in early spring. In order to cope with low temperatures, mulch film was used to avoid the injury of low temperatures in production, but which had the shortcoming of high cost and residue contamination. Cultivation of new maize varieties with strong low-temperature germination ability will be the fundamental way to improve maize germination rate in early spring [2]. The breeding progress of maize was Licensee MDPI, Basel, Switzerland

Methods

Results

Conclusion