Genomic resources of broomcorn millet: demonstration and application of a high-throughput BAC mapping pipeline

Wei Xu,Meizhong Luo,Xue Yang,Mengjie Liang,Hao Wang

doi:10.1186/s12863-021-01003-z

Abstract

BackgroundWith high-efficient water-use and drought tolerance, broomcorn millet has emerged as a candidate for food security. To promote its research process for molecular breeding and functional research, a comprehensive genome resource is of great importance.ResultsHerein, we constructed a BAC library for broomcorn millet, generated BAC end sequences based on the clone-array pooled shotgun sequencing strategy and Illumina sequencing technology, and integrated BAC clones into genome by a novel pipeline for BAC end profiling. The BAC library consisted of 76,023 clones with an average insert length of 123.48 Kb, covering about 9.9-fold of the 850 Mb genome. Of 9216 clones tested using our pipeline, 8262 clones were mapped on the broomcorn millet cultivar longmi4 genome. These mapped clones covered 308 of the 829 gaps left by the genome. To our knowledge, this is the only BAC resource for broomcorn millet.ConclusionsWe constructed a high-quality BAC libraray for broomcorn millet and designed a novel pipeline for BAC end profiling. BAC clones can be browsed and obtained from our website (http://eightstarsbio.com/gresource/JBrowse-1.16.5/index.html). The high-quality BAC clones mapped on genome in this study will provide a powerful genomic resource for genome gap filling, complex segment sequencing, FISH, functional research and genetic engineering of broomcorn millet.

Highlights

With high-efficient water-use and drought tolerance, broomcorn millet has emerged as a candidate for food security
bacterial artificial chromosome (BAC) library construction A BAC library of broomcorn millet was constructed with the restriction enzyme HindIII using high-molecularweight genomic DNA prepared from etiolated seedlings
Insert sizing of randomly picked clones showed that the majority of genomic BAC inserts fell into the length range of 97–145.5 kb with an average insert size of 132 kb (Fig. 1)

Summary

Introduction

With high-efficient water-use and drought tolerance, broomcorn millet has emerged as a candidate for food security. Broomcorn millet (Panicum miliaceum), known as proso millet, panic millet and wild millet, is one of the traditional five-grain crops in the north of China [1]. It is a typical C4 plant with high photosynthetic efficiency. Highquality chromosome-scale genome assemblies of two allotetraploid (2n = 4x = 36) broomcorn millet varieties decoded by Chinese researchers are available [8, 9]. These genome assemblies provide the foundation for the molecular breeding of broomcorn millet. Other genomic resources are still required to complete and make the full use of the genome assemblies

Methods

Results

Discussion

Conclusion