QTL Mapping Based on Different Genetic Systems for Essential Amino Acid Contents in Cottonseeds in Different Environments

Haiying Liu,Jinhong Chen,Shuijin Zhu,Chunhai Shi,Zhuangrong Huang,Alfred Quampah,Qiuling He,Jinrong Li

doi:10.1371/journal.pone.0057531

Abstract

Cottonseeds are rich in various essential amino acids. However, the inheritance of them at molecular level are still not defined across various genetic systems. In the present study, using a newly developed mapping model that can analyze the embryo and maternal main effects as well as QTL × environment interaction effects on quantitative quality trait loci (QTLs) in cottonseeds, a study on QTL located in the tetraploid embryo and tetraploid maternal plant genomes for essential amino acid contents in cottonseeds under different environments was carried out, using the immortal F2 (IF2) populations from a set of 188 recombinant inbred lines derived from an intraspecific hybrid cross of two upland cotton germplasms HS46 and MARKCBUCAG8US-1-88 as experimental materials. The results showed a total of 35 QTLs associated with these quality traits in cottonseeds. Nineteen QTLs were subsequently mapped on chromosome 5, 6 and 8 in sub-A genome and chromosome 15, 18, 22 and 23 in sub-D genome. Eighteen QTLs were also found having QTL × environment (QE) interaction effects. The genetic main effects from QTLs located on chromosomes in the embryo and maternal plant genomes and their QE effects in different environments were all important for these essential amino acids in cottonseeds. The results suggested that the influence of environmental factors on the expression of some QTLs located in different genetic systems should be considered when improving for these amino acids. This study can serve as the foundation for the improvement of these essential amino acids in cottonseeds.

Highlights

Cotton (Gossypium hirsutum L) is a leading fiber crop in the world producing annually both natural fiber and cottonseeds in large quantities
Ji et al [8] analyzed the genetic effects on amino acid content in the seeds of upland cotton and suggested that most amino acid compositions were mainly affected by the dominance effect
Little attention has been paid to its amino acid contents because of high cost involved in measuring these traits

Summary

Introduction

Cotton (Gossypium hirsutum L) is a leading fiber crop in the world producing annually both natural fiber and cottonseeds in large quantities. Cottonseed kernel is the most nutritious part possessing high oil (28.24–44.05%) and protein (27.83–45.6%) contents [2]. Literature reports the availability of seventeen different kinds of amino acids including essential amino acids like isoleucine, leucine, threonine, methionine, phenylalanine, and lysine in cottonseeds [3,4]. With the growing world population, the potential for its use as an important source of food is fairly high. For this reason, the improvement on cottonseed quality traits including its amino acid content by genetic breeding is becoming the need of hour. Most of the studies on cottonseeds have been focused on oil and gossypol contents [5], [6] with less emphasis on amino acids. Song and Zhang [9] identified QTL for seven amino acids using molecular marker technique, which was carried out only on one genetic system, i.e. embryo genome

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