Construction of Gossypium barbadense Mutant Library Provides Genetic Resources for Cotton Germplasm Improvement.

Muhammad Ali Abid,Peilin Wang,Sandui Guo,Chengzhen Liang,Tao Zhu,Zhigang Meng,Rui Zhang,Waqas Malik

doi:10.3390/ijms21186505

Abstract

Allotetraploid cotton (Gossypium hirsutum and Gossypium barbadense) are cultivated worldwide for its white fiber. For centuries, conventional breeding approaches increase cotton yield at the cost of extensive erosion of natural genetic variability. Sea Island cotton (G. barbadense) is known for its superior fiber quality, but show poor adaptability as compared to Upland cotton. Here, in this study, we use ethylmethanesulfonate (EMS) as a mutagenic agent to induce genome-wide point mutations to improve the current germplasm resources of Sea Island cotton and develop diverse breeding lines with improved adaptability and excellent economic traits. We determined the optimal EMS experimental procedure suitable for construction of cotton mutant library. At M6 generation, mutant library comprised of lines with distinguished phenotypes of the plant architecture, leaf, flower, boll, and fiber. Genome-wide analysis of SNP distribution and density in yellow leaf mutant reflected the better quality of mutant library. Reduced photosynthetic efficiency and transmission electron microscopy of yellow leaf mutants revealed the effect of induced mutations at physiological and cellular level. Our mutant collection will serve as the valuable resource for basic research on cotton functional genomics, as well as cotton breeding.

Highlights

Identification of novel alleles in cotton has taken an immense importance in facilitating the genetic improvement and functional genomics research
Chemical mutagenesis has demonstrated to be an effective tool to create a wide range of phenotypic variations in both diploid and tetraploid Gossypium populations [7,9,11]
We demonstrated the potential of EMS-induced mutagenesis to create a vast mutant library of G. barbadense and induced genetic variability can be used to identify gene-regulating important phenotypes

Summary

Introduction

Identification of novel alleles in cotton has taken an immense importance in facilitating the genetic improvement and functional genomics research. Conventional breeding approaches have made enormous contributions to the cultivation of cotton varieties; increasing biased manipulation of available genetic variability in cotton germplasm resources has resulted in great loss of genetic potential and increased vulnerability to many insect/pests [1]. This selection pressure has reduced the allelic diversity and hampers the efforts to improve the agronomic traits of cotton and limit our understanding about the molecular mechanisms that respond to environmental stresses and pathogens [2]. Mutagen doses inducing about 50% lethality (LD50) among M1 plants are considered as appropriate dose because of their high mutation frequency [14]

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Conclusion