Chandnani Rahul, Wang Baohua, Draye Xavier, Rainville Lisa K, Auckland Susan, Zhuang Zhimin, Lubbers Edward L, May O Lloyd, Chee Peng W, Paterson Andrew H
Plant Genome Mapping Laboratory, University of Georgia, 111 Riverbend Road, Athens, GA, 30605, USA.
NESPAL Molecular Cotton Breeding Laboratory, University of Georgia, Tifton, GA, 31793, USA.
Theor Appl Genet. 2017 Oct;130(10):2219-2230. doi: 10.1007/s00122-017-2952-y. Epub 2017 Aug 11.
This study reports transmission genetics of chromosomal segments into Gossypium hirsutum from its most distant euploid relative, Gossypium mustelinum . Mutilocus interactions and structural rearrangements affect introgression and segregation of donor chromatin. Wild allotetraploid relatives of cotton are a rich source of genetic diversity that can be used in genetic improvement, but linkage drag and non-Mendelian transmission genetics are prevalent in interspecific crosses. These problems necessitate knowledge of transmission patterns of chromatin from wild donor species in cultivated recipient species. From an interspecific cross, Gossypium hirsutum × Gossypium mustelinum, we studied G. mustelinum (the most distant tetraploid relative of Upland cotton) allele retention in 35 BCF plants and segregation patterns in BCF populations totaling 3202 individuals, using 216 DNA marker loci. The average retention of donor alleles across BCF plants was higher than expected and the average frequency of G. mustelinum alleles in BCF segregating families was less than expected. Despite surprisingly high retention of G. mustelinum alleles in BCF, 46 genomic regions showed no introgression. Regions on chromosomes 3 and 15 lacking introgression were closely associated with possible small inversions previously reported. Nonlinear two-locus interactions are abundant among loci with single-locus segregation distortion, and among loci originating from one of the two subgenomes. Comparison of the present results with those of prior studies indicates different permeability of Upland cotton for donor chromatin from different allotetraploid relatives. Different contributions of subgenomes to two-locus interactions suggest different fates of subgenomes in the evolution of allotetraploid cottons. Transmission genetics of G. hirsutum × G. mustelinum crosses reveals allelic interactions, constraints on fixation and selection of donor alleles, and challenges with retention of introgressed chromatin for crop improvement.
本研究报告了染色体片段从陆地棉最遥远的整倍体亲缘种——黄褐棉向陆地棉的遗传传递情况。多基因座相互作用和结构重排影响供体染色质的渐渗和分离。棉花的野生异源四倍体亲缘种是丰富的遗传多样性来源，可用于遗传改良，但连锁累赘和非孟德尔遗传传递在种间杂交中普遍存在。这些问题需要了解野生供体物种的染色质在栽培受体物种中的传递模式。通过陆地棉×黄褐棉的种间杂交，我们利用216个DNA标记位点，研究了35株回交导入系（BCF）植株中黄褐棉（陆地棉最遥远的四倍体亲缘种）等位基因的保留情况，以及BCF群体（共3202个个体）中的分离模式。BCF植株中供体等位基因的平均保留率高于预期，而在BCF分离群体中黄褐棉等位基因的平均频率低于预期。尽管BCF中黄褐棉等位基因的保留率高得出奇，但仍有46个基因组区域未发生渐渗。3号和15号染色体上缺乏渐渗的区域与先前报道的可能的小倒位密切相关。在单基因座分离畸变的基因座之间以及来自两个亚基因组之一的基因座之间，非线性双基因座相互作用很常见。将本研究结果与先前研究结果进行比较表明，陆地棉对来自不同异源四倍体亲缘种的供体染色质具有不同的渗透性。亚基因组对双基因座相互作用的不同贡献表明，在异源四倍体棉花的进化过程中，亚基因组的命运不同。陆地棉×黄褐棉杂交的遗传传递研究揭示了等位基因相互作用、供体等位基因固定和选择的限制，以及为作物改良保留渐渗染色质所面临的挑战。
