Construction and initial analysis of five Fosmid libraries of mitochondrial genomes of cotton (Gossypium)

Abstract

Cotton (Gossypium) is an important crop providing textile fiber and edible oil. To gain the insights into mechanism of the cytoplasmic male sterility (CMS) inheritance, we constructed five fosmid libraries of mitochondrial genomes from mitotype of G. harknessii Brandegee. (one CMS line and its restorer), mitotype of G. hirsutum L. (one CMS line and its maintainer), and G. barbadense L. The numbers of the clones in these libraries ranged from 1152 to 2016 with an average insert size of 36.2 to 38.4 kb, equivalent to 70–119.3 mitogenomes. The libraries were screened with 28 markers derived from the conservative sequences and yielded 22, 19, 26, 21, and 23 positive clones, respectively. These positive clones were used to construct the physical map of G. harknessii Brandegee. CMS line and G. barbadense L. mitogenomes that shared six syntenis regions. A total of 30 genes in nine clusters showed conservative and had high similarity with those in the mitochondrial genomes of cotton, Carica papaya, Cucurbita pepo and Nicotiana tabacum. Further investigation indicated that gene rrn26 had two copies in all five cotton mitogenomes, while genes atp1, rrn5 and rrn18 had two copies only in G. barbadense L. The positive clones and physical map are considered being useful resources in cotton genomics research.