Characterization of novel polymorphic genomic microsatellite markers of Boehmeria tricuspis (Hance) Makino.

In the present study, 59 polymorphic microsatellite loci of Boehmeria tricuspis (Hance) Makino were developed from the specific length amplified fragment sequencing data library of genome. The number of alleles per locus ranged from two to five, and the observed and expected heterozygosities ranged from 0.0000 to 1.0000 and from 0.0769 to 0.6751, respectively. Among the 59 loci, 25 displayed significant deviations from Hardy-Weinberg expectations (P < 0.05). The developed simple sequence repeat markers should be useful for studying population genetics in B. tricuspis (Hance) Makino, for providing further knowledge on its population differentiation, breeding system, and dispersal ability, as well as quantitative trait locus mapping. These markers could also be valuable genetic resources for closely related species.

Cloning of a phosphatidylinositol 4-kinase gene based on fiber strength transcriptome QTL mapping in the cotton species Gossypium barbadense.

Sea Island cotton (Gossypium barbadense) is highly valued for its superior fiber qualities, especially fiber strength. Based on a transcript-derived fragment originated from transcriptome QTL mapping, a fiber strength related candidate gene of phosphatidylinositol 4-kinase cDNA, designated as GbPI4K, was first cloned, and its expression was characterized in the secondary cell wall thickening stage of G. barbadense fibers. The ORF of GbPI4K was found to be 1926 bp in length and encoded a predicted protein of 641 amino acid residues. The putative protein contained a clear PI3/4K kinase catalytic domain and fell into the plant type II PI4K cluster in phylogenetic analysis. In this study, the expression of cotton PI4K protein was also induced in Escherichia coli BL21 (DE3) as a fused protein. Semi-quantitative RT-PCR analysis showed that the gene expressed in the root, hypocotyl and leaf of the cotton plants. Real-time RT-PCR indicated that this gene in Sea Island cotton fibers expressed 10 days longer than that in Upland cotton fibers, and the main expression difference of PI4K between Sea Island cotton and Upland cotton in fibers was located in the secondary cell wall thickening stage of the fiber. Further analysis indicated that PI4K is a crucial factor in the ability of Rac proteins to regulate phospholipid signaling pathways.