|Curtiss, Jessica -|
|Stewart, James -|
|Zhang, Jinfa -|
Submitted to: Plant Cell Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 30, 2011
Publication Date: November 23, 2011
Citation: Curtiss, J., Turley, R.B., Stewart, J.M., Zhang, J. 2011. Comparative analysis of gene expression between semigametic Pima 57-6 and non-semigametic Pima S-1 in cotton by differential display. Plant Cell Reports. 30:643-653. Interpretive Summary: Hybrid vigor is a commonly described phenomenon in which the offspring of a cross between two different parent plants produces a better quality product, e.g., higher yields, improved flavor, or longer fiber. Cotton breeding and seed production, however, is a time consuming, labor intensive process which restricts the use of hybrid vigor to develop improved cotton quality. The development of semigametic plants (plants which do not produce live pollen) could be used to naturally produce hybrids by insect pollination at an affordable cost. This study identifies numerous genes which are possibly involved in the development of semigametic cotton plants using a method to identify differences in the DNA. Identifying the gene and it's manipulation could lead to the widespread use of hybrid vigor in cotton plants and would revolutionize the industry.
Technical Abstract: Semigamy in cotton is a type of facultative apomixis controlled by a single incompletely dominant gene (Se) in which the sperm and egg nuclei fail to fuse after the sperm nucleus has entered the embryo sac, giving rise to diploid, haploid or even chimeral embryos comprised of paternal and maternal origins. In this study employing the mRNA differential display (DD) technique using semigametic 57-4 in comparison to its non-semigametic progenitor Pima S-l, over 70 differentially displayed cDNA fragments were isolated, of which some fragments exhibited semigamy specific expression across anthers and/or ovules. Of the sixty-one (61) cDNA fragments cloned and sequenced, two showed high homology to alpha- and beta-tubulin genes, and another high homology to a kinesin motor protein. From cDNA-single strand conformational polymorphism (cDNA-SSCP) using primers designed from DD sequences, six expression polymorphisms between the semigametic and non-semigametic genotypes were observed. From a quantitative reverse transcription PCR reaction (qRT-PCR) using a primer pair designed from a differentially displayed alpha-tubulin sequence, the gene was found to be significantly down-regulated, approximately a 2-fold decrease in expression, in semigametic anthers. This study represents the first attempt to understand the molecular mechanism of semigamy towards the isolation and characterization of the semigamy gene in cotton.