Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/7/2005
Publication Date: 5/10/2005
Citation: Wu, Z., Soliman, K.M., Zipf, A., Saha, S., Sharma, G.C., Jenkins, J.N. 2005. Isolation and characterization of genes differentially expressed in fiber of Gossypium barbadense L. Journal of Cotton Science. 9:166-174. Interpretive Summary: There is a need for improved fiber quality to meet the demands of high speed fiber spinning equipment. The genes involved in fiber improvement are not clearly known. This research clones and sequences some of the genes involved in fiber quality. Messenger RNA from fiber of an upland cotton (Gossypium hirsutum, TM-1) line and a long staple cotton (G. Barbadense, 3-79) line were extracted. A cDNA library was constructed from the long staple cotton line. It was screened with cDNA probes from each cotton line. Five cDNA clones were expressed at a high level in 20 day post-anthesis fiber tissue of the long staple line. Sequence analysis indicated the presence of a cotton lipid transfer protein (GbLTP), a mitogen-activated protein kinase (GbMAPK) and a novel gene with no homologous sequence (GbFb1) in the Genbank database. Two remaining cDNA sequences (GbFb2 and GbFb3) showed high identity in nucleotide sequences to 7-10 day post-anthesis G. hirsutum and 6 day post-anthesis G. arboretum fiber cDNA's respectively, but of unknown function. The genes for all cDNA's except GbFb1 showed higher levels in fiber than in other tissue tested. These cDNA clones differentially expressed in the long staple cotton were presumed to be associated with cotton fiber quality, but their specific contributions have not been determined. This result is one of a few reports related to fiber-associated gene expression in long staple G. barbadense cotton.
Technical Abstract: Due to the widespread use of high speed spinning technology in the yarn and textile industry, the demand for high strength fiber in raw cotton has increased. Improvement of cotton fiber quality through conventional breeding is limited because of the complexity of fiber quality genetics. Hence, the primary goal of this project was to identify and characterize genes related to cotton fiber quality. Messenger RNAs were isolated from the fiber of high yielding cotton TM-1 (Gossypium hirsutum) and high fiber quality cotton 3-79 (G. barbadense), respectively. A cDNA library was constructed from the high fiber-quality line, 3-79, and screened differentially with the cDNA probes obtained from mRNAs of TM-1 and 3-79, respectively. Thirteen cDNA clones were selected and subjected to northern hybridization analysis. Five of the thirteen cDNAs (GbFb1, GbFb2, GbFb3, GbMAPK and GbLTP) were highly expreseed in the twenty day-post-anthesis (dpa) fiber tissue of 3-79 cotton. Sequence analysis indicated the presence of a cotton lipid transfer protein (GbLTP), a mitogen-activated protein kinase (GbMAPK) and a novel gene with no homologous sequence (GbFb1) in the Genbank database. The remaining two separate cDNAs (GbFb2 and GbFb3) showed high identity in nucleotide sequence to 7-10 dpa G. hirsutum and 6-day G. arboreum fiber cDNAs, respectively, but of unknown functions. Expression of these five fiber-associated genes was developmentally regulated, but not tissue-specific. The genes for all the five cDNAs showed much higher levels of expression in the fiber than in the other tissues tested with the exception of the gene for GbFb1 in the flower. The expression of the GbMAPK gene in 3-79 fibers was lower during early fiber development (10 to 15 dpa) and higher in the latter stages (20 to 25 dpa). The expression of the other four genes, including GbLTP, was highest between 10 to 15 dpa, and decreased at 20 to 25 dpa. The cDNA clones differentially expressed in the 3-79 cotton fiber were presumed to be associated with cotton fiber quality, but their specific contributions have not been determined. The result presented here is among a few reports related to fiber-associated gene expression in G. barbadense