Submitted to: Biologia
Publication Type: Peer reviewed journal
Publication Acceptance Date: 3/15/2013
Publication Date: 4/1/2013
Citation: Cai, Y., Sun, Q., Li, S., Chen, M., He, Z., Jiang, H., Yuan, Y., Shi, Y., Liu, J. 2013. Identification of the genes and pathways associated with pigment gland morphogenesis in cotton by transcriptome profiling of near-isogenic lines. Biologia. 68(2):249-257. Interpretive Summary: Cottonseed protein is underutilized due to the presence of pigment glands containing a toxic compound called gossypol. Gossypol and related compounds in various tissues protect the cotton plants against attack from pathogens, insects, and rodents. Understanding the mechanism of cotton pigment gland formation and the regulation of gossypol biosynthesis will greatly facilitate research efforts in developing a cotton variety with a gossypol free seed but with normally glanded foliage. We identified 880 genes associated with gland morphogenesis in cotton by comparing genes turned-on in tissues containing pigment glands in normally glanded cotton versus the same tissue in closely related lines that lack glands. Analysis of these genes provided useful information on the molecular mechanism and regulation of gland formation and the related processes in cotton. This will help us understand the complicated mechanism of gland development and guide our breeding of a disease resistant cotton plant with seed that contain no harmful gossypol for feed or food.
Technical Abstract: Cottonseed protein is underutilized due to the presence of pigment gland containing a toxic compound called gossypol. Cotton produce gossypol and related compounds in various tissues to protect itself against microbial, insect, and rodent attacks. Understanding the mechanism of cotton pigment gland formation and the regulation of gossypol biosynthesis will greatly facilitate research efforts in developing a cotton variety with a gossypol free seed and normally glanded foliage. We identified 880 differentially expressed genes associated with gland morphogenesis in cotton by comparing transcriptome profile of cotton tissues containing pigment glands from glandless and glanded near-isogenic lines using a GeneChip. Gene ontology (GO) analysis showed that 880 genes were distributed mainly among the following GO categories: cellular process (14.45%), physiological process (14.23%), catalytic activity (9.21%), metabolism (8.99%), and cell parts (5.24%). Molecular pathway analysis revealed that these differentially expressed genes were involved in 58 KEGG pathways. Differentially expressed genes were also identified and isolated using suppression subtractive hybridization (SSH) from the cotton gland forming tissues of the same near-isogenic lines. A total of 147 ESTs were identified whose expression was either up- or down-regulated. Sequencing and BLAST analysis indicated that some of these genes were novel, while others were related to energy metabolism, transcription factors, and biotic responses. Thirteen genes were found to be differentially expressed both in SSH and GeneChip analysis. The expression pattern of these genes was verified by real-time PCR. The gene expression profiles produced in this study provide useful information on the molecular mechanism and regulation of gland formation and the related process in cotton. Of particular interest for future study are the genes identified by both SSH and GeneChip analysis. The outcomes are helping for our understanding of the development of specialized structures such as trichomes in plant species, from an applied and basic science perspective and promoting the application in molecular breeding.