Analysis of theNicotiana tabacumStigma/Style Transcriptome Reveals Gene Expression Differences between Wet and Dry Stigma Species    

Abstract

The success of plant reproduction depends on pollen-pistil interactions occurring at the stigma/style. These interactions vary depending on the stigma type: wet or dry. Tobacco (Nicotiana tabacum) represents a model of wet stigma, and its stigmas/styles express genes to accomplish the appropriate functions. For a large-scale study of gene expression during tobacco pistil development and preparation for pollination, we generated 11,216 high-quality expressed sequence tags (ESTs) from stigmas/ styles and created the TOBEST database. These ESTs were assembled in 6,177 clusters, from which 52.1% are pistil transcripts/ genes of unknown function. The 21 clusters with the highest number of ESTs (putative higher expression levels) correspond to genes associated with defense mechanisms or pollen-pistil interactions. The database analysis unraveled tobacco sequences homologous to the Arabidopsis (Arabidopsis thaliana) genes involved in specifying pistil identity or determining normal pistil morphology and function. Additionally, 782 independent clusters were examined by macroarray, revealing 46 stigma/style preferentially expressed genes. Real-time reverse transcription-polymerase chain reaction experiments validated the pistilpreferential expression for nine out of 10 genes tested. A search for these 46 genes in the Arabidopsis pistil data sets demonstrated that only 11 sequences, with putative equivalent molecular functions, are expressed in this dry stigma species. The reverse search for the Arabidopsis pistil genes in the TOBEST exposed a partial overlap between these dry and wet stigma transcriptomes. The TOBEST represents the most extensive survey of gene expression in the stigmas/styles of wet stigma plants, and our results indicate that wet and dry stigmas/styles express common as well as distinct genes in preparation for the pollination process.

Comparative Analysis of Pistil Transcriptomes Reveals Conserved and Novel Genes Expressed in Dry, Wet, and Semidry Stigmas

“…Additional data for pistil transcriptomes have also been generated recently in crocus (D'Agostino et al, 2007) and tobacco (Quiapim et al, 2009). The tobacco pistil EST data set was generated from stigma and style cDNA (Quiapim et al, 2009), and the crocus EST data set from stigma cDNA (D'Agostino et al, 2007). Comparisons of the results generated by these separate studies with our data set from S. squalidus showed broad correlations in the functional gene classes identified ( Fig.…”

“…Comparative Analyses of Wet, Dry, and Semidry Stigma/Style Transcriptomes When the data generated by this study were compared with data from Arabidopsis, tobacco, rice, and crocus, similarities and differences were revealed (Swanson et al, 2005;Tung et al, 2005;D'Agostino et al, 2007;Li et al, 2007;Quiapim et al, 2009). The study species differ in relatedness, pistil structure and function, and specific pollen-pistil processes, allowing the opportunity to assess consensus across diverse taxa (Supplemental Fig.…”

“…The rice data set was produced from analysis of an Affymetrix rice whole-genome array and cDNA microarray comparisons of stigma tissue (Li et al, 2007). Additional data for pistil transcriptomes have also been generated recently in crocus (D'Agostino et al, 2007) and tobacco (Quiapim et al, 2009). The tobacco pistil EST data set was generated from stigma and style cDNA (Quiapim et al, 2009), and the crocus EST data set from stigma cDNA (D'Agostino et al, 2007).…”

“…Large data sets have been generated to represent the transcriptomes of pollen and/or pistil tissues at different stages of development (Becker et al, 2003;Swanson et al, 2005;Tung et al, 2005;D'Agostino et al, 2007;Li et al, 2007;Quiapim et al, 2009).…”

Review Jasmonates are phytohormones with multiple functions, including plant defense and reproduction

“…Petit Havana SR-1 (Solanaceae), which are composed of stigma, style and ovary. To perform large-scale analysis of genes expressed in the tobacco pistil, we constructed and sequenced a stigma/style cDNA library generating the TOBEST database, which has been analyzed and described in a recent paper (Quiapim et al, 2009).…”