Dissection of the style's response to pollination using transcriptome profiling in self-compatible (Solanum pimpinellifolium) and self-incompatible (Solanum chilense) tomato species.

Panfeng Zhao,Lida Zhang,Lingxia Zhao

doi:10.1186/s12870-015-0492-7

Abstract

BackgroundTomato (Solanum lycopersicum) self-compatibility (SC) is defined as self-pollen tubes that can penetrate their own stigma, elongate in the style and fertilize their own ovules. Self-incompatibility (SI) is defined as self-pollen tubes that are prevented from developing in the style. To determine the influence of gene expression on style self-pollination, a transcriptome-wide comparative analysis of SC and SI tomato unpollinated/pollinated styles was performed using RNA-sequencing (RNA-seq) data.ResultsTranscriptome profiles of 24-h unpollination (UP) and self-pollination (P) styles from SC and SI tomato species were generated using high-throughput next generation sequencing. From the comparison of SC self-pollinated and unpollinated styles, 1341 differentially expressed genes (DEGs) were identified, of which 753 were downregulated and 588 were upregulated. From the comparison of SI self-pollinated and unpollinated styles, 804 DEGs were identified, of which 215 were downregulated and 589 were upregulated. Nine gene ontology (GO) terms were enriched significantly in SC and 78 GO terms were enriched significantly in SI. A total of 105 enriched Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were identified in SC and 80 enriched KEGG pathways were identified in SI, among which “Cysteine and methionine metabolism pathway” and “Plant hormone signal transduction pathway” were significantly enriched in SI.ConclusionsThis study is the first global transcriptome-wide comparative analysis of SC and SI tomato unpollinated/pollinated styles. Advanced bioinformatic analysis of DEGs uncovered the pathways of “Cysteine and methionine metabolism” and “Plant hormone signal transduction”, which are likely to play important roles in the control of pollen tubes growth in SI species.Electronic supplementary materialThe online version of this article (doi:10.1186/s12870-015-0492-7) contains supplementary material, which is available to authorized users.

Highlights

Tomato (Solanum lycopersicum) self-compatibility (SC) is defined as self-pollen tubes that can penetrate their own stigma, elongate in the style and fertilize their own ovules
Some models were proposed for growth behavior of pollen tubes within styles that are related to pollen factors such as F-box protein and pistil factor of RNase [5,6]; the mechanism controlling the growth of pollen tubes remains unclear in tomatoes
We identified two ethylene receptors, LeETR6 (Solyc 06g053710) and tETR (Solyc09g089610), which were significantly upregulated in the SI self-pollination (SIP) vs. SI unpollination (SIUP) comparison, both of which mapped to the plant hormone signal transduction Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway

Summary

Introduction

Tomato (Solanum lycopersicum) self-compatibility (SC) is defined as self-pollen tubes that can penetrate their own stigma, elongate in the style and fertilize their own ovules. Self-incompatibility (SI) is defined as self-pollen tubes that are prevented from developing in the style. The stamen comprises an anther generating pollen grains and a filament supporting the anther. The pistil comprises the stigma, the style and the ovary. Pollination is a process of pollen-pistil interaction during which pollen adheres, hydrates, and germinates on the stigma, the Tomatoes (Solanum lycopersicum) are one of the most important vegetable crops in the world, and possess. Color-fruited species such as Solanum lycopersicum, S. pimpinellifolium and S. neorickii are SC species, while some green-fruit species, such as S. habrochaites and S. chilense, are SI species [4]. The growth of pollen tubes within styles differs between SI and SC species. Some models were proposed for growth behavior of pollen tubes within styles that are related to pollen factors such as F-box protein and pistil factor of RNase [5,6]; the mechanism controlling the growth of pollen tubes remains unclear in tomatoes

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Conclusion