GSE109672
The coupling of transcriptome and proteome adaptation during development and heat stress response of tomato pollen
Pollen development is central for plant reproduction and is assisted by changes of the transcriptome and the proteome. At the same time, pollen is largely heat sensitive, particularly at early developmental stages. To define the changes during development and the response of different stages to elevated temperatures we investigated the transcriptome and proteome of pollen at tetrad, post-meiotic and mature stage before and after application of elevated temperatures. We used Solanum lycopersicum as an economically important crop. We demonstrate that the number of transcripts declines from tetrad to mature stage, while the protein content shows the opposite trend. Comparison of the transcriptome and proteome led to the discovery of two translational modes assigned as direct translation – transcripts increased in a specific pollen stage lead to increased translation in the same stage – and delayed translation – transcripts are produced for translation in later stages. The response to elevated temperatures is with ~5% of all genes being upregulated comparable to general plant behavior. The alteration at proteome level marked the mature pollen as least responsive and the post-meiotic stages as most responsive with altered levels of 40% of the identified proteins. For a subset of the genes with direct translation we observed a downregulation of protein levels after heat stress, whereas some of the genes with delayed translation showed a shift from delayed to direct translation when heat stress is applied. Further, Hsps, proteasome subunits, ribosomal proteins as well as eukaryotic initiation factors are the most drastically affected groups. On the example of Hsps we document that the response at transcriptome and proteome levels in e.g. the post-meiotic and mature stage does not correlate. Moreover, while all stages respond to heat stress with regulation of transcript abundance of Hsps in a comparable manner, changes at proteome level are distinct. Thus, we demonstrate that the difference in heat stress response in different stages of pollen development is rather manifested by significant changes of protein than transcript abundance. ------------------------------------------------------- Solanaceae Pollen Thermotolerance Initial Training Network (SPOT-ITN) Consortium Overall design: 12 samples (3 developmental stages under 2 conditions (control and heat stress) with 2 biological replicates)