Investigating Triticeae anther gene promoter activity in transgenic Brachypodium distachyon
Citation
Zaidi, M.A., O’Leary, S.J.B., Wu, S., Chabot, D., Gleddie, S., Laroche, A., Eudes, F., Robert, L.S. (2017). Investigating Triticeae anther gene promoter activity in transgenic Brachypodium distachyon. Planta, [online] 245(2), 385-396. http://dx.doi.org/10.1007/s00425-016-2612-5
Plain language summary
Crop reproduction provides the seeds that we consume or use to plant the next crop. Pollen grains produced in specialized organs called anthers carry the sperm cells required for the sexual reproduction of most major crops in Canada. Only a portion of a plant’s genes are expressed within the anther and this tissue-specific expression is regulated by associated sequences called promoters. In other words, a promoter determines where and when a gene will be expressed. We understand very little about how anther promoter sequences work. This is especially true for cereals where testing promoters is difficult. In this report, we show that Brachypodium distachyon (Purple false brome) could be used as an efficient model species to study cereal anther promoters to better understand how they work.
Abstract
Main conclusion: In this report, we demonstrate thatBrachypodium distachyoncould serve as a relatively high throughputin plantafunctional assay system for Triticeae anther-specific gene promoters. There remains a vast gap in our knowledge of the promoter cis-acting elements responsible for the transcriptional regulation of Triticeae anther-specific genes. In an attempt to identify conserved cis-elements, 14 pollen-specific and 8 tapetum-specific Triticeae putative promoter sequences were analyzed using different promoter sequence analysis tools. Several cis-elements were found to be enriched in these sequences and their possible role in gene expression regulation in the anther is discussed. Despite the fact that potential cis-acting elements can be identified within putative promoter sequence datasets, determining whether particular promoter sequences can in fact direct proper tissue-specific and developmental gene expression still needs to be confirmed via functional assays preferably performed in closely related plants. Transgenic functional assays with Triticeae species remain challenging and Brachypodium distachyon may represent a suitable alternative. The promoters of the triticale pollen-specific genes group 3 pollen allergen (PAL3) and group 4 pollen allergen (PAL4), as well as the tapetum-specific genes chalcone synthase-like 1 (CHSL1), from wheat and cysteine-rich protein 1 (CRP1) from triticale were fused to the green fluorescent protein gene (GFP) and analyzed in transgenic Brachypodium. This report demonstrates that this model species could serve to accelerate the functional analysis of Triticeae anther-specific gene promoters.