A promoter toolbox for tissue-specific expression supporting translational research in cassava (Manihot esculenta)

Wolfgang Zierer; Ravi Bodampalli Anjanappa; Christian Erwin Lamm; Shu-Heng Chang; Wilhelm Gruissem; Uwe Sonnewald

doi:10.3389/fpls.2022.1042379

A promoter toolbox for tissue-specific expression supporting translational research in cassava (Manihot esculenta)

Front Plant Sci. 2022 Dec 20:13:1042379. doi: 10.3389/fpls.2022.1042379. eCollection 2022.

Authors

Wolfgang Zierer¹, Ravi Bodampalli Anjanappa², Christian Erwin Lamm¹, Shu-Heng Chang³, Wilhelm Gruissem^{2

3}, Uwe Sonnewald¹

Affiliations

¹ Biochemistry, Department of Biology, Friedrich-Alexander University Erlangen-Nuremberg, Erlangen, Germany.
² Plant Biotechnology, Department of Biology, Eidgenössische Technische Hochschule (ETH) Zurich, Zurich, Switzerland.
³ Advanced Plant Biotechnology Center, National Chung Hsing University, Taichung, Taiwan.

Abstract

There is an urgent need to stimulate agricultural output in many tropical and subtropical countries of the world to combat hunger and malnutrition. The starchy crop cassava (Manihot esculenta), growing even under sub-optimal conditions, is a key staple food in these regions, providing millions of people with food. Cassava biotechnology is an important technique benefiting agricultural progress, but successful implementation of many biotechnological concepts depends on the availability of the right spatiotemporal expression tools. Yet, well-characterized cassava promoters are scarce in the public domain. In this study, we investigate the promoter activity and tissue specificity of 24 different promoter elements in stably transformed cassava plants. We show that many of the investigated promoters, especially from other species, have surprisingly low activity and/or tissue specificity, but feature several promoter sequences that can drive tissue-specific expression in either autotrophic-, transport- or storage tissues. We especially highlight pAtCAB1, pMePsbR, and pSlRBCS2 as strong and specific source promoters, pAtSUC2, pMeSWEET1-like, and pMeSUS1 as valuable tools for phloem and phloem parenchyma expression, and pStB33, pMeGPT, pStGBSS1, as well as pStPatatin Class I, as strong and specific promoters for heterotrophic storage tissues. We hope that the provided information and sequences prove valuable to the cassava community by contributing to the successful implementation of biotechnological concepts aimed at the improvement of cassava nutritional value and productivity.

Keywords: biotechnology; cassava; parenchyma; phloem; promoter; storage root; tissue; xylem.

Grants and funding

We thank the Bill and Melinda Gates Foundation for funding this research through the grant INV-008053 ‘Metabolic Engineering of Carbon Pathways to Enhance Yield of Root and Tuber Crops’ provided to U.S. We also acknowledge funding of this research by the Advanced Plant Biotechnology Center provided to W.G. as part of The Featured Areas Research Center Program within the framework of the Higher Education Sprout Project by the Ministry of Education in Taiwan. W.G. is a Yushan Scholar of the Ministry of Education in Taiwan.