Promoter and domain structures regulate FLA12 function during Arabidopsis secondary wall development

Yingxuan Ma; Julian Ratcliffe; Antony Bacic; Kim L Johnson

doi:10.3389/fpls.2023.1275983

Promoter and domain structures regulate FLA12 function during Arabidopsis secondary wall development

Front Plant Sci. 2023 Nov 16:14:1275983. doi: 10.3389/fpls.2023.1275983. eCollection 2023.

Authors

Yingxuan Ma^{1

2

3}, Julian Ratcliffe¹, Antony Bacic^{1

4}, Kim L Johnson^{1

4}

Affiliations

¹ La Trobe Institute for Agriculture & Food, Department of Animal, Plant and Soil Science, AgriBio Building, La Trobe University, Bundoora, VIC, Australia.
² State Key Laboratory of Tree Genetics and Breeding, Co-Innovation Center for Sustainable Forestry in Southern China, Nanjing Forestry University, Nanjing, China.
³ Key Laboratory of Forest Genetics and Biotechnology of Ministry of Education, Nanjing Forestry University, Nanjing, China.
⁴ Sino-Australia Plant Cell Wall Research Centre, College of Forestry and Biotechnology, Zhejiang Agriculture and Forestry University, Hangzhou, China.

Abstract

Introduction: Fasciclin-like arabinogalactan-proteins (FLAs) are a family of multi-domain glycoproteins present at the cell surface and walls of plants. Arabidopsis thaliana FLA12 and homologs in cotton, Populus, and flax have been shown to play important functions regulating secondary cell wall (SCW) development. FLA12 has been shown to have distinct roles from the closely related FLA11 that also functions during SCW development. The promoter and domain features of FLA12 that regulate functional specificity have not been well characterized.

Methods: In this study, promoter swap experiments of FLA11 and FLA12 were investigated. Mutation of proposed functional regions within FLA12 were used to investigate the role of post-translational modifications on sub-cellular location and trafficking. Domain swap experiments between FLA11 and FLA12 were performed to identify regions of functional specificity.

Results: Promote swap experiments showed that FLA12 is differentially expressed in both stem and rosette leaves compared to FLA11. Post-translational modifications, in particular addition of the glycosylphosphatidylinositol-anchor (GPI-anchor), were shown to be important for FLA12 location at the plasma membrane (PM)/cell wall interface. Domain swap experiments between FLA11 and FLA12 showed that the C-terminal arabinogalactan (AG) glycan motif acts as a key regulatory region differentiating FLA12 functions from FLA11.

Discussion: Understanding of FLA12 promoter and functional domains has provided new insights into the regulation of SCW development and functional specificity of FLAs for plant growth and development.

Keywords: Arabidopsis thaliana; N-glycosylation; O-glycosylation; fasciclin-like arabinogalactan proteins (FLAs); glycosylphosphatidylinositol-anchor (GPI-anchor); interfascicular fibre (IF); secondary cell wall (SCW); xylem vessel (XV).

Grants and funding

The author(s) declare financial support was received for the research, authorship, and/or publication of this article. KJ was supported by a La Trobe Research Focus Area grant 2000004372. AB and KJ would like to acknowledge a start-up grant from La Trobe University and Zhejiang A&F University for the Sino-Australia Plant Cell Wall Research Centre. YM was supported by a University of Melbourne Scholarship and the Natural Science Foundation of Jiangsu Province (Grants No BK20230391)