Sulphur responsiveness of the Chlamydomonas reinhardtii LHCBM9 promoter

Abstract

A 44-base-pair region in the Chlamydomonas reinhardtii LHCBM9 promoter is essential for sulphur responsiveness. The photosynthetic light-harvesting complex (LHC) proteins play essential roles both in light capture, the first step of photosynthesis, and in photoprotective mechanisms. In contrast to the other LHC proteins and the majority of photosynthesis proteins, the Chlamydomonas reinhardtii photosystem II-associated LHC protein, LHCBM9, was recently reported to be up-regulated under sulphur deprivation conditions, which also induce hydrogen production. Here, we examined the sulphur responsiveness of the LHCBM9 gene at the transcriptional level, through promoter deletion analysis. The LHCBM9 promoter was found to be responsive to sulphur deprivation, with a 44-base-pair region between nucleotide positions -136 and -180 relative to the translation start site identified as essential for this response. Anaerobiosis was found to enhance promoter activity under sulphur deprivation conditions, however, alone was unable to induce promoter activity. The study of LHCBM9 is of biological and biotechnological importance, as its expression is linked to photobiological hydrogen production, theoretically the most efficient process for biofuel production, while the simplicity of using an S-deprivation trigger enables the development of a novel C. reinhardtii-inducible promoter system based on LHCBM9.

A Blue Light-Responsive Strong Synthetic Promoter Based on Rational Design in Chlamydomonas reinhardtii

“…These promoters can be triggered by controlled environmental cues and deliver a rapid, dose-dependent response [11]. The addition of chemicals [40], depletion of nutrients [41], application of heat shock [13], and irradiation of high light [30] and green light [42] are some examples of induction systems. Among them, light is advantageous over others as it avoids chemical toxicity and nutrition scarcity, is instantaneously effective compared to heat shock, and its use of a specific light spectrum as an inducer is particularly attractive because it ensures a more specific control on the gene expression.…”

Biocircuits in plants and eukaryotic algae

“…Inducible and repressible promoters were also available. Among them, it is worth listing: the metal-responsive CYC6 promoter, induced by nickel and repressed by copper ions (Ferrante et al, 2008); the METE promoter, repressible by vitamin B12 (Helliwell et al, 2014); the sulfur starvation-induced promoter of LHCBM9 (Sawyer et al, 2015); an light-inducible promoter from Dunaliella sp. (Baek et al, 2016); the salt-inducible promoter from C.reinhardtii GPDH3 gene (Beltran-Aguilar et al, 2019); an alcohol-inducible promoter from A. nidulans (Lee et al, 2018); and the promoters inducible by digoxin and β-estradiol, that were previously effective for other eukaryotic organisms and adapted for P. tricornutum (Kassaw et al, 2022).…”

The Synthetic Biology Toolkit for Photosynthetic Microorganisms

“…Numerous genetic parts are available for the control of gene expression including diverse inducible, repressible and constitutive promoters and multiple 39untranslated region (3'UTR)/terminators (Ohresser et al, 1997;Schroda et al, 2000;Fischer and Rochaix, 2001;Ferrante et al, 2008;Helliwell et al, 2014;Sawyer et al, 2015;Baek et al, 2016;Lee et al, 2018;Watanabe et al, 2018;Beltran-Aguilar et al, 2019). The promoters are detailed in Box 2.…”

“…Three inducible promoters are known: the CYC6 promoter induced by nickel and also repressed by copper (Ferrante et al, 2008), the sulfur starvationinduced promoter of LHCBM9 (Sawyer et al, 2015), and the Dunaliella LIP promoter that is light-inducible and functional in Chlamydomonas (Baek et al, 2016). .…”