Biology subjects

Essemine, J.

Publications and source records attributed to Essemine, J..

3 recordsLinked to original sources

bioRxiv2023

PIF4 promotes water use efficiency during fluctuating light and drought resistance in rice

Molecular mechanism of intrinsic water use efficiency (iWUE) during fluctuating light (FL) was rarely understood. In this study, we investigated five parameters of iWUE under FL in 200 Minicore rice accessions. Among them, a novel trait, WUEFL (averaged iWUE during FL) has highest SNP heritability in these parameters. GWAS identifies six candidate genes, and PIF4 is highly expressed in high iWUEFL rice subgroup. Nine SNPs were significantly associated with iWUEFL, and v3 SNP located at -1,075 bp of PIF4 promoter shows highest sensitives to light. Deletion of v3 in a rice cultivar, WYG7 (PIF4v3m) leads to [~]20% reduction in iWUEFL, and overexpressing PIF4 causes 25% increase in iWUEFL under DS. There are 85% reduction in adenosine 3,5-diphosphate (PAP) amounts together with 73% increase in SAL1 gene abundance in PIF4v3m than WYG7. PIF4 transcriptionally repress and activate SAL1 and NHX1, respectively, through binding to G-box motifs of the two genes, which leads to 16% reduction and 5% increase in iWUEFL in co-overexpression rice lines of PIF4-SAL1 and PIF4-NHX1, respectively, relative to PIF4-OE under DS. We proposed that PIF4 promotes iWUEFL and stomatal adjustment via targeting the G-box motif of SAL1 and NHX1 genes during FL, eventually facilitating to drought resistance.

plant biology↗

bioRxiv2020

A non-enzymatic acetylation of lysine residues adversely affects the Rubisco activase protein stability

The post-translational modifications of non-histone (PTMs) proteins functions are crucial for the plant adaption to the changing environment. The Rubisco activase (RCA) plays a key role in the CO2 fixation through the Rubisco activation process. We reported that the RCA from tobacco leaf could be acetylated at several lysine residues including K126 and K164. The acetylation level changes under different light conditions (night and day) as well as under heat stress (45 {degrees}C). We further showed that the RCA can be non-enzymatically acetylated in vitro, especially by the acetyl-CoA (Ac-CoA) through direct interaction between them. Our results of the in vitro assay with deuterium labeled Ac-CoA (D2-Ac-CoA) show that the two conserved RCA lysine residues (K126 and K164) were acetylated by Ac-CoA, entraining a dramatic decline in its ATPase activity and a slight effect on the Rubisco activation process. Furthermore, we revealed that the higher RCA acetylation level induced its faster degradation in the chloroplast, which was not a direct consequence of ubiquitination. Eventually, our findings unraveled a new prominent role for the protein acetylation in modulating the RCA stability, which could certainly regulate the carbon assimilation efficiency towards a different energy status of the plants.

plant biology↗

bioRxiv2020

Evolution of co-regulatory network of C4 metabolic genes and TFs in the genus Flaveria: go anear or away in the intermediate species?

C4 photosynthesis evolved from the ancestral C3 photosynthesis by recruiting pre-existing genes to fulfill new functions. The enzymes and transporters required for the C4 photosynthesis have been intensively studied; however, the transcription factors (TFs) regulating these C4 metabolic genes are not well understood. In particular, how the TF regulatory network of C4 metabolic genes was rewired during the evolution is unclear. Here, we constructed TFs co-regulatory networks for core C4 metabolic genes (C4GRN) for four evolutionarily closely related species from the genus Flaveria, which represent four different evolutionary stages of the C4 photosynthesis, namely, C3, type I C3-C4, type II C3-C4 and C4. Our results show that more than half of the co-regulations of TFs and C4 core metabolic genes were species specific. The counterparts of C4 genes in C3 species were already co-regulated with the photosynthesis-related genes; whereas the required TFs for the C4 photosynthesis were recruited later. The type I C3-C4 species recruited 40% of C4 required TFs which co-regulated all core C4 metabolic genes but PEPC; nevertheless, the type II C3-C4 species took on a high divergent C4GRN with C4 species itself. In C4 species, PEPC and PPDK-RP possessed much more co-regulated TFs than other C4 metabolic genes. This study provides for the first time the TFs profiles of the C4 metabolic genes in species with different photosynthetic types and reveal the dynamic of C4 genes-TFs co-regulations along the evolutionary process, providing thereby new insights into the evolution of C4 photosynthesis.

evolutionary biology↗