Biology subjects

Lyu, M.-j. A.

Publications and source records attributed to Lyu, M.-j. A..

4 recordsLinked to original sources

bioRxiv2023

Enhancing plant photosynthesis through activating cells deficient in photosynthetic apparatus

Much efforts have been devoted to identify options to improve plant photosynthetic capacity. Most of these engineering focuses more on enhancing photosynthetic capacity of the mesophyll cells. In this study, we specifically expressed CYTOKININRESPONSIVE GATA FACTOR 1 (CGA1) in the vascular bundle and bundle sheath cells (ProGLDPA: CGA1) which generally have low photosynthetic capacity. The introduction of CGA1 resulted in increased numbers and sizes of chloroplasts in both bundle sheath and vascular bundle, without noticeable difference in these properties in mesophylls. Additionally, compared with wild type (WT), transgenic lines showed enhanced development of mitochondria and peroxisomes. Leaf photosynthetic rates in these transgenic lines were higher than those in WT, especially under high light. Furthermore, the amount of RuBisCO, Vcmax, Jmax, and the number of starch granules were also significantly increased in the transgenic lines, which led to about 20% increase in biomass. Remarkably, the CO2 compensation point of ProGLDPA: CGA1 decreased compared with WT, resembling the characteristics of proto-Kranz during C4 evolution. All these results indicated that enhancing photosynthetic properties of vascular bundle and bundle sheath cell is an effective approach to improve leaf photosynthesis, and highlighted that utilization of the cell lacking photosynthetic capacity is a promising way to improve plant photosynthesis for greater capacity.

plant biology↗

bioRxiv2022

Born with intronless ERF transcriptional factors: C4 photosynthesis inherits a legacy dating back 450 million years

The genus Flaveria, containing species at different evolutionary stages of the progression from C3 to C4 photosynthesis, is used as a model system to study the evolution of C4 photosynthesis. Here, we report chromosome-scale genome sequences for five Flaveria species, including C3, C4, and intermediate species. Our analyses revealed that both acquiring additional gene copies and recruiting ethylene responsive factor (ERF) cis-regulatory elements (CREs) contributed to the emergence of C4 photosynthesis. ERF transcriptional factors (TFs), especially intronless ERF TFs, were co-opted in dicotyledonous C4 species and monocotyledonous C4 species in parallel. These C4 species co-opted intronless ERF TFs originated from the Late Ordovician mass extinction that occurred [~]450 million years ago in coping with environmental stress. Therefore, this study demonstrated that intronless ERF TFs were acquired during the early evolution of plants and provided the molecular toolbox facilitating multiple subsequent independent evolutions of C4 photosynthesis.

evolutionary biology↗

bioRxiv2020

STOMAGEN-like Regulates Stomatal Generation Causing Increased Water Use Efficiency during C4 Evolution

C4 photosynthesis optimizes plants carbon and water relations, allowing high photosynthetic rate with low stomatal conductance. Stomata have long been believed as a part of C4 syndrome. However, it remains unclear how stomata traits evolved along the path from C3 to C4. Stomatal patterning was examined in Flaveria genus, a model for studying C4 evolution. Comparative, transgenic and semi-in-vitro experiments were used to study molecular basis that underlies stomatal traits along C4 evolution. Novel results: the evolution from C3 to C4 species through intermediate species is accompanied by a stepwise rather than an abrupt change in the stomatal traits. The initial change occurs near Type II and dramatic change occurs at the C4-like species. On the road to C4, stomata become less in number but bigger in size and changes in stomatal density dominates changes in maximum stomatal conductance (gsmax). The reduction of FSTOMAGEN expression underlies altered gsmax between Flaveria species with different photosynthetic pathways and likely occurs in other C4 lineages. Our study provides insight into the pattern, mechanism and role of stomatal evolution along the road towards C4. This work highlights the stomatal traits in the current C4 evolutionary model and the co-evolution of photosynthetic pathway and stomata.

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↗