# FgGCV1, a glycine cleavage system T protein, regulates glycine metabolism and sexual reproduction in Fusarium graminearum

## TL;DR

This study shows that a protein called FgGCV1 in the fungus Fusarium graminearum is important for glycine metabolism and sexual reproduction.

## Contribution

The study identifies FgGCV1 as a key regulator of glycine metabolism and sexual reproduction in Fusarium graminearum.

## Key findings

- FgGCV1 is localized in mitochondria and is essential for sexual reproduction in Fusarium graminearum.
- The ΔFgGCV1 mutant's sexual reproduction defect can be restored by adding 5,10-methylenetetrahydrofolate.
- ΔFgGCV1 accumulates glycine and shows increased calcium stress tolerance, with 1,482 differentially expressed genes identified.

## Abstract

Fusarium head blight (FHB), caused by several Fusarium species, among which the most important and widely distributed worldwide is Fusarium graminearum, in the case that the causal agent is F. graminearum, FHB spread is closely linked to the pathogen’s sexual reproduction. The T protein of the glycine cleavage system (GCVT) is a key component of carbon and nitrogen metabolism in organisms, however its biological function in filamentous fungi, particularly F. graminearum, is still unclear. In this study, we characterized two GCVT homologs (FgGCV1 and FgGCV2) to obtain a better understanding of the metabolic processes occurring in F. graminearum. We found that FgGCV1 and FgGCV2 are localized in mitochondria. Deletion of FgGCV2 had no obvious phenotypic alterations, whereas ΔFgGCV1 mutant exhibited severe defects in sexual reproduction. Notably, the sexual reproduction defect in the ΔFgGCV1 mutant was completely restored by exogenous addition of 5,10-methylenetetrahydrofolate (5,10-CH2-THF). Moreover, ΔFgGCV1 accumulated higher intracellular glycine contents and exhibited increased tolerance to calcium stress. Transcriptome analysis identified 1,482 differentially expressed genes (DEGs) in the ΔFgGCV1 mutant, with DEGs enriched in glycine, serine, and threonine metabolism, as well as reproductive and developmental processes. Collectively, our findings demonstrate that FgGCV1 plays a crucial role in regulating glycine metabolism and sexual reproduction in F. graminearum through the glycine cleavage system (GCS) pathway, providing new insights into the molecular mechanisms underlying the pathogen’s metabolic regulation and sexual development.