Glycosylphosphatidylinositol (GPI) anchoring for cell wall integrity and immune evasion

Southern corn leaf blight, caused by the maize pathogen Cochliobolus heterostrophus, is a major disease affecting maize-growing regions worldwide, posing a serious threat to national food security and public health. Hence, elucidating the pathogenesis of C. heterostrophus is crucial for developing effective novel fungicides.

Glycosylphosphatidylinositol (GPI) anchoring represents a fundamental post-translational modification in eukaryotic cells. In fungi, this modification facilitates diverse biological functions through protein targeting to the cell wall, yet research on its roles in plant pathogenic fungi remains limited. In a new study published in the Journal of Integrative Agriculture, a team of researchers from China elucidated the function of GPI anchoring in the maize fungal pathogen C. heterostrophus.

“Our findings demonstrated widespread accumulation of GPI-anchored proteins in hyphae, appressorium and infection hyphae of C. heterostrophus,” shares corresponding author Xiaolin Chen, a professor at Huazhong Agricultural University, China. “Deletion of ChGPI7, encoding a crucial enzyme in GPI anchor biosynthesis, substantially reduced vegetative growth, conidiation, and virulence through impaired appressorium formation and invasive growth.”

Notably, ΔChgpi7 mutants exhibited marked deficiencies in cell wall integrity, leading to decreased stress resistance. “Both ChGPI7 deletion and hydro fluoric acid (HF) pyridine treatment eliminated cell wall GPI-anchored proteins and exposed chitin, indicating that GPI-anchored proteins shield chitin from host immune recognition,” adds Chen.

Further analysis performed by the team identified 124 predicted GPI-anchored proteins in C. heterostrophus, including the putative cell wall glycoprotein ChFEM1.  

“The deletion of ChFEM1 similarly reduced virulence and compromised infection structures and cell wall integrity,” says lead author Hong Hu. “Additionally, ChGPI7 influenced both the cell wall localization and protein abundance of ChFEM1.”

Taken together, the findings, published in the Journal of Integrative Agriculture, demonstrate that GPI anchoring mediates cell wall integrity and immune evasion during C. heterostrophus infection.

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Contact the author: Correspondence Xiaolin Chen, E-mail: chenxiaolin@mail.hzau.edu.cn

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