AUTHOR=Miyazawa Ken , Yamashita Takaaki , Takeuchi Ayumu , Kamachi Yuka , Yoshimi Akira , Tashiro Yuto , Koizumi Ami , Ogata Makoto , Yano Shigekazu , Kasahara Shin , Sano Motoaki , Yamagata Youhei , Nakajima Tasuku , Abe Keietsu 

TITLE=A Glycosylphosphatidylinositol-Anchored α-Amylase Encoded by amyD Contributes to a Decrease in the Molecular Mass of Cell Wall α-1,3-Glucan in Aspergillus nidulans

JOURNAL=Frontiers in Fungal Biology

VOLUME=2

YEAR=2022

URL=https://www.frontiersin.org/journals/fungal-biology/articles/10.3389/ffunb.2021.821946

DOI=10.3389/ffunb.2021.821946

ISSN=2673-6128

ABSTRACT=<p>α-1,3-Glucan is one of the main polysaccharides in the cell wall of <italic>Aspergillus nidulans</italic>. We previously revealed that it plays a role in hyphal aggregation in liquid culture, and that its molecular mass (MM) in an <italic>agsA</italic>-overexpressing (<italic>agsA</italic><sup><italic>OE</italic></sup>) strain was larger than that in an <italic>agsB</italic>-overexpressing (<italic>agsB</italic><sup><italic>OE</italic></sup>) strain. The mechanism that regulates its MM is poorly understood. Although the gene <italic>amyD</italic>, which encodes glycosylphosphatidylinositol (GPI)-anchored α-amylase (AmyD), is involved in the biosynthesis of α-1,3-glucan in <italic>A</italic>. <italic>nidulans</italic>, how it regulates this biosynthesis remains unclear. Here we constructed strains with disrupted <italic>amyD</italic> (Δ<italic>amyD</italic>) or overexpressed <italic>amyD</italic> (<italic>amyD</italic><sup><italic>OE</italic></sup>) in the genetic background of the ABPU1 (wild-type), <italic>agsA</italic><sup><italic>OE</italic></sup>, or <italic>agsB</italic><sup><italic>OE</italic></sup> strain, and characterized the chemical structure of α-1,3-glucans in the cell wall of each strain, focusing on their MM. The MM of α-1,3-glucan from the <italic>agsB</italic><sup><italic>OE</italic></sup><italic>amyD</italic><sup><italic>OE</italic></sup> strain was smaller than that in the parental <italic>agsB</italic><sup><italic>OE</italic></sup> strain. In addition, the MM of α-1,3-glucan from the <italic>agsA</italic><sup><italic>OE</italic></sup> Δ<italic>amyD</italic> strain was greater than that in the <italic>agsA</italic><sup><italic>OE</italic></sup> strain. These results suggest that AmyD is involved in decreasing the MM of α-1,3-glucan. We also found that the C-terminal GPI-anchoring region is important for these functions.</p>