basA regulates cell wall organization and asexual/sexual sporulation ratio in Aspergillus nidulans

Sphingolipid C4 hydroxylase catalyzes the conversion of dihydrosphingosine to phytosphingosine. In Saccharomycete cerevisiae, Sur2 is essential for sphingolipid C4 hydroxylation activity but not essential for normal growth. Here we demonstrate that the Aspergillus nidulans Sur2 homologue BasA is also required for phytosphingosine biosynthesis but is also essential for viability. We previously reported that a point missense mutation in basA resulted in aberrant cell wall thickening. Here our data suggest that accumulation of dihydrosphingosine is responsible for this phenotype. In addition, two different mutations in basA consistently accelerated the transition from asexual development to sexual development compared to the wild-type strain. The phenotype could be suppressed by exogenous addition of phytosphingosine. Northern analysis suggests that faster sexual development in the basA mutant might be due to higher transcription level of ppoA and steA, genes demonstrated to coordinate asexual and sexual development in A. nidulans. Consistent with these findings, mutations in the ceramide synthase encoding genes barA and lagA also caused faster transition from asexual to sexual development, supporting the involvement of sphingolipid metabolism in fungal development.

Key Words: Aspergillus nidulans, cell wall, development, sphingolipids, sporulation

This article has been cited by other articles:

				C. Simenel, B. Coddeville, M. Delepierre, J.-P. Latge, and T. Fontaine Glycosylinositolphosphoceramides in Aspergillus Fumigatus Glycobiology, January 1, 2008; 18(1): 84 - 96. [Abstract] [Full Text] [PDF]

Online ISS 1091-6490
Copyright 2008 by the Genetics Society of America
phone: 412-268-1812   fax: 412-268-1813   email: genetics-gsa{at}andrew.cmu.edu