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Calcium homeostasis is required for contact‐dependent helical and sinusoidal tip growth in Candida albicans hyphae
Author(s) -
Brand Alexandra,
Lee Keunsook,
Veses Veronica,
Gow Neil A. R.
Publication year - 2009
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.2008.06592.x
Subject(s) - hypha , candida albicans , biology , biophysics , extracellular , tip growth , homeostasis , microbiology and biotechnology , calcium , corpus albicans , morphogenesis , cytosol , biochemistry , botany , chemistry , enzyme , pollen , organic chemistry , pollination , pollen tube , gene
Summary Hyphae of the dimorphic fungus, Candida albicans , exhibit directional tip responses when grown in contact with surfaces. On hard surfaces or in liquid media, the trajectory of hyphal growth is typically linear, with tip re‐orientation events limited to encounters with topographical features (thigmotropism). In contrast, when grown on semisolid surfaces, the tips of C. albicans hyphae grow in an oscillatory manner to form regular two‐dimensional sinusoidal curves and three‐dimensional helices. We show that, like thigmotropism, initiation of directional tip oscillation in C. albicans hyphae is severely attenuated when Ca 2+ homeostasis is perturbed. Chelation of extracellular Ca 2+ or deletion of the Ca 2+ transporters that modulate cytosolic [Ca 2+ ] (Mid1, Cch1 or Pmr1) did not affect hyphal length but curve formation was severely reduced in mid1 Δ and cch1 Δ and abolished in pmr1 Δ. Sinusoidal hypha morphology was altered in the mid1 Δ, chs3 Δ and heterozygous pmr1 Δ/ PMR1 strains. Treatments that affect cell wall integrity, changes in surface mannosylation or the provision of additional carbon sources had significant but less pronounced effects on oscillatory growth. The induction of two‐ and three‐dimensional sinusoidal growth in wild‐type C. albicans hyphae is therefore the consequence of mechanisms that involve Ca 2+ influx and signalling rather than gross changes in the cell wall architecture.