Manganese homeostasis modulates glucan and chitin unmasking in Candida albicans

In our previous work, we generated a mutant of the Mn NRAMP transporter, smf12, to investigate the impact of Mn scarcity on the biology of C. albicans. We found that inactivation of SMF12 resulted in attenuated virulence, increased sensitivity to azoles, and activation of the unfolded protein response (UPR). To investigate further cellular processes affected in smf12, we carried out RNA-seq profiling under manganese (Mn) starvation. The transcriptional profile of smf12 growing in the Mn-free SC medium (SC-Mn) was compared to that of the WT strain growing under similar conditions. Upregulated transcripts in smf12 were mainly enriched in processes related to the synthesis and the processing of the three core polysaccharides of the fungal cell wall namely chitin (CHS2, 7, CDA2, CHT4), glucan (KRE1, 9, UTR2, PNG2) and phosphomannan (MNN1, 15, 41, 42, 43, 45, 47, BMT3, 4, 6, 7, KTR4, DFG5, FAV3). Transcripts related to cell wall signaling proteins and transcriptional control including the Cek1 MAP kinase, the histidine kinase Chk1 and the transcription factor Crz1 were also upregulated. This transcriptional signature is reminiscent of a situation in which the cell wall is undergoing remodeling in response to a specific perturbation. In this study, we identified transcripts that were modulated in the Candida albicans mutant of the manganese NRAMP transporter, smf12. The transcriptional profile of smf12 grown in Mn-free SC (SC-Mn) or Mn-supplemented medium (SC+Mn) was compared to that of the wild-type (WT) strain grown under similar conditions