Fig. 7: Prevalence of chitin and chitosan across Rhizopus and Mucor species.

a 1D ¹³C CP spectra of two Rhizopus and three Mucor species. Key resonance assignments are shown for resolved peaks. The sharp signals of B3 and Ch6 in R. delemar are absent in other species, but the majority of chitin and chitosan signals are retained. Some new chitosan signals are also spotted as marked with asterisks. b Rigid cell wall polysaccharides in R. delemar (orange) and four other fungal species responsible for CAM. Dashed lines show the types-b and d chitosan signals, while dashed circles show the signals of β−1,3-glucan and type-c chitin; these molecules are mostly absent in other species. The major type-a chitosan and type-a and b chitin are preserved in all species, but some lowly populated chitosan forms with slightly modified structures are also noted in mucor species (asterisks). c Estimation of molar percentages of rigid chitin (orange) and chitosan (purple) forms in Rhizopus and Mucor species. All spectra were measured on 800 MHz NMR spectrometers at 290 K. The MAS frequency was 13.5 kHz MAS for apo R. delemar and 15 kHz for nikkomycin-treated R. delemar as well as R. microspores and Mucor samples. d Root mean square deviation (RMSD) heatmap of chemical shifts between model allomorphs with chitin (left) and chitosan (right) identified in Rhizopus and Mucor species. Abbreviations: R. microsporus (RM), M. hiemalis (MH), M. lusitanicus (ML), M. circinelloides (MC), and two R. delemar samples without (apo) and with (nikko) treatment by nikkomycin Z. Source data are provided as a Source Data file.