Arbuscular mycorrhizas formed by Asphodelus fistulosus and Glomus coronatum: three-dimensional analysis of plant nuclear shift using laser scanning confocal microscopy

Two main morphological types of arbuscular mycorrhizas (AM) are recognised, the Arum-type and the Paris-type. Most research has focused on the Arum-type, including studies of the influence of colonisation on the plant at the cellular level. Modifications in the size, position and shape of plant nuclei in colonised and uncolonised cells of the Paris-type AM formed by Asphodelus fistulosus L. inoculated with Glomus coronatum Giovannetti were investigated in this study. The plants were grown in nurse pots to achieve near synchronous colonisation. Laser scanning confocal microscopy (LSCM) was used to visualise root material and to quantify plant nuclear shift in three dimensions, which has not been achieved in the past. In each colonised cell containing arbusculate coils there was a quantifiable increase in the distance from the centre of the nucleus to the closest cell wall and in the volume of the plant nucleus. Similar effects occurred in cells with hyphal coils but were not quantifiable because of small numbers. The position and size of the nucleus did not change in uncolonised cells of either inoculated or uninoculated plants. The significance of the results is discussed with respect to the development of Paris-type AM.Timothy R. Cavagnaro, F. Andrew Smith, Peter Kolesik, Sarah M. Ayling, Sally E. Smit