Inoculation for artificial epidemics: Fresh sporidial suspension derived from
Teliospores populations obtained from each one year old sample preliminary considered an isolate, collected from various vicinities was used, and inoculum was prepared according to the method of Bonde et al., (1996).
Germinations of
teliospores were obtained on 1% water agar (WA) supplemented with the antibiotic tetracycline.
Teliospores ellipsoid, rounded at both ends, dark brown, slightly constricted at the septa, 18-21 x 26-32 um; wall 1-1.5 um thick, smooth; germ pore 1 per cell, mostly apical in the distal cell and near the pedicel or at the septum in the proximal cell, hyaline umbos over the germ pores; apex not thickened; pedicel short, hyaline, not persistent, 3-13 um long.
Suwanit, "Effect of temperature and some substrate on
teliospore germination of sugarcane smut and inoculation methods on infection by Ustilago scitaminea," Kasetsart Journal, vol.
Ustilago violacea is also capable of self-fertilization by conjugation between sporidia from the same
teliospore or between adjacent cells of the promycelium (Brefeld, 1883; Harper, 1899; P.
TELIOSPORES 2-celled abundant, sometimes 1-celled, dimorphic, ellipsoid or oblong, golden brown to blackish brown or chestnut, 20-27.5 (-35) x 17.5-20 um (24.4 x 17.7); wall chestnut brown or paler, smooth, 2-3 um thick, not constricted at the septum, spherical at both ends, germ pores 2, upper cell possess apical and lower cell possess near or adjacent to pedicel; papilla hyaline or light brown, 4-6.5 x 6-10 um, pedicel hyaline, deciduous, 10-98.5 x 6.5-9.5 um.
Also, the American specimens contained more one-celled
teliospores than the Asian specimens, which were far more likely to contain two-celled
teliospores.
Smut
teliospores are produced in sori that supplant the ovaries, rendering infected flowers sterile.
Further, it converts the plant's developing seeds into "bunt balls"--encapsulated, powdery, black masses containing over 10 million
teliospores, which are easily dispersed by wind and rain or mechanical harvest and transport.
After disease infection, mycelia grow within the developing rice kernel, eventually consume the endosperm, and produce numerous spherical black
teliospores (Whitney and Frederiksen, 1975).
Infected plants produce flowers with anthers containing only fungal
teliospores, and spores are transmitted from flower to flower by pollinators.