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.
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.
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
are produced in sori that supplant the ovaries, rendering infected flowers sterile.
Telia hypophyllous, scattered between veins, 0.1-0.3 mm wide, erumpent, smooth, of numerous teliospores
in compact layer, gelatinous when moist, orange-yellow to reddish orange; teliospores
64-85 x 23-32 gm, oblong to clavate, rounded at apex and narrowing at base, contents oily and refractive, orange-yellow, walls smooth, hyaline, thicker at apex than at sides.
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.