Growth of the white rust fungus Albugo candida in callus tissue of Brassica juncea

Growth ofAlbugo Candidain leaf callus cultures ofBrassica rapa

“…Besides a slight delay in the formation of haustoria in the dark, there was no apparent effect of the light or dark incubation conditions. Lahiri and Bhowmik (1993) observed haustorium formation under constant, low (70 uEnrV), fluorescent illumination. An effect of the photoperiod on the formation of haustoria has been demonstrated in barley coleoptiles and leaves infected with Erysiphe pisi (Yamaoka et al 1993) and E. graminis hordei (Edwards 1993) and in Sphaerotheca fuligineainfected cucumber leaves (Arimoto & Homma 1992).…”

“…There is a possibility that the growth regulators and sucrose used in the culture medium for host callogenesis played a role in haustorial production. Lahiri & Bhowmik (1993) also reported that A. Candida race 2 produced haustoria in callus tissues of its host, B. juncea, when cultured on a similar medium (MS medium supplemented with 2.0 mg L" 1 BAP). In other, unrelated, fungi, haustorial production is stimulated by plant growth regulators (abscisic acid and gibberellic acid) (Li & Heath 1990) and by carbohydrates (Heath 1990).…”

“…Temperatures of 25°C and above favour the production of oospores over that of zoosporangia in A. Candida (Verma et al 1983, Goyal et al 1996 and in A. occidentalis (Raabe & Pound 1952a). Incubation temperatures of 25 and 30°C also favoured the formation of oospores in A. candidainfected B. juncea callus tissues (Lahiri & Bhowmik 1993), although the origin of the oospores was not clear; the hypertrophied inflorescences used as expiants invariably contained abundant oospores.…”

“…and Coss. (Lahiri & Bhowmik 1993), and A. Candida (unidentified race) and B. rapa L. (Goyal et al 1995). The authors observed zoosporangia and oospores in callus tissues derived from hypertrophied stems (Singh 1966, Goyal et al 1995 or hypertrophied peduncles and thickened terminal leaves (Lahiri & Bhowmik 1993), but the origin of both sexual and asexual spores was not determined.…”

“…(Lahiri & Bhowmik 1993), and A. Candida (unidentified race) and B. rapa L. (Goyal et al 1995). The authors observed zoosporangia and oospores in callus tissues derived from hypertrophied stems (Singh 1966, Goyal et al 1995 or hypertrophied peduncles and thickened terminal leaves (Lahiri & Bhowmik 1993), but the origin of both sexual and asexual spores was not determined. The objectives of the present study were to establish A. Candida race 7V (Petrie 1994) in leaf callus tissues of its host, B. rapa L.; to study the temporal development of the fungus in dual culture; and to assess the pathogenicity of in vitro-produced zoosporangia and oospores.…”