Morphogenesis in Isolated Microspore Cultures of Brassica juncea

Abstract

Androgenesis is a phenomenon in which microspores are made to bypass the sexual pathway and follow the sporophytic mode of development to generate new plants without the intervention of fertilization under specialized in vitro conditions. Microspore culture provides an ideal system, with a large, relatively uniform population of haploid cells, for use in mutant selection, genetic transformation and in studies on the molecular mechanism of induction of androgenesis and embryogenesis. This paper involves a study on establishing a reproducible and efficient protocol for microspore embryogenesis in various varieties of Brassica juncea. The genotype had a pronounced effect on androgenic response in microspore cultures. The cultivar Rajat exhibited the most response, producing around 3500 embryos/100 buds. The microspores of B. juncea cv. PR-45 from ed plants maintained at a day/night temperature of 10°C/5°C form embryos with suspensors with varied morphology. The microspore embryos germinated to produce plants with frequencies. These plants exhibited 52% survival and 74% fertility.Abbreviations: ABA -abscisic acid; DAPI -4,6-diamidino-2-phenylindole; DMRT -duncanÕs multiple range test; GA 3 -giberrelic acid

Harnessing mutant donor plants for microspore culture in Indian mustard [Brassica juncea (L.) Czern and Coss]

“…Nevertheless, media manipulations and use of appropriate growth regulators, in future investigations may improve recovery of plantlets and as demonstrated by our earlier work, fine-tuning the colchicines exposure duration (Prem et al 2008b), may lead to higher recovery of mutant DH plants. The genotypic differences observed for germination of mutant control embryos is similar to earlier reports from nonmutant embryos of B. juncea and B. napus (Prem et al 2008b;Chanana et al 2005;Palmer et al 1996).…”

Doubled haploid production in rocket (Eruca sativa Mill.) through isolated microspore culture

“…Embryos obtained from media containing AC gave a similar response without desiccation or with a short desiccation treatment. In contrast to other Brassica (Rudolf et al 1999;Chanana et al 2005) all concentrations of ABA treatments gave negative results. It seems likely that rocket embryos do not require the same level of induced dormancy and do not therefore react in the same way to simulated seed-like conditions.…”

Activated charcoal induced high frequency microspore embryogenesis and efficient doubled haploid production in Brassica juncea

“…Although Chanana et al (2005) reported microspore isolation from 2.7 to 3.5 mm buds in four bud sizes (increments of 2 mm), their results do not reveal the extent of variation for microspore embryogenesis from individual bud sizes. Genotype specificity for bud size selection as reported in the present study has also been reported in B. napus (Telmer et al 1992;Chuong et al 1988;Gland et al 1988).…”

“…Both the frequency of microspore embryogenesis from multiple genotypes (Hiramatsu et al 1995;Lionneton et al 2001) and their subsequent diploidization were low for application in breeding programs. Recent reports (Prem et al 2005;Chanana et al 2005, Agarwal et al 2006) elaborate the effects of various exogenous and endogenous factors on B. juncea microspore embryogenesis, establishing that efficiency of microspore totipotency is particularly dependent on the donor plant genotype, selection of flower buds containing totipotent late uninucleate microspores and the culture medium. The present investigation describes the effect of activated charcoal (AC) for enhanced microspore embryo production and describes methodology for efficient regeneration and diploidization to produce DH B. juncea plants.…”