#androgenesis

Plant tissue culture 2

Plants produced via androgenesis are initially:

Plants produced via androgenesis are initially haploid bearing single chromosome set n derived from meiotic reduction of diploid mother cells into microspores. After meiosis each microspore contains recombined haploid genome; when cultured without fertilization embryogenic divisions maintain this n number, so tissues leaves roots show halved DNA content compared to diploid control confirmed by flow cytometry and chromosome counting revealing for example 7 chromosomes in barley haploid versus 14 diploid. Such haploids exhibit reduced vigor smaller organs small stomatal guard cells and complete

Ref: Kasha & Kao 1970 haploid plants; Maluszynski et al., FAO doubled haploid manual.

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Plant tissue culture 2

Gynogenesis differs from androgenesis because it uses:

Gynogenesis differs from androgenesis because it uses female gametophyte components unfertilized ovules ovaries or embryo sacs as explant source rather than anther pollen. In gynogenesis egg cell synergid or antipodal cells within embryo sac are induced to develop sporophytically into haploid embryo without fertilization, typically by culturing unpollinated ovaries or ovules on sucrose enriched medium with auxin cytokinin combination. Female gametophyte origin ensures captured genome is that of maternal parent, contrasting with androgenesis capturing paternal genome from microspores. Gynogenes

Ref: Yang & Zhou Theor Appl Genet gynogenesis; Bohanec 2009 haploid production review.

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Plant tissue culture 2

Androgenesis is commonly achieved by culture of:

Androgenesis is commonly accomplished through culture of anthers or isolated microspores pollen at uninucleate stage, landmark discovery by Guha and Maheshwari 1964 in Datura innoxia demonstrating that anthers could produce haploid embryos on MS medium. Most responsive microspores are at mid uninucleate to early binucleate stage where gametophytic commitment is still reversible; vacuolate microspores have large central vacuole and peripheral nucleus poised for embryogenic switch. Anthers excised from surface sterilized buds given cold pretreatment 4 degrees for several days or heat shock 33 de

Ref: Nitsch & Nitsch 1969 androgenesis; Germaná 2011 anther culture history; NCBI NBK21429.

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Plant tissue culture 2

Androgenesis results in plants genetically identical to:

Androgenesis results in plants whose nuclear genetic constitution is identical to male parent gamete contribution because development originates from male gametophyte microspore. Microspores formed after meiosis in anther tapetum carry recombined haploid genome representing segregation products of diploid male parent heterozygous loci. Under stress pretreatment cold starvation heat and culture conditions gametophytic program that would normally produce mature binucleate pollen with vegetative generative cells is aborted, sporophytic pathway triggered leading to repeated mitotic divisions formi

Ref: Guha & Maheshwari 1964 androgenesis; Touraev et al., Trends Plant Sci microspore embryogenesis.

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Plant Breeding 4

Androgenesis involves culture of:

Androgenesis is male gametophyte-mediated haploid production pathway exploiting totipotency of immature pollen. Anthers containing uninucleate microspores at late uninucleate to early binucleate stage are excised and cultured on nutrient media, or isolated microspores are separated from anthers and cultured in liquid medium under stress. Developmental program of microspore shifts from pollen grain maturation toward sporophytic division, forming embryo-like structures or callus that regenerate haploid plantlets with n chromosomes derived entirely from paternal gametic genotype. Process exploits

Ref: Seguí-Simarro JM. Androgenesis review 2010 J Exp Bot; Maluszynski et al. FAO Haploid protocols – anther culture

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