[Q] Anther culture - Space aliens stole my mitochondria!

[Wayne Parrott]

In article <9506161909.ah07463 at post.demon.co.uk> markradon at etoncomp.demon.co.uk writes:
>From: markradon at etoncomp.demon.co.uk
>Subject: [Q] Anther culture - Space aliens stole my mitochondria!
>Date: 16 Jun 1995 19:14:44 +0100

>I have been studying A-level biology, and techniques such as anther culture have
>been on the syllabus.  However, I have a query which no-one has yet been able to
>solve and I was hoping someone here might be able to throw some light on it.

>When using anther culture, pollen grains are dusted onto the surface of a 
>nutrient medium.  Occasionally, one will germinate into a monoploid plant.  My 
>question is:
>   Where does this plant get its mitochondria from?
>Do pollen grains have mitochondria? If so, how come mitochondrial DNA is always 
>inherited down the maternal line?

>Any one know the answer to this?

>Any response would be received with great interest.

>Mark


Good question.  The same goes for the chloroplasts.

First, in the cases that I am familiar with, the haploid plant (not 
necessarily a monoploid-- if your plant is a polyploid to begin with, what you 
recover from anther culture will have more than one genome in it, so it won't 
be a monoploid!) originates from the microspore or pollen that is still at the 
uninucleate stage-- this is a stage before the mitotic divisions take place 
that lead to the formation of mature pollen, and a complete cell is still 
present.

Secondly, pollen transmission of cytoplasmic organelles in angiosperms is 
probably more common than previously thought.

Here are a couple of references for those interested:

Herberle-Bors E (1985) In vitro haploid formation from pollen: a critical review.
Theor Appl Genet 71:361-374

Reynolds TL (1990) Ultrastructure of pollen embryogenesis. In: Bajaj YPS (Ed) 
Biotechnology in agriculture and forestry, Vol. 12  Haploids in crop 
improvement I (pp 66-82). Springer-Verlag, Berlin Heidelberg

Lee DJ, Blake TK & Smith SE (1988) Biparental inheritance of chloroplast DNA 
and the existence of heteroplasmic cells in alfalfa.  Theor Appl Genet 
76:545-549

Erickson L, Kemble R & Swanson E (1989) The Brassica mitochondrial plasmid can 
be sexually transmitted. Pollen transfer of a cytoplasmic genetic element.  
Mol Gen Genet 218:419-422

Erickson L & Kemble R (1990) Paternal inheritance of mitochondria in rapeseed 
(Brassica napus).  Mol Gen Genet 222:135-139

Dulieu H, Derepas A & Cornu A (1990) Le rôle du pollen dans la transmission 
des chloroplasts et des mitochondries.  Etude d'un cas particulier chez 
Petunia.  Bull Soc bot Fr , Actual bot 137:49-56