Self-incompatible plants

[George R Stilwell, Jr.]

OK. I know this is off subject, but Nina Lambert sent me a fascinating
article
from the 'Cornell Chronicle' and I just have to tell someone about it.
It seems that 3 researchers have found the gene in Kale pollen that
allows the stigma to
determine if the pollen is from itself or from other Kale plants.

An abstract of the article:

Over a century ago, scientists discovered that some plants don't permit
fertilization by their own pollen.
And for the past quarter century, scientists have known that cellular
communication exists between the
female stigma and the male gamete, or pollen, it receives. But no one
knew how the stigma could tell the difference between the plant's own
pollen and that from other plants.

Now, Cornell researchers J. Nasrallah, M. Nasrallah, and C. Schopfer have
published a paper in 'Science'
that describes how this is accomplished. It seems that a gene located at
the so-called S locus, the genomic region known to control the
recognition phenomenon, and named "S locus cysteine-rich protein", or
SCR, is the male determinant of the plants reproduction process. It is
the long-sought-after key to why the stigma will reject the plant's own
pollen but accept that from other Kale plants. It is expressed in the
plants anther which produces and genetically codes the pollen.

This mechanism against self-pollination is found in Kale plants and other
members of the Crusifer family.
The mating, or self-incompatibility, type is determined by that single
address on the plants genome. To
prove that the SCR gene is the determinant, Nasrallah lab transferred the
gene from one Kale plant to
another Kale plant. The pollen of latter would normally be accepted by
the former plant, but with the
gene replaced, it is rejected. There's even a picture of the act of
pollen acceptance taken in UV light
and allowing the acceptance/rejection to be viewed.

Should you find this new understanding so compelling that you need more
information,
the 'Science' article is titled "The Male Determinant of
Self-Incompatibility in Brassica". Unfortunately,
the vol. and Pages are not given in the Chronicle article. Perhaps they
thought we'd be
better off out digging in the garden.

Ray
<GRSJr at Juno.com>

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