weather rant/future

Perhaps cold and hot weather might not matter soon for many gardeners...
Bonnie 6+ ETN

March 9, 2003, NYT


A Frog Lends a Hand to Rhododendrons

By HENRY HOMEYER

FOR the past four years, Dr. Mark Brand has been inserting genes derived 
from an African frog into rhododendrons, trying to create a plant with 
extra resistance to the root rot caused by Phytophthora cinnamomi. A common 
soil fungus, Phytophthora does hundreds of thousands of dollars of damage 
to rhododendrons every year.

Dr. Brand is a horticulturist and a director of the plant biotechnology 
facility at the University of Connecticut in Storrs. And he is able to do 
what seems impossible to an old-fashioned gardener like myself: implant 
something he cannot see - a modified frog gene - into something else he 
cannot see, the DNA of a flowering bush.

Creating a transgenic plant is so far beyond what traditional gardeners and 
hybridizers have done it seems, at first, incomprehensible. But Dr. Brand 
was able to make it seem, to use his words, more like baking a cake. Or 
almost.

Genetic modification has stirred protests in Europe, and some 
environmentalists believe it presents risks that outweigh benefits. But 
scientists are unlikely to stop experimenting, and from talking to Dr. 
Brand, I began to see why. The technology offers scientists the chance to 
create their dream plants.

Dr. Brand chose to introduce a frog protein because other scientists had 
already noticed that it worked against other fungi. The challenge was to 
take the gene that creates the protein and fit it into the genetic 
sequences of a rhododendron.

Though university labs are able to create DNA sequences, these days a 
researcher can pick up the phone and have a biotech company send one over 
for about $50. Once Dr. Brand had the frog protein DNA sequence in hand, he 
inserted it into an E. coli bacteria, which let him easily create all the 
DNA he needed.

After determining which bacteria had been successfully married to the new 
gene, Dr. Brand placed them in a rich broth, allowing them to reproduce 
many times over. He was fattening them for slaughter. The unsuspecting 
bacteria were centrifuged and lysed with an enzyme, splitting them open so 
that he could harvest the DNA.

The next step was shooting the DNA into rhododendron cells with the 
potential to develop into complete plants.

Dr. Brand's gene gun is nothing like the six-shooters that boys have been 
known to lug around in second grade. A small plastic and metal box that 
fits easily on the counter, his gene gun is powered by high-pressure helium.

His ammo is gold dust covered with frog DNA. It goes onto a thin piece of 
red mylar that sits on a screen above the tissue sample. A burst of helium 
knocks the gold off the mylar, sending it flying at the speed of sound.

The target is a petri dish with callus cells from a rhododendron leaf. 
Callus cells are the equivalent of stem cells in animal research. Each can 
multiply quickly, developing into an entire plant if given the right 
signals by plant hormones.

If all goes well in the petri dish, a few cells are penetrated by motes of 
gold carrying the specially prepared DNA. Some cells will incorporate the 
DNA into their own gene sequence at this point, copying it into every cell 
of the plants to-be.

EVENTUALLY, after considerable testing to see if the gene is indeed in the 
plants, these test-tube babies grow into ordinary-looking rhododendron 
plants. The ultimate test is to inoculate them with the Phytophthora fungus 
to see if they will develop root rot - or not. Dr. Brand does this by 
contaminating their soil with kernels of ordinary Uncle Ben's rice that 
have been inoculated with Phytophthora, 36 grains per pot. Controls are 
grown, too.

Dr. Brand said other scientists were genetically modifying roses in hopes 
of developing varieties resistant to powdery mildew and black spot. Still 
others imagine a rose with a new perfume, or maybe an unusual hue. (But if 
you are picturing a perfect black rose, don't count on that happening soon; 
roses are difficult to work with, and black is the toughest color to create.)

Easy-to-manipulate petunias and geraniums have been changing colors in labs 
for years. How soon will they, or the new improved rhododendrons, appear at 
the local garden center? Not soon. Testing will take eight years, and more 
time will be needed for government approval of commercial products.

But success seems likely in the end. Dr. Brand is determined to build a 
better rhodie, and the technology is there to do so. He pointed to a row of 
quart-size pots in a temperature- and climate-controlled chamber at his lab 
with the proud look of a new father. The shiny-leaved young rhodies leaved 
looked pest-free to this gardener.

Copyright 2003 <http://www.nytco.com/>The New York Times Company | Privacy 
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