Natural GMOs Part 188. Red Queen Redux. Jungle Chemical Warfare Battle for Survival May Yield the Rain Forest’s Diversity

Image, Tenial, Copyright expired.

Carl Zimmer explains the jungle chemical warfare story:

...Plants are not helpless victims, however. They have evolved a staggering variety of defenses. Some grow cups of nectar on their leaves to attract sugar-hungry ants, which also attack insects feeding on the leaves. Some plants defend themselves by sprouting hairs. “To us they seem soft and fuzzy,” Dr. Coley said, “but to a small caterpillar with a soft belly, they can be more like meat hooks.”
The most impressive defenses in tropical plants are invisible, however. A plant may pack each of its leaves with hundreds of kinds of insect poisons. Those toxins can make up half the dry weight of a tropical plant leaf.
As farmers know all too well, insects can evolve resistance to pesticides. A similar evolution plays out in tropical forests, where insects can disarm many of the chemicals that plants use against them.
Of course, plants in temperate regions face attacks from insects, too. But Dr. Coley and Dr. Kursar argue that those plants are more adapted to the bigger threats they face, from the bitter cold of winter and other environmental challenges. In the tropics, plants enjoy a balmy climate year-round. While the physical environment poses less of a threat to tropical plants, it makes insects a bigger danger. They can grow faster in the warm, moist climate; without killing frosts, they can produce more generations each year.
The tropics have thus become host to an arms race. Each species of plant is evolving defenses against its enemies, which evolve counterdefenses in turn. This arms race would explain why tropical plants have become so loaded with toxic compounds...

More @ Battle for Survival May Yield the Rain Forest’s Diversity - NYTimes.com:

About On Tropical Forests and Their Pests
Phyllis D. Coley, Thomas A. Kursar
Science 3 January 2014: Vol. 343 no. 6166 pp. 35-36 DOI: 10.1126/science.1248110

Key Quote

"Evidence from several lineages of tropical trees and shrubs shows that closely related species have diverged in defenses while differing little in nondefense traits (9–12). This supports the Red Queen hypothesis (13), which states that antagonistic interactions between hosts and their pests lead to natural selection for beneficial adaptations and counter-adaptations in both groups. Because herbivores are continually evolving counter-adaptations to plant defenses, plant defensive traits should evolve faster than adaptations to a more static abiotic environment."

References and Notes

1. S. J. Wright, Oecologia 130, 1 (2002).
2. C. Baralotoet al., J. Ecol. 100, 690 (2012).
3. D. T. Palowet al., Funct. Ecol. 26, 1144 (2012).
4. B. E. Sedioet al., J. Ecol. 100, 1183 (2012).
5. X. Liuet al., Funct. Ecol. 27, 264 (2013).
6. E. G. Leighet al., Biotropica 36, 447 (2004).
7. D. W. Schemskeet al., Annu. Rev. Ecol. Evol. Syst. 40, 245 (2009).
8. J. X. Becerra, Proc. Natl. Acad. Sci. U.S.A. 104, 7483 (2007). The impact of herbivore–plant coevolution on plant community structure
9. T. A. Kursaret al., Proc. Natl. Acad. Sci. U.S.A. 106, 18073 (2009). The evolution of antiherbivore defenses and their contribution to species coexistence in the tropical tree genus Inga
10. B. E. Sedio, thesis, University of Michigan (2013)
11.  J. X. Becerra, K. Noge, D. L. Venable, Proc. Natl. Acad. Sci. U.S.A. 106, 18062 (2009). Macroevolutionary chemical escalation in an ancient plant–herbivore arms race
12. P. V. A. Fineet al., Ecology 94, 1764 (2013).
13. L. Van Valen, Evol. Theory 1, 1 (1973).
14. M. R. Servedioet al., Trends Ecol. Evol. 26, 389 (2011).

See also previous GMO Pundit posts: 

• Natural GMOs Part 19. The Evolutionary Arms Race.
• Natural GMOs Part 20. The Red Queen. 
• Natural GMOs Part 170. The Red Queen was right: We have to run to keep in place

Genetic discovery points the way to much bigger yields in tomato, other flowering food plants

A mutation in the hormone that controls flowering
postpones when a plant stops producing flowers,
 yielding many more fruits. Credit: Cold Spring Harbor Laboratory

Phys.org/CSHL December 26th, 2013 in Biology / Biotechnology

Every gardener knows the look of a ripe tomato. That bright red color, that warm earthy smell, and the sweet juicy flavor are hard to resist. But commercial tomato plants have a very different look from the backyard garden variety, which can grow endlessly under the right conditions to become tall and lanky. Tomatoes that will be canned for sauces and juice are harvested from plants that stop growing earlier than classic tomato varieties, and are therefore more like bushes. While the architecture of these compact bushy plants allows mechanical harvesters to reap the crop, the early end of growth means that each plant produces fewer fruits than their home garden cousins.
But what if commercial tomato growers could coax plants into producing more fruit without sacrificing that unique and necessary bushy plant shape? Today, CSHL researchers announced that they have determined a way to accomplish this. Their research has revealed one genetic mechanism for hybrid vigor, a property of plant breeding that has been exploited to boost yield since the early 20th century. Teasing out the hidden subtleties of a type of hybrid vigor involving just one gene has provided the scientists with means to tweak the length of time that bushy tomato varieties can produce flowers. In these plants, longer flowering time substantially raises fruit yield.
First identified at CSHL by George Shull in 1908, hybrid vigor – or heterosis, as biologists call it – involves interbreeding genetically distinct plants to generate offspring more robust than either inbred parent. It has been used for decades to improve agricultural productivity, but scientists have long debated how and why it works.
In his previous work, CSHL Associate Professor Zach Lippman and Israeli colleagues identified a rare example of hybrid vigor involving a genetic defect in the gene that makes florigen, a hormone that controls the process of flowering and flower production. The mutation dramatically increases tomato yields in bush tomatoes, and Lippman and his team, led by postdoctoral researcher Ke Jiang, set out to understand the mechanism behind this remarkable result.
They found that bushy plants with a mutation in one of the two copies of the florigen gene, producing half as much florigen as plants without the mutation do, postpone the moment when they stop producing flowers. This, in turn, leads to many more fruits overall. "This is because," Lippman explains, "bushy tomato varieties are highly sensitive to the amount, or dosage, of the florigen hormone, which alters plant architecture – that is, how many flowers can form before growth ends. These discoveries lead to an exciting prediction: that it may be possible to tweak florigen levels to increase yields even further."
Lippman's team also studied florigen mutants in another plant, the crucifer weed known as Arabidopsis that is a cousin of crops like broccoli and cauliflower. Although they did not see the same increase in yield, they did observe similar changes in plant architecture because of florigen dosage sensitivities. These results suggest that it may be possible to manipulate florigen in a wide variety of flowering species to increase yields.

More information: "Tomato Yield Heterosis is Triggered by a Dosage Sensitivity of the Florigen Pathway that Fine-Tunes Shoot Architecture" appears online in PLOS Genetics on December 26, 2013. The authors are: Ke Jiang, Katie Liberatore, Soon Ju Park, John Alvarez, and Zach Lippman. www.plosgenetics.org/doi/pgen.1004043

Provided by Cold Spring Harbor Laboratory
"Genetic discovery points the way to much bigger yields in tomato, other flowering food plants." December 26th, 2013.

@ Genetic discovery points the way to much bigger yields in tomato, other flowering food plants: