Biological complexity: the brain helps burn fat (Introduction)

by David Turell , Wednesday, February 08, 2017, 16:06 (2845 days ago) @ David Turell

Plans and fungi exchange genetic elements in their battle:

http://www.the-scientist.com/?articles.view/articleNo/48073/title/RNA-Interference-Betw...

"Plants and fungi can use conserved RNA interference machinery to regulate each other’s gene expression—and scientists think they can make use of this phenomenon to create a new generation of pesticides.

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"Noncoding RNAs are well known for their ability to control gene expression in cells. And as scientists have demonstrated repeatedly, protein production can be affected not just by RNAs made in the same individual, but by RNAs from altogether different organisms. In recent years, researchers have taken advantage of the ability to traffic RNA between distantly related taxa to selectively inhibit the expression of genes in fungi important for their growth, an approach they say might lead to the development of disease-resistant crops. Scientists have also shown in the lab that this cross-kingdom RNA transfer can go both ways: fungi are also sending RNA dispatches to their plant hosts, and the covert operation could be aiding their invasion.

"In this conversation between plants and fungi, the organisms rely on a well-worn mechanism of gene-expression regulation that has stood the test of evolutionary time: RNA interference (RNAi). Listening in on the RNA crosstalk between plants and their pathogens could reveal previously unknown facets of basic plant biology, and point the way toward a successful strategy to fend off crop pathogens.

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"RNAi is a widely conserved mechanism used during development, in routine cellular processes, and in response to foreign invaders—especially viruses—entering a cell. The cell produces small RNAs that are then integrated into an aggregation of proteins called the RNA-induced silencing complex (RISC), which targets messenger RNA molecules (mRNAs) containing the small RNA’s complementary sequence. RISC then chops up bound transcripts, thereby tamping down gene expression.

"Over the past decade, scientists have demonstrated RNAi’s ability to protect numerous plants against nonviral pathogenic foes. In 2007, for instance, Monsanto endowed corn with the ability to fend off western corn rootworm by providing the crop with a gene for an RNA that targeted transcripts of an essential gene in the insect. The transgenic plants suffered less damage, presumably because the insects ingested the interfering RNAs and died.1 Around the same time, research groups showed that the approach—called host-induced gene silencing (HIGS)—could also ward off parasitic worms,

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"While the actions of RNAi against viral pathogens within the plant cell have been appreciated for years, it’s unclear whether plants in the wild send RNA mercenaries into fungi and other invading eukaryotic pathogens.

"A few months ago, scientists reported perhaps the first evidence that small-RNA transfer between plants and fungi does indeed occur without the intervention of genetic engineers. Hui-Shan Guo at the State Key Laboratory of Plant Genomics at the Chinese Academy of Sciences in Beijing discovered that cotton plants ramp up the production of certain small RNAs after infection by a fungal pest, Verticillium dahliae. Not only do these plant RNAs tamp down the expression of two essential genes in the pathogen, but mutating the fungus’s genes to be resistant to the RNAi made the pest more virulent. “Our works are the first direct experimental evidence of the mobility of . . . RNA molecules from plants to fungal cells and inducing target gene silencing in fungal cells,” Guo wrote in an email to The Scientist. "

Comment: This article is presented from the viewpoint of using genetics to modify plants, but I am using it to show the complexity of genetic battling in nature. That complexity is an enemy to Darwin's theories, which come from a simplistic understanding of the biology of life.