Notes

Genetically modified crops have advantages over the weeds

Plants in the wild could be treated with herbicides.

Weedy rice can take on transgenes from genetically modified crops through cross-pollination. Credit: Xiao Yang
A method of genetic modification used extensively to produce crops that are herbicide-resistant has been found to give advantages to the weedy rice, even in the absence of the herbicide. The results suggest that the effects of such modification have the potential to extend beyond farms and into the wild.

ラウンドアップ A variety of crop varieties are genetically altered so that they can resist glyphosate. The herbicide was initially available under the trade name Roundup. The resistance to glyphosate permits farmers to get rid of weeds without causing any damage to their crops.

Glyphosate is a plant-killer by inhibiting EPSP synase which is an enzyme that plays a role in the creation of amino acids, as well as other chemical compounds that comprise about 35% of the plant's mass. Genetic modification is used for instance, in Roundup Ready plants made by Monsanto Biotechnology Inc., a biotech firm that is headquartered in St Louis, Missouri. It involves inserting genes into the genome of the crop to increase EPSP synthase-synthase-production. Genes are usually derived from bacteria that are infected with plants.

This extra EPSP synthase allows plants to counteract the effects from glyphosate. Biotechnology labs have tried using genes from plants to boost EPSP synthase production. This was done in part to take advantage of a loophole in US law that allows regulatory approval of organisms containing transgenes that are not derived from pests caused by bacteria.

ラウンドアップ A few studies have looked into whether transgenes that confer glyphosate tolerance could -- after they become weedy or wild relatives by cross-pollinatingenhance the plant's survival and reproduction. Norman Ellstrand of the University of California, Riverside, said that the traditional expectation was that any transgene would be detrimental to nature if there was no selection pressure. This is because any extra machinery could reduce the effectiveness of.

Lu Baorong (an ecologist at Fudan University, Shanghai) has since challenged this view. It shows that resistance to glyphosate can provide a significant fitness boost to the weedy rice crop called Oryza Sativa even when not in use.

In their study, published this month in New Phytologist 1, Lu and his colleagues genetically modified the rice plant to enhance its own EPSP synthase. They also crossed-bred the altered rice with a weedy cousin.

The researchers then allowed the offspring of cross-breeding to be bred with one another to create second-generation hybrids. These were genetically identical except for the copy count and number of the EPSP synthase gene. As one would expect, more copies resulted in higher levels of enzyme, and also more tryptophan, than their counterparts that were not modified.

ラウンドアップ Researchers also discovered that transgenic plants were more photosynthesis-intensive as well as produced more flowers and produced 48-125percent less seeds per plant than the nontransgenic hybrids. This was in spite of the fact that glyphosate was not present.

Lu believes making weedy, invasive rice more competitive may make it harder for farmers to repair the damage caused by this pest.

ラウンドアップ Brian Ford-Lloyd, a researcher at the University of Birmingham, UK Brian Ford-Lloyd, a researcher at the University of Birmingham in the "If the EPSP synthase gene is introduced to wild rice species, their genetic variety that was so important for conserving, could be threatened because it would outcompete the normal varieties." "This is an example of the most probable and damaging negative effects of GM crops on the environment."

The study also challenges the public perception that genetically modified crops with extra copies of their own genes are safer than those that contain the genes of microorganisms. Lu says, "Our study shows this is not necessarily true."

ラウンドアップ A few researchers believe this discovery needs to be reviewed in light of future regulation of crops that have been genetically modified. "Some individuals are saying that biosafety regulations are relaxed because we have an extremely high level of satisfaction in the last two decades of genetic engineering," says Ellstrand. https://rd.listing.yahoo.co.jp/p/search/GU=A-aJT2MAACleN1FDIrpPeI0jRvZ_SfYgipqm5QmGMEGH_Cyd7fue2mQevTBXr1bbM5MKVkptzmMsahLVFzwO7gqRpQqHN084dT1VxlT1aHK5kdpjv0Rma5XxUhnyqxTB0AQebMfPzPnTzC0niakcplqXRIi1M1pC7F4iXBxz_TQ9-ObHa2mdtE6XNrupPvE2Fc7kI9ny2K1FIJEKlOG3qlkHjmA0O8XAi9IfRQLxLuqM1pilnZWtlZwS742AseC1qsEtRb4s8jKjdDr00PqEKBM5heN4NWm5610SfjAiJldABIJIiYqyww8p99BCS9sUMJ9SvQc8f_-h2lIgnMjSIbiOfCGEKd9wuWt2ggI5mGWiJ38bOo5R8jgKea1M6efVXCRG59PzcViJcT5XDoLoR5TpEYlF9gAAbUNltbGfIhYbOLtlOGG4_9Dlsmge1mZpqRq4RXACe1ncBeZtYkeB3dtj-8-2E5N19fn7bowQ6E29JvgCUHg-2hu2-R7sGpu9L5ERe5P8EReIiOz1AkKS88Iiom0RWIiI4Robxzkiep_HURiaWxGr2RmCzgaaAlKgtrGkrDY-OAP0_v0vyQC61Hs5Iy674JSUOu7PUpq8XDUGHSH2BmuCF4UmZeHKwRsuanYO_rnxesecWSTkOmAtyRkiTBa90cY_fnEus8oPVIgktN067qcthhONnnGodt4NPRexZEKdAldsfNp-fQvCFpAriHlZZAKUdbtjAhwOnNp94E-gnIBb9wS4AELA3CeK2l1UmK3wSvIAecWPwXT8sM8t9KFDGb1HF1V5ywfY2dgn-nPg-erzWx7-7anCK0g2MMdDJJ-vfj6hJE060SqlkkrJl3c3OWqV8QX4ArhLnAMJ5Ox9l_iKd5J_zoLKr23U7jK1GEaGPSDQIP5uJ522EpNNv2if1fCQ5A8A_WHgxwYAYiDjLOoUDmZujrJdjkPy5DQjRVtfol-NVOwXtU9lWPDkHACzloWORD6sc7Og3tGjwJS4eORUmBg5UaTxNLbjOD1P8QCecDH6Ex7kZLrwpULksx6kyEs;/?ep=A-aJT2MAAPTTWODN2FCiS7Hrm5W8RKRObSoVsQAhRcW8MQYo_TUzpRh3BxATOTdEY2nNnybtKAwqaycf-GFm177NyxSHKv0oOOQ8OP2jLkibZgR8KojDaJcwTI8471Nj2jOWG6DWcINaPJlD3-ZWC4T3OYd5q7DOdjz2zxhH-giC7rrwcBGXJcEeGMTtxVttR1G2wPEct4-IbywtrdKprAGXSEiegcWjOV1m&v=2 "But, the study showed that the new technologies still need to be evaluated with care."


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