first_img Click to view the privacy policy. Required fields are indicated by an asterisk (*) Soy leafFungus Email Country * Afghanistan Aland Islands Albania Algeria Andorra Angola Anguilla Antarctica Antigua and Barbuda Argentina Armenia Aruba Australia Austria Azerbaijan Bahamas Bahrain Bangladesh Barbados Belarus Belgium Belize Benin Bermuda Bhutan Bolivia, Plurinational State of Bonaire, Sint Eustatius and Saba Bosnia and Herzegovina Botswana Bouvet Island Brazil British Indian Ocean Territory Brunei Darussalam Bulgaria Burkina Faso Burundi Cambodia Cameroon Canada Cape Verde Cayman Islands Central African Republic Chad Chile China Christmas Island Cocos (Keeling) Islands Colombia Comoros Congo Congo, the Democratic Republic of the Cook Islands Costa Rica Cote d’Ivoire Croatia Cuba Curaçao Cyprus Czech Republic Denmark Djibouti Dominica Dominican Republic Ecuador Egypt El Salvador Equatorial Guinea Eritrea Estonia Ethiopia Falkland Islands (Malvinas) Faroe Islands Fiji Finland France French Guiana French Polynesia French Southern Territories Gabon Gambia Georgia Germany Ghana Gibraltar Greece Greenland Grenada Guadeloupe Guatemala Guernsey Guinea Guinea-Bissau Guyana Haiti Heard Island and McDonald Islands Holy See (Vatican City State) Honduras Hungary Iceland India Indonesia Iran, Islamic Republic of Iraq Ireland Isle of Man Israel Italy Jamaica Japan Jersey Jordan Kazakhstan Kenya Kiribati Korea, Democratic People’s Republic of Korea, Republic of Kuwait Kyrgyzstan Lao People’s Democratic Republic Latvia Lebanon Lesotho Liberia Libyan Arab Jamahiriya Liechtenstein Lithuania Luxembourg Macao Macedonia, the former Yugoslav Republic of Madagascar Malawi Malaysia Maldives Mali Malta Martinique Mauritania Mauritius Mayotte Mexico Moldova, Republic of Monaco Mongolia Montenegro Montserrat Morocco Mozambique Myanmar Namibia Nauru Nepal Netherlands New Caledonia New Zealand Nicaragua Niger Nigeria Niue Norfolk Island Norway Oman Pakistan Palestine Panama Papua New Guinea Paraguay Peru Philippines Pitcairn Poland Portugal Qatar Reunion Romania Russian Federation Rwanda Saint Barthélemy Saint Helena, Ascension and Tristan da Cunha Saint Kitts and Nevis Saint Lucia Saint Martin (French part) Saint Pierre and Miquelon Saint Vincent and the Grenadines Samoa San Marino Sao Tome and Principe Saudi Arabia Senegal Serbia Seychelles Sierra Leone Singapore Sint Maarten (Dutch part) Slovakia Slovenia Solomon Islands Somalia South Africa South Georgia and the South Sandwich Islands South Sudan Spain Sri Lanka Sudan Suriname Svalbard and Jan Mayen Swaziland Sweden Switzerland Syrian Arab Republic Taiwan Tajikistan Tanzania, United Republic of Thailand Timor-Leste Togo Tokelau Tonga Trinidad and Tobago Tunisia Turkey Turkmenistan Turks and Caicos Islands Tuvalu Uganda Ukraine United Arab Emirates United Kingdom United States Uruguay Uzbekistan Vanuatu Venezuela, Bolivarian Republic of Vietnam Virgin Islands, British Wallis and Futuna Western Sahara Yemen Zambia Zimbabwe 5 nanometers Dan Ross/ By Erik StokstadApr. 25, 2019 , 12:10 PM Attaching a fluorescent protein to the anchor peptides showed that about 60% to 70% of the leaf remained covered with them, even after the plant was doused in a rain simulation chamber. These two anchor peptides also clung well to the leaves of barley, corn, blueberry, and other crops. Schwaneberg says they can be engineered to adhere more or less tightly, as desired.The next step was to attach an antimicrobial peptide to the anchor. The team chose dermaseptin, a peptide discovered years ago in the skin of tree frogs. Dermaseptin attacks a broad array of microbes, including bacteria and fungi, somehow rupturing their cell membranes. Conrath notes that pathogens are much less likely to evolve resistance—a problem with chemical pesticides—because it is difficult to change the basic structure of cell membranes.When tested on glass slides, the fused peptide was about as effective against soybean rust spores as chemical fungicides. But in lab tests on plants, the peptide reduced symptoms of rust by only about 30%. “It’s not enough,” says Emilio Montesinos, a plant pathologist and agronomist at the University of Girona in Spain. “If you want to extend these results for crop protection, you need to do much more work.” Conrath thinks a tactic already used by industry for other pesticides could yield more potent peptides: adding chemicals to distribute them evenly across leaves.He acknowledges that the peptides are only at the beginning of the pesticide development process, which can last a decade and cost $200 million on average. RWTH Aachen has patented the concept, and Conrath and Schwaneberg plan to start a company to pursue deals with large pesticide manufacturers. They will need help lowering the cost of making the peptides. One way—engineering microbes to produce the peptides themselves in industrial vats—can be tricky when the desired protein tends to kill the microbes that make it.Another question is safety. Dermaseptin would need to be evaluated for its possible toxicity to humans, as well as the accidental harm it could cause to beneficial insects, fungi, or microbes. “It’s broad-spectrum and it’s persistent, and that creates a regulatory concern,” says Roma Gwynn, who runs Rationale, a pesticide consultancy in Duns, U.K.Studies indicate that dermaseptin does not harm mammalian cells, and any residues could be removed by washing the plant product with enzymes. Microbes would likely break down peptides remaining in the fields, Conrath says.As for target pathogens, the team is already thinking beyond soybean rust. They have showed that dermaseptin-based peptides can help protect maize from the common fungus Colletotrichum graminicola. They also want to try attach ing the anchor peptide to Bacillus thuringiensis, or Bt, a insect-killing microbial toxin widely used by organic farmers and engineered into transgenic crops.Before that, however, Conrath and Schwaneberg plan to outfit their anchors with tiny amounts of copper, commonly used by vineyards and organic farms to fight fungi and other pathogens. This fall, with a €1 million grant from Germany’s Federal Ministry of Food and Agriculture, the team will test the approach in vineyards in southern Germany, which could reduce copper spraying and the runoff that contaminates soil. They’re hoping the idea will stick. Sign up for our daily newsletter Get more great content like this delivered right to you! Countrycenter_img Waterproof protectionAn antimicrobial protein has been designed to stick to leaves in the rain. One part of the protein is anchored in leaf wax. The other ruptures membranes of fungal spores.{font-family:’Roboto Condensed’,’Helvetica Neue’,Helvetica,Arial,sans-serif;font-weight:bold;}{font-family:’Roboto Condensed’,’Helvetica Neue’,Helvetica,Arial,sans-serif;font-weight:bold;font-style:italic;}BOLDREGULARITALICBOLD ITALIC{font-family:’Roboto Condensed’,’Helvetica Neue’,Helvetica,Arial,sans-serif;}{font-family:’Roboto Condensed’,’Helvetica Neue’,Helvetica,Arial,sans-serif;font-style:italic;}REPLACE {font-family:’RobotoCondensed-Bold’;} etc WITH: Sticky proteins could protect crops more safely than chemical pesticides (GRAPHIC) V. ALTOUNIAN/SCIENCE; (DATA) GAURAO DHOKE AND MEHDI DAVARI DOLATABADI/RWTH AACHEN UNIVERSITY Sticky molecules could help soybean plants fight off a fungus even when it rains. To make the new pesticide, plant pathologist Uwe Conrath and protein engineer Ulrich Schwaneberg of RWTH Aachen University in Germany teamed up. Schwaneberg specializes in the directed evolution of peptides—adding genes to microbes to produce them, for example, and relying on rounds of mutation and selection to develop strains that produce peptides with improved traits. He has created peptides that attach to slick surfaces such as polypropylene. The team found two that also anchor themselves onto soy leaves. Spore (not to scale)CellLeaf waxAnchorDermaseptin Many pesticides have an inherent weakness: The active ingredients don’t adhere well to the plants they protect. After the chemicals are sprayed onto crops, rain can wash them off into the soil and groundwater. Farmers must spray again and hope for dry weather.Now, researchers have devised a stickier approach to protecting plants, one that could be applied less frequently than chemical pesticides and might be less toxic. They have designed a molecule with two separate chains of amino acids, called peptides. One peptide embeds itself in the waxy surface of a leaf, holding tight in the rain; the other juts out like a spear to attack microbial pests. In a proof of concept published this month in Green Chemistry, lab tests showed the molecules lessened symptoms of soybean rust, a dreaded fungus that causes one of the world’s worst agricultural diseases.The peptides will face many challenges before they can reach the market. But plant pathologists say they could be a flexible new way to protect crops. “With the current scale of the soybean rust problem, and the rapid evolution of resistance against multiple fungicides, any addition to the toolbox would be welcome,” says Nichola Hawkins at Rothamsted Research in Harpenden, U.K. Ralph Hückelhoven at the Technical University of Munich in Germany also considers the technique promising. “It opens a treasure box of solutions,” he says. “It’s a bit surprising that no one has done this before.”last_img

Leave a Reply

Your email address will not be published. Required fields are marked *