Methods for control of hemipteran insect stylet sheath structure formation
Inventors
Shatters, Robert G. • Luzio, Gary A. • Morgan, John K.
Assignees
US Department of Agriculture USDA
Publication Number
US-9949489-B2
Publication Date
2018-04-24
Expiration Date
2036-04-28
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Abstract
Compositions having at least one compound which inhibits the formation of Hemipteran stylet sheaths and/or degrades hemipteran style sheaths that have already been formed, and thus deters or blocks hemipteran insects from feeding on plants, especially agriculturally important plants and methods of use of such compositions are described. Such compositions can be applied onto plants by spraying, dripping, or other methods and/or can be applied to the soil for uptake by the roots. These compositions and methods prevent and/or reduce the transmission of vascular associated diseases (caused by hemipteran vector-borne pathogens) to plants.
Core Innovation
The invention provides compositions containing at least one compound that inhibits the formation of hemipteran stylet sheaths, degrades stylet sheaths that have already been formed, or deters or blocks hemipteran insects from feeding on plants, especially agriculturally important plants. These compositions can be applied onto plants by various methods such as spraying, dripping, or soil application for root uptake. The invention also provides methods for using these compositions to prevent or reduce transmission of vascular-associated diseases caused by hemipteran vector-borne pathogens to economically important plants.
Hemipteran insect pests feed by penetrating plant tissues and produce oral secretions that solidify into stylet sheaths essential for feeding and survival. Stylet sheaths are solid hollow tubes extending from the leaf surface to the feeding site, often vascular tissue. These sheaths provide directional stability, aid in feeding, cloak stylets from host defenses, and rapidly seal cell penetration points to prevent perception of plant damage signals. However, prior to this invention, little was known about how to prevent hemipteran insects from feeding on plants or spreading devastating diseases.
The invention addresses the need for novel compositions and methods that inhibit or reduce the feeding of hemipteran insects on economically important plants by targeting stylet sheath formation or degradation. This blocking strategy differs from systemic pesticides and aims to prevent insects from reaching plant vascular tissue, thereby reducing transmission of vascular diseases. The invention includes compositions comprising proteins such as proteases and carbohydrate-degrading enzymes and/or small molecules including metal chelating agents that inhibit stylet sheath formation or degrade existing sheaths, as well as methods to apply these compositions effectively to plants.
Claims Coverage
The patent presents three main inventive methods covering inhibition of stylet sheath formation, degradation of stylet sheaths, and reduction or prevention of transmission of vascular-associated diseases by hemipteran insects using specific compositions.
Method to prevent hemipteran stylet sheath formation
A method comprising applying to a plant a composition with an agriculturally acceptable carrier and at least one compound effective to prevent stylet sheath formation. The compound is selected from carbohydrate-degrading enzymes, proteases, small molecules that prevent stylet sheath formation, or combinations thereof.
Proteases effective in preventing stylet sheath formation
Proteases suitable for preventing stylet sheath formation include cellulase, protease from Aspergillus oryzae, carboxypeptidase, chymopapin, papain, bromelain, ficin, proteinase K, calpain, caspase, cathepsin, actinidin, tobacco etch virus protease, γ-glutamyl hydrolase, and combinations thereof.
Carbohydrate-degrading enzymes effective in preventing stylet sheath formation
Enzymes effective for preventing stylet sheath formation include amyloglucosidase, α-amylase, laminarinase, licheninase, cellulase, hemicellulase, glucuronyl hydrolase, lytic polysaccharide monooxygenase, β-1,4-endoglucanase, endo-1,3(4)-β-glucanases, endodextranase, xylanase, mannan-degrading hydrolase, and combinations thereof.
Small molecules effective in preventing stylet sheath formation
Small molecules include 3-aminopropionitrile fumarate salt, dithiothreitol solution, nitrilotriacetic acid trisodium salt, 4-hydroxybenzyl alcohol, kojic acid, ammonium tetrathiomolybdate, EDTA, D-penicillamine, various tetramines and tetraazacyclotetradecane derivatives, flavonoids such as naringin, didymin, eriodictyol, eriocitrin, hesperetin, naringenin, 7-hydroxy-coumarin, limonin, limonin glucoside, nomilin, and combinations thereof.
Small molecules as copper chelating agents or laccase inhibitors
The small molecules can specifically be copper chelating agents or laccase inhibitors effective in preventing stylet sheath formation.
Adjuvants to enhance composition efficacy
Adjuvants optionally included in the compositions comprise buffers, penetrating agents, surfactants, oils, humectants, or combinations thereof to aid application and activity.
Method to degrade hemipteran stylet sheaths
A method comprising applying to a plant a composition effective to degrade hemipteran stylet sheaths containing a carrier and at least one compound capable of degrading sheaths, selected from carbohydrate-degrading enzymes, proteases, small molecules, or combinations thereof.
Proteases effective in degrading stylet sheaths
Proteases capable of degrading stylet sheaths include cellulase, protease from Aspergillus oryzae, carboxypeptidase, chymopapin, papain, bromelain, ficin, proteinase K, calpain, caspase, cathepsin, actinidin, tobacco etch virus protease, γ-glutamyl hydrolase, and combinations thereof.
Carbohydrate-degrading enzymes effective in degrading stylet sheaths
Enzymes suitable for degrading stylet sheaths include amyloglucosidase, α-amylase, laminarinase, licheninase, cellulase, hemicellulase, glucuronyl hydrolase, lytic polysaccharide monooxygenase, β-1,4-endoglucanase, endo-1,3(4)-β-glucanases, endodextranase, xylanase, mannan-degrading hydrolase, and combinations thereof.
Small molecules effective in degrading stylet sheaths
Small molecules effective at degrading stylet sheaths include various named compounds as in prevention, with the added characterization as copper chelating agents or laccase inhibitors.
Method to reduce or prevent transmission of vascular-associated diseases
A method for reducing or preventing transmission of vascular-associated diseases caused by hemipteran insects by applying compositions that prevent or degrade stylet sheaths, thereby preventing or reducing insect feeding and pathogen transmission.
The claims cover methods utilizing specific compositions containing enzymes and small molecules that either prevent formation or degrade hemipteran stylet sheaths to deter insect feeding, thereby reducing plant damage and disease transmission. These methods use proteases, carbohydrate-degrading enzymes, small molecules including metal chelators, and appropriate adjuvants applied in effective amounts to plants.
Stated Advantages
The compositions and methods prevent and/or reduce transmission of vascular-associated diseases caused by hemipteran vector-borne pathogens to economically important plants.
Preventing or reducing hemipteran feeding by inhibiting or degrading stylet sheaths reduces crop loss and damage to plants.
The compositions act before the insect can reach the plant vascular tissue, blocking feeding and pathogen transmission, differing from systemic pesticides that allow brief feeding before insect death.
Various enzymes and compounds effectively degrade or prevent formation of sheaths, providing multiple options for controlling hemipteran pests.
Documented Applications
Application of compositions on plants by spraying, dripping, dipping, drenching, or soil application for uptake by roots to prevent or reduce hemipteran feeding.
Using compositions to prevent or reduce transmission of vascular-associated diseases such as citrus greening disease.
Treatment of economically important plants, including citrus, to reduce hemipteran insect damage and disease spread.
Use of feeding chambers and artificial diets containing enzymes or small molecules to study and inhibit hemipteran feeding and stylet sheath formation.
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