811 . 14 Cuscuta is universal to spp., but more significant C. campestris DA-ARS, Water Management Research , Suite 320, Fort Collins, CO 80526, USA. Cuscuta and is in the public domain in the USA Willd. were resistant to imazamox however, these plastids are probably has not been reported as a problem in was allowed to establish on all oilseed 10–12 C. gronovii ollins, CO 80527, USA Understanding the importance of the chloroplast C. campestris 13 Cuscata campestris Correspondence to: Dale L Shaner,Unit, US 2150 Center Avenue BuildingE-mail: [email protected] D Weed Science Lab, Biological ScienceUniversity, Fort and C Pest Management, Colorado State The three amino acid biosynthesis inhibitors examined in Although growth on the imidazolinone-resistant host. The growth of ∗ 0 January 2009 Published online in Wiley Interscience: 16 April 2009 this studychloroplast. all Glyphosate inhibits aromatic inhibit amino acid biosynthesis byinhibitingenolpyruvylshikimate-3-phosphatesynthase(EPSPS), biosynthetic pathwayswhile a located large group of acetolactate synthetase in (ALS) inhibitorsthe stop the biosynthesis of branchedinhibits glutamine chained synthetase, amino the acids. initialassimilation of Glufosinate enzyme inorganic involved nitrogen in into organic the forms. in a parasite’sinhibited by metabolism some of the is main herbicidechloroplast a families (e.g. are photosynthesis, located significant in amino the acid, issue, chlorophyllbiosynthesis). and lipid as pathways more functional than previously thoughtsynthesis. with respect to protein oilseed rape, this cropcould was be easily chosen infested as with a model host because it accessory pigments; is the availability of glyphosate-,resistant imidazolinone- varieties. and glufosinate- The primary objective of this research was to vide new management strategies for the control of parasitic L.) genotypes were used to examine the response of attached Durand & Hilg. and ss likely to recover when it had low compatibility with the host, Scott Nissen, Phill Westra and the ∗ attached to glufosinate-resistant oilseed rape had little impact on The icide resistance could be highly effective in controlling 9 These 2,5 8 C. campestris L.). ? icating that resistance initially discovered in spp. differs Brassica napus Yuncker was able C. campestris 7 Cuscuta to recover was related to the quality of interaction between the host and parasite and Beta vulgaris spp. compared with its spp. spp. are above-ground, and connects to the host’s C. campestris, C. subinclusa Striga 2,3 Cuscuta Cuscuta Cuscuta to glyphosate and sulfometuron 1 and 6 C. campestris Cuscata campestris spp. have functional chloroplasts, spp. family are considered among the most spp. : 811–816 www.soci.org This article is a US Government work Yuncker to glyphosate, imazamox and glufosinate. ; dodder; herbicide resistance; transgenic crops; amino acid inhibitors forming a highly efficient absorption system C. campestris 65 Cuscuta 4 Cuscuta Orobanche Cuscuta on glyphosate-resistant host was initially inhibited by glyphosate, but the parasite recovered and resumed growth 2009; species. Glufosinate applied to Cuscuta

Cuscuta This same combination of technologies has been less successful success for root parasites. This initialif work the also resistance did of not determine resulted from metabolism, lack of translocation within the parasite, sequestration or insensitive sites ofextent action in to the chloroplast. which The the basic physiology of Cuscuta campestris the parasite, while imazamoxC. completely campestris inhibited within 3–4 weeks. CONCLUSION: The ability of to the resistance mechanism of the host. The parasite was le Keywords: rape genotypes before herbicides were applied. RESULTS: Unattached seedlings of and glyphosate and sensitive to glufosinate, ind indicating that parasite-resistant crops coupled withPublished herb 2009 by John Wiley & Sons, Ltd. from non-parasitic, higher plantsthe and the parasite’s relative own importance biosyntheticdefined. of pathways Although have not been clearly findings suggest thatnot herbicide-resistant be as crop successful technology in managing may to recover from glyphosate andattached sulfometuron to herbicide-resistant applications sugar when beet ( for control of vascular bundles, parasite can also divert and accumulate phloem-mobile herbicides absorbedbythehost.Thecombinationofherbicide-resistantcrops and phloem-mobile herbicides has been usedplants to such control as parasitic Pest Manag Sci Members of the damaging parasites worldwide. 1INTRODUCTION plants. Three herbicide-resistant oilseed rape ( BACKGROUND: Herbicide-resistant crop technology could pro all Abstract controlling Talia Nadler-Hassar, Dale L Shaner, (www.interscience.wiley.com) DOI 10.1002/ps.1760 Are herbicide-resistant crops the answer to Research Article Received: 17 November 2008 Revised: 15 January 2009 Accepted: 2 plastids contain only small amounts of chlorophyll and other absolute parasites that must make contact within a order to susceptible survive. host Once a rootless parasite seedlingwith makes contact a host, it develops haustoria that enables the parasite to divert resources from the host. Baruch Rubin . ) ) 8 C 1 1 ◦ − − et al 200 and : 811–816  65 species were -infested and seedlings can species tested 2009; values calculated ). Pots containing were insensitive to 1 50 − Cuscuta (the rate causing 50% Cuscuta Cuscuta 50 seeds were sown in the population tested in Israel. C. campestris ), glyphosate (750 g AE ha values indicate the goodness C. gronovii of glyphosate (0, 188, 315, 1 2 − Pest Manag Sci 1 R − and ). Treated pots were monitored to . The three Cuscuta 1 8 species to imazamox was consistent − values of all three 05 level by Tukey’s multiple comparison C. campestris . seeds were sown close to the developing 0 shootsegments(10 cmlong)aroundoilseed 50 ), imazamox (0, 10, 20, 40, 80 g AE ha 1 Cuscuta = − The calculated P 17 species and WT oilseed rape were in the range Cuscuta values for glyphosate were in a range similar to the -infested WT oilseed rape and parasite-infested tissue were harvested and separated for fresh and dry 50 (The Scott’s Company, USA) once a week. Herbicides )foundfora C. campestris M  Cuscuta Cuscuta (52 m Tissue fresh weight data collected for pot assays after treatment 50 glyphosate and imazamox when theya were grown host alone (Table without 1). The I procedure using JMPIN 5.1 software (SAS Institute, Inc., USA). similar to those calculated for herbicide-resistant oilseed rape.calculated The I Horticultural Products Co., USA). At 5scarified DAS, approximately 30 acid- oilseed rape seedlings.control pots. Pots No were kept in the greenhouse at 21–27/14–18 were extremely sensitive to glufosinate. The I for all or glufosinate (0, 50, 100, 200, 400 g AE ha or glufosinate (400 g AE ha non-infested oilseed rape with acalibrated laboratory chain-driven to sprayer deliver 200 L ha (commercial formulations) were applied to The response of all with previous results showing that 3RESULTS 3.1 Seedling bioassay Cuscutacampestris,C.subinclusa tolerate other ALS inhibitors (day/night), watered as needed and fertilized with 20-20-20fertilizer Peter’s incubated under the same conditionsweeks as after described sowing, above. the Three twodetached oilseed rape was parasitizedrape plants. by Two coiling weeks later,sprayed successfully with parasitized imazamox (20 plants g were AE ha with herbicides wereseparated at analyzed the by ANOVA, and means were reduction in tissue elongation) wasand seed predicted variety. for each herbicide I C. campestris imidazolinone-resistant, glyphosate-resistantresistant and oilseed rape glufosinate- wereand glufosinate treated respectively. Host and with parasite development imazamox, were monitored glyphosate and graded beforeassessment time, and 25 days after after treatment treatment. (DAT)DAT At for for glufosinate, imazamox the 34 and final 41 DATparasite for were glyphosate, scored the from host 0 plant (dead)and and to 5 (full vigor). The host plant 750, 1500 g AE ha of fit of each calculated curve from which I detect signs of recovery until 90 DAT. 2.5 Statistical analysis Seedling dose–response assays wererandomized conducted design in with a three completely replications.software Using (Systate Sigma Software Plot 9.0 Inc.,gation USA), data were the analyzed shootequation using model. and a root sigmoidal elon- logistic regression weight determinations. 2.4.2 Large potRape assays seeds were sown in 4.8 L pots containing Metro Mix ; ; ; 1 M in    − Cuscuta SL (Rely www.soci.org T Nadler-Hassar 1 SL (Raptor − 1 This article is a US Government work − and is in the public domain in the USA C. campestris Sorghum bicolor Cuscuta subinclusa pellets(Scott-Sierra shoot lengths were ), imazamox (0, 0.01,  M ) or glufosinate (0, 0.01, C. campestris, C. gronovii M µ 15 SL (Roundup WeatherMAX shoot lengths were measured seeds were cleaned and acid ) dilutions made up in 10.0 m 1 C. gronovii M − (collected in Colorado, USA), while attached to herbicide-resistant Cuscuta Durand & Hilg. to these herbicides as C. subinclusa and C. campestris Seeds were placed on sheets of germination paper was added to all glufosinate applications. In order to C. subinclusa 16 . 1 Cuscuta campestris − (collected in Massachusetts, USA) and et al 200 potting soil (Scott-Sierra Horticultural Products Co., 25 cm; Seedburo Equipment Co., USA) soaked in glyphosate C; no additional solution was added during the experiment.  × ◦ 2.4 Pot assays 2.4.1 Small potRape assays seeds were sownMix in 0.67 L plastic pots containing Metro 5 days after sowingmeasured (DAS), 6 while DAS. The rootwere measured lengths 4 of and 5 sorghum DAS and respectively. oilseed rape 0.1, 1.0, 10, 100, 1000, 10 000, 100 000 improve glufosinate absorption,treatment pots to increase were humidity watered levels. 1 h before USA)supplementedwith14-14-14Osmocote Monsanto, USA), imazamox-ammonium 120 g AE L BASF, USA) and glufosinate-ammoniumBayer 120 g CropScience, AE USA) L were(Activator evaluated. 90; A Loveland Products, non-ionic Inc., USA) surfactant was added at 2.5 g L www.interscience.wiley.com/journal/ps phosphate buffer at5 pH cm 6.0. from the Seeds topsecured were of lightly placed the with a approximately sheet rubber andcovered band, with then a placed each plastic in sheet bag. a Beakers30 was glass were rolled, beaker incubated in and the dark at 2.3 Seedling bioassay Dose–response assays were performed on the basis ofof the method Tal to spray solution of all herbicides; in addition, ammoniumat sulphate 20 g L 2.2 Herbicides Glyphosate-potassium 550 g AE L gronovii (collected in California,oilseed USA) rape were in grownsupply the and of viable propagated greenhouse seeds. on scarified All to in maintain phosphoric acid aSeeds for homogeneous 20 of min toNetherlands) oilseed improve germination. with rape noherbicide-susceptible (cv. herbicide controls resistance Hyola (WT)treatments, for 420, and seeds were imazamox of Advanta a used sorghum(L.) and Moench] sudangrass Seeds, as [ hybrid glufosinate The were usedfor glyphosate as and imazamox. Two herbicide-susceptible imidazolinone-resistant (Hylite controls 289 CF, AdvantaHB, Seeds, Canada), a The glyphosate-resistant Netherlands,and (RR-DKL-35-85 Dekalb, and a USA) 46A76 glufosinate-resistantGermany) Pioneer oilseed (InVigor rape 2373, werethe herbicide Bayer used efficacy assays as CropScience, and as hostsfor herbicide-resistant the references for seedling bioassay. 2.1 Plant material Seeds of unattached seedlings was examined. 2 MATERIALS AND METHODS compare the efficacy offor glyphosate, control of imazamox and glufosinate 0.05, 0.1, 0.5, 1.0, 5.0, 10, 50, 100 m Cuscuta campestris (20 (0, 0.01, 0.05, 0.1, 0.5, 1.0, 5.0, 10, 50, 100 m oilseed rape. In addition, the response of Willd. and

812 813 a Cuscuta , recovery of C explants are Biomass (g fresh weight) plants maintained istant host. Percentage of C. campestris Cuscuta biomass(Fig. 3A);however, pattern of attachment to a , growth inhibition; B survival , control; C.campestris Percentage A www.interscience.wiley.com/journal/ps C. campestris parasitizes a young developing oilseed rape plants and biomass (g fresh weight) of parasite glufosinate: 1 attached to a glufosinate-res Effectiveness of glufosinate in the control of − ) Cuscuta 05 level. 1 . 0 − = C. campestris P Means followed by the same letter within a row are not different at Glyphosate applied at high rates to glyphosate-resistant oilseed Examination of the campestris surviving on glufosinate-resistant oilseedglufosinate (data rape are shown 25 as days the mean of after 5–6Glufosinate treatment plants) with (g AE ha Table 2. 050100200400a 100 100 100 100 100 9a 12a 21a 12a 7a the rapesignificantlyreduced of the initialtreatment, damage caused it toimidazolinone-resistant was the oilseed rape up parasite still to 80%. by Thisreduction host able the biomass occurred herbicide tothe when reduce oilseed the the rapedevelopment parasite that biomass lasted stem, even attachment after the of causing parasite encircled had died a the (Fig. 2B). severe restriction of stem host over time suggests that theherbicide parasite’s treatment ability is to dependent recover from onWhen the site of the attachment. at 34 DAT most of the herbicide-treated viable and recovering apexes (Table 3; Fig. 3B). plant, it penetratesstem. either If the the parasite host’s attaches onlybe lower to shed the leaf early lower leaves, when petioles it these is leaves orAlternatively, likely undergo to premature the if senescence. theplant, parasite it coils frequently around killsand the growth. the stem On host the of by other a hand, restricting when young stem expansion placed on older, well-developed plants, theto parasite attach is more to likely the upperhost. parts of the host and less likely to kill the 50 50 ) M µ ( of each I growth on Glufosinate 2 C. campestris R 50 and is in the public domain in the USA ) indicating the level M of the glufosinate- µ 17 ( 50 Imazamox attachedtoglufosinate- Herbicide I C. campestris AB C ) M – – 4.8 (0.85) –– 0.3 (0.97) 1130 (0.92) 0.04 (0.91) – had little effect on glufosinate (Table 2). Increasing . 1 (m 1 − M − 24.0 (0.96)13.1 9185 (0.97) (0.81)21.1 2618 0.06 (0.97) (0.93) (0.96) 0.08 8926 0.06 (0.97) (0.87) (0.94) 0.05 (0.99) 1.4 (0.97)25.6 (0.89) – – – µ Glyphosate 8 . ) inhibited on glufosinate-resistant oilseed rape treated with 400 g AE ha 1 − Cuscutacampestris : 811–816 This article is a US Government work attached to glufosinate-resistant oilseed rape 65 b glufosinate, whereas the I b 2009; a a M Seedling response to amino acid biosynthesis inhibitor a µ b Cuscuta campestris and herbicide-resistant crops www.soci.org b b 06 . oilseed rape rape rape Inhibition of root elongation. Inhibition of shoot elongation. 04–0 a b C. campestris Genotype herbicides as determinedvalues were in calculated using the a log-logistic model germination paper assay.calculated is The indicated in I parentheses) Table 1. Imidazolinone-resistant Glyphosate-resistant oilseed of sensitivity to each herbicide for each variety tested ( C. gronovii C. subinclusa S. bicolor WT oilseed rape Glufosinate-resistant oilseed . Cuscuta parasite. imidazolinone-resistant oilseed rape (Fig. 2A); however, in spite the glufosinate rate to 800 g ha control or reducing parasite damage to theImazamox host (data not (40 shown). g AE ha Pest Manag Sci Figure 1. 0 resistant oilseed rape was 4 3.2 Pot assays Cuscuta campestris was initially affectedrecovered by rapidly glufosinate (Fig. 1C) applicationshad and significantly (Fig. 1B), reduced by host but thethe biomass end (data herbicide not of shown).development(Table treatment the Thus, 2). experiment hadresistant very oilseed littletreatment rape impact with 50–400 recovered g on AE ha and parasite resumed growth after , , . B et al : 811–816 65 plants were imazamox; C.campestris gene, which 1 C. campestris − bar 2009; seeds collected in glufosinate could suggesting that the Cuscuta and are sensitive to 19 8 Pest Manag Sci to herbicides inhibiting amino C. campestris and host may activate different C. campestris seedlings tested in this study. The , indicating that the parasite contains however,theresponseof Cuscuta 16 Cuscuta Owing to the inactivation and limited on a host treated with 20 g AE ha and are a universal response of germinating 18 Imazamox applied to imidazolinone-resistant 8 20 C.campestris C. subinclusa and C. campestris shikimate and ALS assays confirm that the ALS and Therapidrecoveryoftheparasitegrownonglufosinate-resistant In vivo encodes an enzymeinactive that metabolite. rapidly acetylates glufosinate to an oilseed rape treated with glufosinate, in spiteto of the its high herbicide sensitivity in thethe seedling bioassay, mechanism is of most resistance likely into a the result glufosinate host. of Oilseed was rape facilitated resistance by inserting the tolerance of the parasiteand in imazamox the is seedling not bioassayaccumulation related to has to glyphosate been an detected altered byoilseed target rape and HPLC site. in Ammonia glufosinate-treated an active glutamine(data synthetase not shown). that These data is supportinteraction sensitive the between authors’ to theory the that glufosinate the processes in the parasite. in the seedling assayparasite did to not coincide the with samesuggests the herbicides either response when of that attached the evaluate this to the assay response a of is host.acid not This biosynthesis sufficiently or predictivespecial that to genes) various are initiated processes inthe (e.g. host the plants. parasite expression when of associated with EPSPS enzymes are active in oilseed rape would nottherefore be could rapidly readily accumulate metabolized in in the attached the host and Colorado and Israel, glufosinate are consistent among translocation of the herbicide in the host, be prevented from beingmolecule in accumulated the as parasite. Although analso attached sprayed intact with and glufosinate, the active could amount not of have herbicide been absorbed sufficientthe to herbicide kill primarily the gets parasite, to indicatingnot the that parasite by through the direct hostcontains and application. two modified Imidazolinone-resistant ALS genes oilseed thatresistant enzymes. encode rape for imidazolinone- C. gronovii ALS inhibitors and glyphosate respectively, dose–response seedling assaypredictanddistinguishbetweenherbicide-resistantandherbicide- has beensensitivecropsandweeds; used successfully to to , poor recovery of A plants Cuscuta Cuscuta Cuscuta survival www.soci.org T Nadler-Hassar Percentage ) 1 This article is a US Government work and is in the public domain in the USA − C. campestris C. campestris growing on both Rate initially inhibited the (g AE ha a AB C. campestris Biomass C. campestris on imidazolinone-resistant oilseed rape: (g fresh weight) Glyphosate Imazamox survival Percentage attached to herbicide-resistant hosts. Percentage of Effectiveness of herbicides in the control of ) 05 level. 1 . 0 − Cuscuta campestris = P Means followed by the same letter within a row are not different at In order to establish whether the quality of attachment between The fresh weight of a 01883757501500 100 80 100 60 36 40 a 8 12 b b 0.1 b 0.1 b 0 10 20 40 80 100 0 0 0 0 Rate (g AE ha Table 3. campestris plants surviving on imidazolinone-resistantcanola and after treatment glyphosate-resistant with imazamox andafter glyphosate treatment 34 respectively and 41 days the host growth constriction by parasite. the host and parasite determines the ability of seedlings to imazamox and glyphosate and their sensitivity to www.interscience.wiley.com/journal/ps 4The DISCUSSION dose–response assays confirm that the resistance of Figure 2. recoverfromimazamoxandglyphosatetreatments,explantsofthe parasite were used to parasitize older imidazolinone-resistantglyphosate-resistant and plants. Glyphosate appliedrape to host large plants infested oilseed with growth of the parasite for the first 3 weeksHowever, after it treatment (Fig. was 3A). observed that thethe parasite herbicide slowly damage, recovered resumed from growth (Table 3;(Fig. Fig 3C) 3B), flowered and setwere seed able to (Fig. recover 3D). from Only imazamoximidazolinone-resistant treatment oilseed a while rape attached few (Fig. to 2B). imidazolinone-resistant oilseed rape hosts was significantlythan lower that of theparasite parasite thrived grown on onglufosinate- all WT and other glyphosate-resistant oilseed hosts oilseedhigher rape (Fig. compatibility rape, 4). of the and indicating The parasite for a developed these cultivars. well on

814 815 , B on from Cuscuta ,18DAT; A Cuscuta actually re- Beta vulgaris Multiple ap- C. campestris and to ensure L.) or lucerne 30 to increase the 24 26 27 25 , C. campestris populations in the glyphosate: 1 − in lucerne. Cuscuta has a lower compatibility with C. campestris B Solanum lycopersicum during hot summers. would mature on a host C. campestris www.interscience.wiley.com/journal/ps . Both crops are sensitive to the parasite, C. campestris L.) resistant to either ALS inhibitors or glyphosate could be the quality of attachment between the As shown in the seedling assay, C. gronovii C. subinclusa 30 and further studies indicated that effective control of C. campestris 28 on tomato was achieved if herbicide was applied soon Cuscuta It has also been noted that the effectiveness of and California (Table 1) responded in the same manner to 8 29 The present results suggest that the most important factor in Medicago sativa imidazolinone-resistant oilseed rape ispossible that not the yet imidazolinone-resistant oil known,different seed levels but of rape branched chain it either amino acids has or is carriesthat other traits affect the ability of thereported parasite that to slight changes infest in the the host. internal It salinity has of been plications of rimsulfuron were needed to suppress tomatoes, control differed between fields and suggested that thewere differences the result of differencesvarious among fields. parasite has also beenlabelled reported nitrogen to from enhance the host the to translocation of the amino acid biosynthesisthat inhibitors. the Therefore, differences it observed is between possible the fields flected the quality ofthe the host. connection The reason between the parasite and ( to control determining the efficacy of aminocontrol acid biosynthesis inhibitors to host and parasite. Theand strong attachment glufosinate-resistant between oilseedovercome rape herbicide injury enabled and theapplications. to parasite recover These from to results hightiveness raise glufosinate questions of regarding using the tomato effec- ( Cuscuta after attachment and before thehost. parasite had established on the likelihood that the survival of Israel and it has been reportednot that sufficient one application to of control glyphosate was it 1,24 When (Table 3) 22,23 is reported to Achromobacter and is in the public domain in the USA was more likely to C. campestris C. campestris biomass on different oilseed growing on a glyphosate-resistant oilseed rape host to treatment with 750g AE ha C. campestris thus continuously exposing the appeared to be very compatible CD A 21 C. campestris than if attached to glyphosate-resistant . Thus, the parasite would be exposed to : 811–816 This article is a US Government work 8 Cuscuta campestris 65 ,90DAT. D 2009; C. campestris Cuscuta campestris Response of ,43DAT; and herbicide-resistant crops www.soci.org C The assay comparing Glyphosate-resistant oilseed rape contains two genetic modifi- Cuscuta rape hosts indicates that, even though less herbicide, resulting in reduced control and eventual recovery. recover from herbicide treatments whileresistant attached to sugar glyphosate- beet 29 DAT; be a non-selective parasite capable of invading many hosts, glyphosate is applied toof it glyphosate-resistant will oilseed be rape, metabolizedthe to part amount inactive of metabolites, intact hence glyphosateattached reducing that can be translocated to the soybean. These differencesof could attachment be between attributed theof to host good establishment and the and parasite. quality compatibility The between importance the host and Pest Manag Sci which acts as a ‘supersink’, Figure 3. parasite to a high dose of the herbicide. cations. It carries the CP4 EPSPSresistant EPSPS, gene and that a encodes second a gene that glyphosate- degrading encodes enzyme for – a glyphosate glyphosate- oxidoreductase (GOX).was This gene isolated fromsp. a and common rapidlyaminomethylphosphonic acid soil degrades (AMPA) and bacterium glyphosate glyoxylate. to non-toxic products, is not equally virulent toin all potential its hosts. ability The(Fig. parasite to 4). differed The thrive high efficacy on of different imazamox on varieties of the same host could be due toreduced compatibility. a Reduced compatibility combination might ofmajor mean avoidance that herbicide mechanism, a i.e. susceptibility branch chain and provided amino by acids the being host, isefficacy. reduced, leading to improved herbicide with the glyphosate-resistantcontributed oilseed to rape, the and parasite’sfrom this ability the to may host obtain have toobservations enough recover have nutrients from shown glyphosate that treatments. 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Lopez-Gutierrez JC and Purrington CB, Fitness of 25 Koch AM, Binder C and Sanders IR 24 Dawson JH, Musselman LJ, Wolswinkel P and Dorr I, Biology and 23 Padgette SR, Re DB, Barry GF, Eichholtz DE, Dalanay X, Fuchs RL, 17 Seefeldt SS, Jensen JE and Fuerst EP, 19 Beriault JN, Horsman GP and Devine MD, Phloem transport of 18 De Block M, Botterman J and Vemderwiele M, Engineering herbicide 20 Shaner DL, Bascomb NF and Smith W, 11 Weinberg T, Lalazar A and Rubin B, 13 Holm L, Doll J, Holm E, Panch J and Herberger J, 16 Tal A,Kotoula-Syka EandRubin B,Seed-bioassaytodetectgrassweeds 14 Devine MD, Duke SO and15 Fedtke C, Ramsey RJL, Stephenson Inhibition GR and Hall JC, of Effect of relative humidity amino on acid 21 Wolswinkel P, Phloem unloading in stem parts parasitized by 10 Dinelli G, Bonetti A and Tibiletti 12 Van Der Kooij TAW, Krupinshka K and Krause K, Tocochromanol 22 = .CAB Proc 4th Cassytha Cuscuta a :201–207 www.soci.org T Nadler-Hassar 6,7 220 The results of Plant CellEnviron This article is a US Government work and is in the public domain in the USA imidazolinone re- 31 :220–221 (1995). = b glyphosate resistant; ,Marburg,Germany, (dodder) and the g , The Hebrew University 374 = Protoplasma d: Biology and Control Nature b PhD Thesis – new structural results. seeds, and Tom Lanini for the control, there should be more species, the dodders, and C. campestris to infest the host. seeds. 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0.6 0.4 0.2 0.0 imidazolinone resistant (Advanta seed); IR-P = g dod/ g host g dod/ g P = 2 Tsivion Y, The regulation of the association3 of the Press MC, parasitic Graves GR plant and Stewart GR, Physiology of the interaction of 1 Parker C and Riches CR, 4 Vaughn KC, Dodder hyphae invade the host: a structural and 6 Joel DM, Kleifeld J, Losner-Goshen D, Herzlinger G and Gressel Y, 7 Kanampiu FK, Ransom JK and Gressel J, Imazapyr seed dressings for 5 Dorr I, The haustorium of supply of fresh weightEach of varietywild hosts had type; 35 over GLR daysIR 40 after pots sowing of the parasite-infested parasite hosts. seeds. WT emphasis on developing parasite-resistantherbicide resistance. hosts in addition to control is notneeds straightforward, to and be evaluated each onmost parasite–crop a economical case-by-case system system basis for managing toorder the determine to parasite, the achieve and efficient that, in www.interscience.wiley.com/journal/ps REFERENCES This research was supported in partFellowship by Vaadia-BARD Postdoctoral AwardStates–Israel No. Binational FI-348-2003 Agricultural ResearchFund, from and and Development BARD, inby part The the by US–Israel United GrantBureau Cooperative No. for Development Economic TA-MOU-01-CA20-006 Research Growth, funded Agriculturefor Program, International and Development. Trade, The US authors thank Agency for Frank the L supply Caruso of ACKNOWLEDGEMENTS tween the g fresh weight of reduced the ability of Figure 4. this research suggest that, unlike other parasitic plants, sistant (Pioneer seed). Bars containingthe the same letter are not different at

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