Archived at

Transcription

1 Control of Bremi ltue in Fiel-Grown Lettue y DL-3-Amino-n-Butnoi Ai () Y. Cohen 1, A. Bier 1, D. Gotlie 1, E. Ruin 1 Key wors: lettue, inue resistne, owny milew, eliitors, Bremi ltue Astrt DL-3-mino-n-utnoi i () ws effetive in ontrolling owny milew inite y Bremi ltue Regel in lettue plnts. The two isomers of, DL-2-mino-nutnoi i n 4-mino-utnoi i n its s-enntiomer were ineffetive ompres to, while the r-enntiomer ws more effetive. The SAR ompoun NSA n its funtionl nlogue BTH (Bion) were lso ineffetive ompre to. In growth hmers, ws effetive when pplie s folir spry or s soil renh. Effetive ontrol of the isese ws pprent when ws pplie up to 5 ys efore inoultion or 3 ys fter inoultion. A folir spry of 125 mg/l reue isese y 5% n full ontrol of the isese ws hieve with 5 mg/l. A soil renh with 1.25 mg /pot ws require for >9% ontrol the isese. In the fiel, 2-4 sprys with 1g/L reue isese severity y 9% s ompre to ontrol untrete plnts. h no verse effet on sporngil germintion of Bremi ltue in vitro, germintion on plnt lef surfe or, fungl penetrtion into the host. However, it prevente the oloniztion of the host with the pthogen.) Introution Downy milew use y Bremi ltue is the most serious fungl isese of lettue. The isese n e ontrolle y hemils inluing phenylmie (e.g. metlxyl)-se ompouns ut mutnt isoltes insensitive to these ompouns hve een reore (Crute et l., 1985; Crute et l., 1994; LeRoux et l., 1988). Disese resistne (R)-genes re lso use to ontrol the isese ut reominnt isoltes eving reognition onferre y the R-genes n our. An lterntive proeure to protet plnts ginst isese is to tivte their own efense mehnisms y speifi ioti or ioti eliitors (reviewe y (Wlters et l., 5)). The lssil type of inue resistne is often referre to s systemi quire resistne (SAR). Soium sliylte (NSA), 2,6-ihloroisoniotini i (INA) n enzothiizole-s-methyl ester (BTH), re well known eliitors of SAR in vrious plnts ginst isese (Stiher et l., 1997). The non-protein mino i DL-3-mino-n-utnoi i () lso tivtes n inue resistne response. It is ple of inuing systemi resistne ginst numerous pthogens (Cohen 2). One ojetive of this stuy ws to evlute the effiy of in ontrolling owny milew in lettue, espeilly uner fiel onitions. Fiel stuies with in lettue were not reporte efore. Another ojetive ws to stuy the mehnism of tion of ginst Bremi ltue in lettue. 1 The Min & Everr Goomn Fulty of Life Sienes, Br Iln University, Rmt Gn 529, Isrel <yohen@mil.iu..il> Arhive t

2 Mterils n methos The ultivr Nog (up type, Hzer Genetis, Mivhor, Isrel) of lettue (Ltu stiv L) ws use. Isolte Isr- of Bremi ltue Regel rrying 13 virulene ftors (, 1, 2, 3, 4, 5/8, 6, 7, 1, 11, 13, 15, 16, n 17) ws use for inoultions. For growth hmer stuies, plnts were grown from sees in ml pots ontining g pet/vermiulite mixture (1/1, v/v), plnts per pot. Plnts were grown in the greenhouse (18-32 C) n use one week fter seeing, when hve evelope two otyleon leves. DL-3-mino-n-utnoi i (), DL-2- mino-n-utnoi i (AABA), 4- mino- utnoi i (GABA), soium sliylte (NSA) n lofluor were purhse from Sigm, Isrel. Benzothiizole-S-methyl ester (BTH, Bion) ws gift from Syngent, Switzerln. All ompouns were issolve in wter efore use. Four fiel experiments were onute uring 5-6 to evlute the effiy of in ontrolling Bremi ltue in lettue plnts. Plnts were rise from sees in Speeling trys in the greenhouse. When plnts h 4 true leves, they were trnsplnte into polystyrene ontiners ( m) fille with pet + vermiulite (1/1, v/v), 8 plnts/ontiner. Continers were lote in she houses in the fiel t Br-Iln University Frm. She houses were overe with 5 mesh white plsti nets to voi phi n virl infetions. At out four weeks fter plnting, when they rehe the 1-12 lef stge, the plnts were trete with n inoulte with sporngil suspension of B. ltue (1 1 3 /ml) on the sme evening. After inoultion plnts were overe with plsti sheets for the night to ssure infetion., of vrious onentrtions, ws sprye with i of kpk mnul spryer t rte of out -3 ml/plnt. Experiments were one in full rnomize lok esign with 3-6 replites per ose tretment. Eh replite onsiste of 3 ontiners with 8 plnts in ontiner. Disese reors were tken y ounting the numer of owny milew lesions per plnt or y visul ssessment of the infete lef re in eh plnt. Results Resistne inue y minoutnoi is n SAR ompouns. The effiy of folir spry with DL-AABA, DL- n GABA in proteting plnts t their otyleon stge ginst owny milew is shown in Fig. 1A. Of the three isomers teste, only DL- ws effetive. Effiy of 7% ws exhiite t onentrtion of 125 mg/l n omplete inhiition of the isese ws hieve with 5 mg/l. Similr results were otine in plnts trete vi the root system (Fig.1B): soil renh with 2.5 mg per pot ( ml, ontining g of potting mixture) totlly inhiite the isese. Figures 1C n 1D show tht NSA n its funtionl nlogue BTH (Bion) pplie to the folige or the root system were oth ineffetive in proteting ginst the isese, suggesting tht the protetion y is proly meite y SA-inepenent pthwy(s). Fiel experiments. Results from four fiel experiments re presente in Figure 2A-D. Men perent infete lef re t the en of the seson in ontrol-untrete plnts ws 31, 29 n 45% in experiments A, C n D, respetively, wheres men of 63 owny milew lesions/plnt ws ounte in ontrol-untrete plnts in experiment B. In ll experiments, signifint (P=.5) reution in isese level ws hieve with 125 mg/l or ove. The higher the onentrtion of ws, the stronger n more signifint ws the suppression of the isese. In experiment C, of 25 mg/l or ove ws more effetive thn mnoze of mg/l (Fig. 2C). Perent isese ontrol y eh onentrtion of in eh experiment is given in

3 Figure 4E. Men % isese ontrol for ll 4 experiments is shown in Figure 4F. A orreltion of R2=.95 ws foun etween Ln onentrtion of n men % ontrol of the isese (Fig 2F). The lulte ose of require to hieve 5% n 9% ontrol of the isese ws 1 n 139 mg/l, respetively (Fig. 4F). A Folir spry B Soil renh Amino-utnoi i, mg/l AABA GABA Amino-utnoi i, mg/pot AABA GABA C Folir spry D Soil renh % Sporulting plnts r- s- Bion NSA r- s- BION NSA SAR ompoun, mg/l SAR ompoun, mg per pot Figure 1: Control of Bremi ltue in lettue y isomers or enntiomers of minoutnoi i or SAR inuing ompouns. Plnts t their otyleon stge ( plnts/pot, n=4) were sprye (A,C) or trete y soil renh (B,D) with vrious onentrtions of AABA (DL-2-mino-nutnoi i), (DL-3-mino-n-utnoi i) or GABA (4-minoutnoi i), r-bana, s-, Bion (BTH) or NSA n inoulte with sporngi of the pthogen one y fter tretment. At 5 pi plnts were trnsferre to % RH t C (12h light/y) to inue sporultion of the pthogen. Two ys lter (7 pi) the numer of sporulting plnts ws reore. In (B) n (D), 5 ml of solution (suspension in Bion) ws pplie to the soil surfe of eh pot ( g potting mixture/pot Disussion DL-3-mino-n-utnoi i (DL-β-minoutyri i, ) is non-protein mino i shown to inue resistne ginst out 5 plnt pthogens in lrge numer of nnul n perennil griulturl rops (Cohen, 2). Here we show tht ws effetive in ontrolling owny milew in lettue use y the oomyete Bremi ltue. In potte plnts, folir spry with 25 mg/l, or soil renh with 1.25 mg/pot soil, ws suffiient to suppress the isese y 9%. The two isomers AABA n GABA were ineffetive. The s-enntiomer of ws ineffetive wheres the r- enntiomer of ws more effetive ompre to. The SAR inuing ompoun NSA n its funtionl nlogue BHT (Bion) were ineffetive ompre to. A mjor fining of the present stuy ws tht ws effiient in ontrolling owny milew in lettue uner fiel onitions. Folir sprys with 1 n 139 mg/l

4 resulte with 5 n 9% ontrol of the isese, respetively. This my enourge the introution of to griulture s SAR ompoun ginst lettue owny milew. Due to the ft tht ours nturlly in tomto plnts (unpulishe t) it might lso e onsiere for pplition in orgni frming. Only limite numer of stuies were onute with in the fiel. Our own stuies showe effiy ginst owny milew in grpevines (Reuveni et l., 1), lte light in potto n tomto (Cohen, 2), rust in sunflower (Amzlek n Cohen, 7) n moly ore in pple (Reuveni et l., 3). A Novemer 5 B Jnury 6 Lesions per plnt , mg/l Lesions per plnt , mg/l C Ferury 6 D Novemer 6 % infete lef re MZ, mg/l % infete lef re D C B A 5, mg/l 14 pi 28 pi E Four experiments F Men of 4 experiments % isese ontrol , mg/l Nov-5 Jn-6 Fe-6 Nov-6 Men % isese ontrol y = 54.12Ln(x) R 2 =.9461 Figure 2. Control of owny milew in lettue y uner fiel onitions. A, B, C n D: The effet on isese evelopment in four experiments onute uring Novemer 5- Novemer 6. E: Perent isese ontrol in experiments A-D. F: Men % isese ontrol for experiment A-D. Plnts were grown in m polystyrene ontiners fille with pet+vermiulite (1/1, v/v) in four net houses (5 6 m eh) lote t BIU Frm. Plnts were sprye with (six onentrtions, mg/l, in experiments A-C n three onentrtions, 5- mg/l, in experiment D) n spry inoulte with sporngi of Bremi ltue few hours lter. To ssure infetion, plnts were overe with plsti sheets for one night following inoultion. A totl of 2, 4, 4, n 3 sprys were pplie in experiments A, B, C, , mg/l

5 n D, respetively. Sprys were pplie t 7-8 ys intervls. In experiment C, the protetnt fungiie mnoze ws inlue for omprtive purposes. Experiments were onute in fully rnomize esign with 3-6 replites per ose tretment. Eh replite onsiste of plnts, with 8 plnts /ontiner. Disese reors (visul ssessment of the perent lef re overe with lesions of owny milew in eh plnt, or the numer of lesions/plnt) were tken 17, 22, 25 pi in experiments A-C n t 14 n 28 pi in experiment D. Dt were sujete to Anov nlysis n seprte oring to Fisher's lest signifint ifferene test t P<.5. Different letters on olumns inite signifint ifferene in isese levels. Perent isese ontrol in E ws lulte s (x/y-1), when x = men % isese lef re in -trete plnts n y = men % isese lef re in ontrol-untrete plnts. Conlusions is shown here to effetively ontrol owny milew evelopment in lettue in growth hmers n the fiel. It is effetive when pplie to the folige or the roots. It exhiits post infetion (urtive) effiy n provies urle resistne ginst the isese. stops isese evelopment y suppressing fungl oloniztion. Aknowlegments The uthors grtefully knowlege funing from the Europen Community finnil prtiiption uner the Sixth Frmework Progrmme for Reserh, Tehnologil Development n Demonstrtion Ativities, for the Integrte Projet QUALITYLOWINPUTFOOD, FP6-FOOD-CT Referenes Amzlek, E. n Cohen, Y. (7): Comprtive effiy of SAR ompouns ginst rust infetion in sunflower plnts. Phytopthology 97: In Press. Cohen, Y. (2): β-minoutyri i-inue resistne ginst plnt pthogens. Plnt Dis. 86: Crute, I.R., Goron, P.I., n Moss, N.A. (1994): Vrition for responses to phenylmies in UK popultions of Bremi ltue (lettue owny milew) n Peronospor prsiti (Brssi owny milew). In: Heney, S., Slwson, D., Hollomon, D.W., Smith, M., Russel, P.E., Prry, D.W. (es.): British Crop Protetion Counil Monogrph No, pp Crute, I.R., Norwoo, J.M., n Goron, D.L. (1985): Resistne to phenylmie fungiies lettue n Brssi owny milew. Proeeings of the Mixture Centenry Meeting, Boreux, British Crop Protetion Counil Monogrph No 31: LeRoux, P., Misonneuve, B., n Belle, Y. (1988): Detetion en Frne e souhes e Bremi ltue, gent u miliou e l litue, resistntes u metlxyl et l'oxixyl. PHM-Revue Hortiole 292:37-. Reuveni, M., Sheglov, D., n Cohen, Y. (3): Control of moly-ore ey in pple fruits y β- minoutyri is n potssium phosphites. Plnt Dis. 87: Reuveni, M., Zhvi, T., n Cohen, Y. (1): Controlling owny milew (Plsmopr vitiol) in fiel-grown grpevine with β-minoutyri i (). Phytoprsiti 29: Stiher, L., Muh-Mni, B., n Metrux, J.P. (1997): Systemi quire resistne. Annu. Rev. Phytopthol. 35: Wlters, D., Wlsh, D., Newton, A., n Lyon, G. (5): Inue resistne for plnt isese ontrol: Mximizing the effiy of resistne eliitors. Phytopthology 95: