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 Bakteriozno sušenje trešnje (Prunus avium L.) poslednjih nekoliko godina u mladim zasadima i plantažama trešnje predstavlja značajan problem u proizvodnji ove voćne vrste. Simptomi bolesti se ispoljavaju u vidu sušenja grana, grančica ili celih stabala, što se uglavnom zapaža na mestima rezidbe i oko pupoljaka, sa uočljivim promena boje tkiva kore, koje puca i nastaju rak rane. U periodu od 2012 – 2015 godine izvršen je monitoring zdravstvenog stanja trešnje kojim je obuhvaćeno nekoliko plantaža i manjih zasada trešnje iz više lokaliteta na području AP Vojvodine i centralne Srbije (Ritopek). Mlade voćke su očigledno najugroženije, jer smo na osnovu praćenja zdravstvenog stanja u više lokaliteta i zasadima različite starosti, pojavu bakterioznog sušenja u jačem ili slabijem intenzitetu, konstatovali samo u mladim zasadima (do 3 godine starosti – Selenča, Gornji Tavankut, Donji Tavankut, Ljutovo, Mikićevo i Kanjiža). Izolacijama na strandardne hranljive podloge, iz prikupljenih obolelih uzoraka trešnje, kao i sa zdravih pupoljaka i listova trešnje (epifitna populacija), dobijeni su brojni izolati bakterija P. syringae pvs. od kojih je za dalja ispitivanja odabrano 155 izolata. Identifikikacija dobijenih izolata je izvršena je na osnovu fenotipskih i genotipskih metoda. Na osnovu LOPAT testova izolati pripadaju Ia grupi fluorescentnih vrsta Pseudomonas syringae. Prema GATTa testovima utvrđene su dve grupe izolata u okviru vrste P. syringae: I grupa (G+A+T–Ta–) i II grupa (G–A–T+Ta+). Dodatni testovi su potvrdili GATTa testove, na osnovu kojih je zaključeno da sušenje mladih stabala trešnje prouzrokuju dve grupe bakterije P. s. pv. syringae (I grupa) i P. s. pv. morsprunorum rasa 1 (II grupa). Među ispitivanim izolatima nije bilo odstupanja u pogledu fenotipskih karakteristika u okviru iste grupe, osim sposobnosti stvaranja siringomicina pojedinih izolata I grupe (pv. syringae). Proverom patogenosti na raznim test biljkama i biljci domaćinu utvrđene su razlike, ali i određene sličnosti između izolata I i II grupe. Jasne razlike između grupa izolata utvrđene su pri inokulaciji zelenih plodova trešnje, višnje, ringlova i kruške, paradajza, paprike i mahuna boranije. Pri inokulaciji odvojenih listova jorgovana izolati I grupe (pv. syringae), kao i većina izolata II grupe (pv. morsprunorum rasa 1) su pozitivno reagovali, što ukazuje na heterogenost populacije bakterije P. s. pv. morsprunorum rasa 1. Pri inokulaciji sejanaca voćnih podloga (divlja trešnja, magriva, divlja šljiva, divlja kruška) svi izolati pv. syringae su prouzrokovali karakteristične patološke promene na podlogama svih voćnih vrsta, a izolati pv. morsprunorum rase 1 takođe na svim vrstama, osim na sejancima divlje šljive. Ovi rezultati ukazuju da je širenje bakterija moguće i putem podloga koje takođe mogu biti zaražene. Inokulacijama dvogodišnjih grančica trešnje u periodu mirovanja zaključeno je da su svi izolati pv. syringae i morprunorum rasa 1 podjednako patogeni na svim sortama trešnje (Burlat, Summit, Hedelfigenska i Germerzdorfska). Najveća dužina nekroze najčešće je zabeležena na sortama Burlat i Summit u kombinaciji sa izolatima I grupe (pv. syringae) u pojedinim slučajevima i sa izolatima II grupe (pv. morsprunorum rasa 1), a najmanja uglavnom kod sorti Germerzdorfska i Hedelfigenska sa izolatima II grupe (pv. morsprunorum rasa 1). Identifikacija izolata KBNS71 – 84 (Gornji Tavankut) i KBNS85 – 94 (Selenča) na bazi MLST korišćenjem gena gyrB, rpoD, gapA i gltA, jasno je pokazala prisustvo dva patovara P. s. pv. syringae i P. s. pv. morsprunorum rasa 1. Pri poređenju sa sojevima H – 1, V – 85, V – 88 (višnja) i V – 109 (trešnja) utvrđene su značajne razlike i postojanje genetskog diverziteta populacije ovih patogena. Simultana detekcija gena syrB i syrD utvrđena je kod 70 izolata I grupe (pv. syringae), a samo SyrB kod 9 izolata iste grupe (pv. syringae). Gen za sintezu koronatina detektovan je kod svih 76 izolata II grupe (pv. morsprunorum rasa 1). Rep – PCR metodom ustanovljene su značajne razlike (58%) između I i II grupe izolata (pv. syringae i pv. morsprunorum rasa 1). Ispitivani izolati sa trešnje u okviru pv. syringae nisu ispoljili međusobne razlike, ali se razlikuju od sojeva sa drugih lokaliteta i ranije izolovanih sa istog domaćina (V – 109 i T6), kao i od sojeva sa drugih domaćina – višnje (V – 85) i uljane tikve (Tk21) do 37%. Razlike među izolatima pv. morsprunorum rase 1 iznosile su manje od 5%, a 24% u odnosu na soj CFBP2119 istog patogenog varijeteta. Rep – PCR analiza ukazala je na nizak nivo heterogenosti ispitivanih izolata u okviru istog patogenog varijeteta. RAPD metoda, korišćenjem većeg broja prajmera, bila je uspešnija za poređenje ispitivanih izolata od rep – PCR. Od testiranih 11 prajmera, 4 (SPH1, DJP17, DJ15, DJ16) su selektovana za dalji rad na osnovu razlika među izolatima unutar patogenih varijeteta. Kumulativna RAPD analiza pokazala je da između ispitivanih izolata pv. syringae postoje razlike do 24%, a 41% u poređenju sa sojem KFB0103, dok su kod izolata pv. morsprunorum rase 1 razlike iznosile do 15%, a 36% u odnosu na soj 4 CFBP2119. Dobijeni rezultati RAPD analize ukazuju da u okviru populacije obe grupe ispitivanih izolata postoji određena heterogenost, ali je genetski diverzitet izraženiji kod pv. syringae. Proučavanjem epidemilogije ovih patogena u poljskim uslovima inokulacijom jednogodišnjih grana / mladara sortama Burlat, Germerzdorfska, Hedelfigenska i Droganova žuta, zaključeno je da trešnja u našim agroekološkim uslovima ranije postaje osetljiva (oktobar) prema P. s. pv. morsprunorum rasa 1 u odnosu na pv. syringae. Prvi pozitivni rezultati pri inokulaciji sojevima pv. syringae utvrđeni su pri inokulaciji u novembru. U pogledu dužine nekroze najuspešnije su bile novembarske inokulacije (najduže nekroze; 2,17 – 3,35 cm), uspešne su bile i januarske i martovske inokulacije, ali je dužina nekroze bila sve manja, respektivno. Generalno najduže nekroze su ostvarene kod sorte Burlat, a najkraće kod sorte Germerzdorfska. Sve inokulacije urađene u periodu vegetacije su bile negativne. Inokulacijama dvo – trogodišnjih grana na sorti Summit prve uspešne inokulacije (oba patovara) su ostvarene tek u novembru (oktobarske su bile negativne), kada je utvrđena i veća agresivnost patovara syringae. Pri inokulacijama u januaru dužina nekroze je bila manja, a martovska je bila negativna. Sve inokulacije vršene u periodu od bubrenja pupoljaka do opadanja lišća takođe su bile negativne. Ispitivanjem osetljivosti sotrimenta trešnje i pojedinih sorti višnje zaključeno je da su prema oba patovara (syringae i morsprunorum rasa 1) najosetljivije sorte trešnje Katalin, Linda, Summit, New Star i Burlat, srednje osetljive su sorte višnje Erdi Botermo i sorte trešnje Droganova žuta, CarmCarmen, Germerzdorfska i Rana od Noara, a slabo osetljive sorte višnje Španska i Ujfeheti firtoš i sorta trešnje Rita.Bacterial die back (canker) of sweet cherry (Prunus avium L.) in young orchards and sweet cherry plantations in the past few years has been a significant problem in the production of this fruit species. Symptoms of the disease were manifested in the form of drying branches, twigs or whole trees, which were mainly observed in places of pruning or around the buds, bark changes a color, cracks and cankers has formed. In the period 2012 - 2015 monitoring of the health status of sweet cherries was carried out covering several plantations and smaller orchards of sweet cherries in several localities in Vojvodina and central Serbia (Ritopek). Young fruit trees are obviously the most susceptible, based on monitoring of the health status in many localities and plantations of different ages, the occurrence of bacterial canker in a stronger or weaker intensity was found only in young plantations (up to 3 years old - Selenča, Gornji Tavankut, Donji Tavankut, Ljutovo, Mikićevo and Kanjiža). From collected diseased samples of sweet cherries, as well as healthy buds and leaves of sweet cherry (epiphytic population) isolations on standard nutrient medium, were obtained numerous isolates of P. syringae pvs. and for further investigations was selected 155 isolates. Identification of isolates was performed on the basis of phenotypic and genotypic methods. Based on LOPAT tests isolates belonging to Ia group fluorescent Pseudomonas syringae. According to GATTa tests two groups of P. syringae isolates were identified, I group (G+A+T-Ta-) and II group (G-A-T+Ta+). Additional tests confirmed the GATT tests, on the basis which it was concluded that the drying of young sweet cherry trees caused P. s. pv. syringae (I group) and P. s. pv. morsprunorum race 1 (II group). Among the tested isolates was not exceptions in phenotypic characteristics within the same group, except for the ability to produced syringomycine for some isolates of I groups (pv. syringae). In pathogenicity tests on various plants and host plant were observed differences, but also and some certain similarity between isolates of I and II groups. Clear differences between the groups of isolates were determined in the inoculations of green fruit of sweet cherry, sour cherry, cherry plum and pears, tomatoes, peppers and green bean pods. In the case of inoculation of separate lilac leaves isolates of I group (pv. syringae) and most isolates of II group (pv. morsprunorum race 1) reactions were positive, what indicating the heterogeneity of the population of P. s. pv. morsprunorum race 1. In the inoculation of fruit rootstock seedlings (wild cherry, Magriva, wild plum, wild pear) all isolates pv. syringae caused the characteristic pathological changes on the all fruit species, isolates of pv. morsprunorum race 1 also except on the seedlings of wild plum. These results suggest that the spreading of bacteria is possibly through the rootstock that can also be infected. Inoculations of two – years old branches of sweet cherry during dormancy, was concluded that all isolates pv. syringae and morprunorum race 1 were equally pathogenic in all sweet cherry cultivars (Burlat, Summit, Hedelfigen and Germersdorf). The longest length of necrosis usually was observed on the cultivars Burlat and Summit in combination with isolates of I groups (pv. syringae), in some cases with isolates of II group (pv. morsprunorum race 1), and the lowest mainly in cultivars Germersdorf and Hedelfigen with isolates of II group (pv. morsprunorum race 1). Identification of isolates KBNS71 - 84 (GornjiTavankut) and KBNS85 - 94 (Selenča) based on MLST using genes gyrB, rpoD, gapA and gltA genes clearly showed the presence of two patovars P. s. pv. syringae and P. s. pv. morsprunorum race 1. Comparison with strains H - 1, V - 85 V - 88 (sour cherry) and V - 109 (sweet cherry) showed significant differences and the existence of genetic diversity in the population of these pathogens. Simultaneous detection of syrB and syrD gene was found in 70 isolates of I group (pv. syringae) and only syrB gene in 9 isolates of the same group (pv. syringae). The gene for coronatine synthesis was detected in all 76 isolates of II group (pv. morsprunorum race 1). Rep - PCR method detected significant differences (58%) between isolates of I and II groups (pv. syringae and pv. morsprunorum race 1). The tested isolates from sweet cherry within pv. syringae did not show differences between them, but they were different from the strains from other locations and previously isolated from the same host (V - 109 and T6), as well as strains from other hosts - cherry (V - 85) and pumpkin (Tk21) to 37 %. The differences between isolates pv. morsprunorum race 1 were less than 5% and 24% compared to the same pathovar strain CFBP2119. Rep - PCR analysis indicated a low level of heterogeneity of isolates within the same pathovar. RAPD method using a large number of primers were more successful to compare isolates than rep - PCR. Among 11 tested primers, 4 (SPH1, DJP17, DJ15, DJ16) were selected for further work on the basis of the difference between isolates within same pathovar. Cumulative RAPD analysis showed up to 24% differences among tested isolates of pv. syringae and 41% compared to the strain KFB0103, while among isolates pv. morsprunorum race 1 differences were 15% and 36% compared to the strain CFBP2119. The results of RAPD analysis indicate that a certain heterogeneity 7 exists in the population of both tested groups of isolates, but genetic diversity is more pronounced among isolates of pv. syringae. Studying the epidemiology of this pathogen in field conditions, by inoculating one – year old branches / or shoots sweet cherry cultivars Burlat, Germersdorf, Hedelfigen and Droganova žuta, it was concluded that the sweet cherry in our agroecological conditions becoming sensitive (October) to P. s. pv. morsprunorum race 1 before in relation to the pv. syringae. The first positive results of inoculations with strains pv. syringae were determined in November. Regarding the length of necrosis most successful were inoculation in the November (necrosis longest; 2.17 to 3.35 cm), inoculations also were successful in the January and the March, but the length of necrosis was smaller, respectively. Generally longest necrosis were observed in the cultivar Burlat, and the shortest in cultivar Germersdorf. All inoculations carried out in the period of vegetation were negative. Inoculations of two – three – years old branches of the cultivar Summit, first successful inoculations (for both pathovar) were observed only in November (October was negative), when a greater aggressiveness of pathovar syringae were determined. In inoculations in January length of necrosis was smaller, and in March was negative. All inoculations carried out in the period from buds swelling to leaf falling were also negative. Investigation susceptibility of sweet cherry and some sour cherry cultivars was concluded that against to both pathovars (syringae and morsprunorum race 1) the most susceptible were cultivars of sweet cherry Katalin, Linda, Summit, New Star and Burlat, medium susceptible were cultivar of sour cherry Erdi Botermo and sweet cherry cultivars Droganova žuta, Carmen, Germersdorf and Rana od Noara and low susceptible cultivars of sour cherry Španska and Ujfeheti firtoš and cultivar of sweet cherry Rita

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 Bakteriozno sušenje trešnje (Prunus avium L.) poslednjih nekoliko godina u mladim zasadima i plantažama trešnje predstavlja značajan problem u proizvodnji ove voćne vrste. Simptomi bolesti se ispoljavaju u vidu sušenja grana, grančica ili celih stabala, što se uglavnom zapaža na mestima rezidbe i oko pupoljaka, sa uočljivim promena boje tkiva kore, koje puca i nastaju rak rane. U periodu od 2012 – 2015 godine izvršen je monitoring zdravstvenog stanja trešnje kojim je obuhvaćeno nekoliko plantaža i manjih zasada trešnje iz više lokaliteta na području AP Vojvodine i centralne Srbije (Ritopek). Mlade voćke su očigledno najugroženije, jer smo na osnovu praćenja zdravstvenog stanja u više lokaliteta i zasadima različite starosti, pojavu bakterioznog sušenja u jačem ili slabijem intenzitetu, konstatovali samo u mladim zasadima (do 3 godine starosti – Selenča, Gornji Tavankut, Donji Tavankut, Ljutovo, Mikićevo i Kanjiža). Izolacijama na strandardne hranljive podloge, iz prikupljenih obolelih uzoraka trešnje, kao i sa zdravih pupoljaka i listova trešnje (epifitna populacija), dobijeni su brojni izolati bakterija P. syringae pvs. od kojih je za dalja ispitivanja odabrano 155 izolata. Identifikikacija dobijenih izolata je izvršena je na osnovu fenotipskih i genotipskih metoda. Na osnovu LOPAT testova izolati pripadaju Ia grupi fluorescentnih vrsta Pseudomonas syringae. Prema GATTa testovima utvrđene su dve grupe izolata u okviru vrste P. syringae: I grupa (G+A+T–Ta–) i II grupa (G–A–T+Ta+). Dodatni testovi su potvrdili GATTa testove, na osnovu kojih je zaključeno da sušenje mladih stabala trešnje prouzrokuju dve grupe bakterije P. s. pv. syringae (I grupa) i P. s. pv. morsprunorum rasa 1 (II grupa). Među ispitivanim izolatima nije bilo odstupanja u pogledu fenotipskih karakteristika u okviru iste grupe, osim sposobnosti stvaranja siringomicina pojedinih izolata I grupe (pv. syringae). Proverom patogenosti na raznim test biljkama i biljci domaćinu utvrđene su razlike, ali i određene sličnosti između izolata I i II grupe. Jasne razlike između grupa izolata utvrđene su pri inokulaciji zelenih plodova trešnje, višnje, ringlova i kruške, paradajza, paprike i mahuna boranije. Pri inokulaciji odvojenih listova jorgovana izolati I grupe (pv. syringae), kao i većina izolata II grupe (pv. morsprunorum rasa 1) su pozitivno reagovali, što ukazuje na heterogenost populacije bakterije P. s. pv. morsprunorum rasa 1. Pri inokulaciji sejanaca voćnih podloga (divlja trešnja, magriva, divlja šljiva, divlja kruška) svi izolati pv. syringae su prouzrokovali karakteristične patološke promene na podlogama svih voćnih vrsta, a izolati pv. morsprunorum rase 1 takođe na svim vrstama, osim na sejancima divlje šljive. Ovi rezultati ukazuju da je širenje bakterija moguće i putem podloga koje takođe mogu biti zaražene. Inokulacijama dvogodišnjih grančica trešnje u periodu mirovanja zaključeno je da su svi izolati pv. syringae i morprunorum rasa 1 podjednako patogeni na svim sortama trešnje (Burlat, Summit, Hedelfigenska i Germerzdorfska). Najveća dužina nekroze najčešće je zabeležena na sortama Burlat i Summit u kombinaciji sa izolatima I grupe (pv. syringae) u pojedinim slučajevima i sa izolatima II grupe (pv. morsprunorum rasa 1), a najmanja uglavnom kod sorti Germerzdorfska i Hedelfigenska sa izolatima II grupe (pv. morsprunorum rasa 1). Identifikacija izolata KBNS71 – 84 (Gornji Tavankut) i KBNS85 – 94 (Selenča) na bazi MLST korišćenjem gena gyrB, rpoD, gapA i gltA, jasno je pokazala prisustvo dva patovara P. s. pv. syringae i P. s. pv. morsprunorum rasa 1. Pri poređenju sa sojevima H – 1, V – 85, V – 88 (višnja) i V – 109 (trešnja) utvrđene su značajne razlike i postojanje genetskog diverziteta populacije ovih patogena. Simultana detekcija gena syrB i syrD utvrđena je kod 70 izolata I grupe (pv. syringae), a samo SyrB kod 9 izolata iste grupe (pv. syringae). Gen za sintezu koronatina detektovan je kod svih 76 izolata II grupe (pv. morsprunorum rasa 1). Rep – PCR metodom ustanovljene su značajne razlike (58%) između I i II grupe izolata (pv. syringae i pv. morsprunorum rasa 1). Ispitivani izolati sa trešnje u okviru pv. syringae nisu ispoljili međusobne razlike, ali se razlikuju od sojeva sa drugih lokaliteta i ranije izolovanih sa istog domaćina (V – 109 i T6), kao i od sojeva sa drugih domaćina – višnje (V – 85) i uljane tikve (Tk21) do 37%. Razlike među izolatima pv. morsprunorum rase 1 iznosile su manje od 5%, a 24% u odnosu na soj CFBP2119 istog patogenog varijeteta. Rep – PCR analiza ukazala je na nizak nivo heterogenosti ispitivanih izolata u okviru istog patogenog varijeteta. RAPD metoda, korišćenjem većeg broja prajmera, bila je uspešnija za poređenje ispitivanih izolata od rep – PCR. Od testiranih 11 prajmera, 4 (SPH1, DJP17, DJ15, DJ16) su selektovana za dalji rad na osnovu razlika među izolatima unutar patogenih varijeteta. Kumulativna RAPD analiza pokazala je da između ispitivanih izolata pv. syringae postoje razlike do 24%, a 41% u poređenju sa sojem KFB0103, dok su kod izolata pv. morsprunorum rase 1 razlike iznosile do 15%, a 36% u odnosu na soj 4 CFBP2119. Dobijeni rezultati RAPD analize ukazuju da u okviru populacije obe grupe ispitivanih izolata postoji određena heterogenost, ali je genetski diverzitet izraženiji kod pv. syringae. Proučavanjem epidemilogije ovih patogena u poljskim uslovima inokulacijom jednogodišnjih grana / mladara sortama Burlat, Germerzdorfska, Hedelfigenska i Droganova žuta, zaključeno je da trešnja u našim agroekološkim uslovima ranije postaje osetljiva (oktobar) prema P. s. pv. morsprunorum rasa 1 u odnosu na pv. syringae. Prvi pozitivni rezultati pri inokulaciji sojevima pv. syringae utvrđeni su pri inokulaciji u novembru. U pogledu dužine nekroze najuspešnije su bile novembarske inokulacije (najduže nekroze; 2,17 – 3,35 cm), uspešne su bile i januarske i martovske inokulacije, ali je dužina nekroze bila sve manja, respektivno. Generalno najduže nekroze su ostvarene kod sorte Burlat, a najkraće kod sorte Germerzdorfska. Sve inokulacije urađene u periodu vegetacije su bile negativne. Inokulacijama dvo – trogodišnjih grana na sorti Summit prve uspešne inokulacije (oba patovara) su ostvarene tek u novembru (oktobarske su bile negativne), kada je utvrđena i veća agresivnost patovara syringae. Pri inokulacijama u januaru dužina nekroze je bila manja, a martovska je bila negativna. Sve inokulacije vršene u periodu od bubrenja pupoljaka do opadanja lišća takođe su bile negativne. Ispitivanjem osetljivosti sotrimenta trešnje i pojedinih sorti višnje zaključeno je da su prema oba patovara (syringae i morsprunorum rasa 1) najosetljivije sorte trešnje Katalin, Linda, Summit, New Star i Burlat, srednje osetljive su sorte višnje Erdi Botermo i sorte trešnje Droganova žuta, CarmCarmen, Germerzdorfska i Rana od Noara, a slabo osetljive sorte višnje Španska i Ujfeheti firtoš i sorta trešnje Rita.Bacterial die back (canker) of sweet cherry (Prunus avium L.) in young orchards and sweet cherry plantations in the past few years has been a significant problem in the production of this fruit species. Symptoms of the disease were manifested in the form of drying branches, twigs or whole trees, which were mainly observed in places of pruning or around the buds, bark changes a color, cracks and cankers has formed. In the period 2012 - 2015 monitoring of the health status of sweet cherries was carried out covering several plantations and smaller orchards of sweet cherries in several localities in Vojvodina and central Serbia (Ritopek). Young fruit trees are obviously the most susceptible, based on monitoring of the health status in many localities and plantations of different ages, the occurrence of bacterial canker in a stronger or weaker intensity was found only in young plantations (up to 3 years old - Selenča, Gornji Tavankut, Donji Tavankut, Ljutovo, Mikićevo and Kanjiža). From collected diseased samples of sweet cherries, as well as healthy buds and leaves of sweet cherry (epiphytic population) isolations on standard nutrient medium, were obtained numerous isolates of P. syringae pvs. and for further investigations was selected 155 isolates. Identification of isolates was performed on the basis of phenotypic and genotypic methods. Based on LOPAT tests isolates belonging to Ia group fluorescent Pseudomonas syringae. According to GATTa tests two groups of P. syringae isolates were identified, I group (G+A+T-Ta-) and II group (G-A-T+Ta+). Additional tests confirmed the GATT tests, on the basis which it was concluded that the drying of young sweet cherry trees caused P. s. pv. syringae (I group) and P. s. pv. morsprunorum race 1 (II group). Among the tested isolates was not exceptions in phenotypic characteristics within the same group, except for the ability to produced syringomycine for some isolates of I groups (pv. syringae). In pathogenicity tests on various plants and host plant were observed differences, but also and some certain similarity between isolates of I and II groups. Clear differences between the groups of isolates were determined in the inoculations of green fruit of sweet cherry, sour cherry, cherry plum and pears, tomatoes, peppers and green bean pods. In the case of inoculation of separate lilac leaves isolates of I group (pv. syringae) and most isolates of II group (pv. morsprunorum race 1) reactions were positive, what indicating the heterogeneity of the population of P. s. pv. morsprunorum race 1. In the inoculation of fruit rootstock seedlings (wild cherry, Magriva, wild plum, wild pear) all isolates pv. syringae caused the characteristic pathological changes on the all fruit species, isolates of pv. morsprunorum race 1 also except on the seedlings of wild plum. These results suggest that the spreading of bacteria is possibly through the rootstock that can also be infected. Inoculations of two – years old branches of sweet cherry during dormancy, was concluded that all isolates pv. syringae and morprunorum race 1 were equally pathogenic in all sweet cherry cultivars (Burlat, Summit, Hedelfigen and Germersdorf). The longest length of necrosis usually was observed on the cultivars Burlat and Summit in combination with isolates of I groups (pv. syringae), in some cases with isolates of II group (pv. morsprunorum race 1), and the lowest mainly in cultivars Germersdorf and Hedelfigen with isolates of II group (pv. morsprunorum race 1). Identification of isolates KBNS71 - 84 (GornjiTavankut) and KBNS85 - 94 (Selenča) based on MLST using genes gyrB, rpoD, gapA and gltA genes clearly showed the presence of two patovars P. s. pv. syringae and P. s. pv. morsprunorum race 1. Comparison with strains H - 1, V - 85 V - 88 (sour cherry) and V - 109 (sweet cherry) showed significant differences and the existence of genetic diversity in the population of these pathogens. Simultaneous detection of syrB and syrD gene was found in 70 isolates of I group (pv. syringae) and only syrB gene in 9 isolates of the same group (pv. syringae). The gene for coronatine synthesis was detected in all 76 isolates of II group (pv. morsprunorum race 1). Rep - PCR method detected significant differences (58%) between isolates of I and II groups (pv. syringae and pv. morsprunorum race 1). The tested isolates from sweet cherry within pv. syringae did not show differences between them, but they were different from the strains from other locations and previously isolated from the same host (V - 109 and T6), as well as strains from other hosts - cherry (V - 85) and pumpkin (Tk21) to 37 %. The differences between isolates pv. morsprunorum race 1 were less than 5% and 24% compared to the same pathovar strain CFBP2119. Rep - PCR analysis indicated a low level of heterogeneity of isolates within the same pathovar. RAPD method using a large number of primers were more successful to compare isolates than rep - PCR. Among 11 tested primers, 4 (SPH1, DJP17, DJ15, DJ16) were selected for further work on the basis of the difference between isolates within same pathovar. Cumulative RAPD analysis showed up to 24% differences among tested isolates of pv. syringae and 41% compared to the strain KFB0103, while among isolates pv. morsprunorum race 1 differences were 15% and 36% compared to the strain CFBP2119. The results of RAPD analysis indicate that a certain heterogeneity 7 exists in the population of both tested groups of isolates, but genetic diversity is more pronounced among isolates of pv. syringae. Studying the epidemiology of this pathogen in field conditions, by inoculating one – year old branches / or shoots sweet cherry cultivars Burlat, Germersdorf, Hedelfigen and Droganova žuta, it was concluded that the sweet cherry in our agroecological conditions becoming sensitive (October) to P. s. pv. morsprunorum race 1 before in relation to the pv. syringae. The first positive results of inoculations with strains pv. syringae were determined in November. Regarding the length of necrosis most successful were inoculation in the November (necrosis longest; 2.17 to 3.35 cm), inoculations also were successful in the January and the March, but the length of necrosis was smaller, respectively. Generally longest necrosis were observed in the cultivar Burlat, and the shortest in cultivar Germersdorf. All inoculations carried out in the period of vegetation were negative. Inoculations of two – three – years old branches of the cultivar Summit, first successful inoculations (for both pathovar) were observed only in November (October was negative), when a greater aggressiveness of pathovar syringae were determined. In inoculations in January length of necrosis was smaller, and in March was negative. All inoculations carried out in the period from buds swelling to leaf falling were also negative. Investigation susceptibility of sweet cherry and some sour cherry cultivars was concluded that against to both pathovars (syringae and morsprunorum race 1) the most susceptible were cultivars of sweet cherry Katalin, Linda, Summit, New Star and Burlat, medium susceptible were cultivar of sour cherry Erdi Botermo and sweet cherry cultivars Droganova žuta, Carmen, Germersdorf and Rana od Noara and low susceptible cultivars of sour cherry Španska and Ujfeheti firtoš and cultivar of sweet cherry Rita

Patogeni lista trešnje i višnje u Srbiji

In recent years, sweet and sour cherry production in Serbia has increased. Under Serbian agroecological conditions, pathogens causing leaf diseases threaten the success of sweet and sour cherry production. In the period 2012-2019, the health status of cherries was monitored in more than 30 locations. Depending on the production system, the following leaf pathogens were identified: Blumeriella jaapii, Wilsonomyces carpophilus, Mycosphaerella cerasella, Phoma prunicola, Podosphaera clandestina and Pseudomonas syringae pv. syringae and morsprunorum race 1. Leaf pathogens caused premature defoliation, which adversely affected bud formation for the next growing season and increased susceptibility to freezing. Therefore, attention should be focused on correct leaf pathogen identification, and proper selection, application and rotation of fungicides.Poslednjih godina proizvodnja trešnje i višnje u Srbiji je povećana. U našim agroekološkim uslovima, patogeni lista ugrožavaju proizvodnju ovih perspektivnih voćnih vrsta. U periodu 2012-2019. godine praćeno je zdravstveno stanje trešnje i višnje, na više od 30 lokaliteta. avisno od sistema proizvodnje identifikovani su sledeći patogeni lista: Blumeriella jaapii, Wilsonomyces carpophilus, Mycosphaerella cerasella, Phoma prunicola, Podosphaera clandestina, Pseudomonas siringae pv. syringae i morsprunorum rasa 1. Patogeni lista izazivaju prevremenu defolijaciju, što negativno utiče na formiranje pupoljaka za narednu vegetaciju i povećanu osetljivost na izmrzavanje. Stoga pažnju treba usmeriti na ispravnu identifikaciju patogena, pravilan izbor i rotaciju fungicida različitog mehanizma delovanja, kao i optimalno vreme za njihovu primenu

Survey of apple collar and rootstock blight in Serbia

Apple production in Serbia is characterized by the introduction of new technologies and the establishment of intensive plantations based on modern systems. In intensive apple production systems, sudden and rapid decay of young apple trees exhibiting collar and rootstock blight symptoms in the first few years after planting is becoming a prevalent issue. However, knip or nursery trees with lateral branches (feathers) on rootstock M.9 i.e. oneto five-year old are most seriously affected. Based on a longitudinal survey of young apple plantations in Serbia and the results of pathogen detection and identification using conventional and molecular methods, the plant pathogenic bacterium Erwinia amylovora was found as the causative agent. By increasing the incidence of collar and rootstock blight in young apple trees, E. amylovora is gaining importance as the most destructive disease in apple production. In order to control E. amylovora effectively and apply appropriate control measures, it is necessary to survey the development of lesser-known symptoms caused by this pathogen, which are becoming prevalent in Serbian agroecological conditions

Alelski profil izolata Xanthomonas campestris pv. campestris sa kupusa u Srbiji

Xanthomonas campestris pv. campestris (Xcc), the causal agent of black rot disease of cabbage (Brassica oleracea var. capitata L.), is one of the most important bacteria which affect proper cabbage growth, leading to head weight and quality losses and thereby drastically reducing its marketing value. The pathogen is genetically diverse, which is evident from the presence of eleven races worldwide and more than thirty combinations of allelic profiles. Therefore, this study aimed to determine the allelic profiles of Serbian cabbage Xcc strains obtained in 2014. The analysis was done on three selected Xcc strains whose DNA was first amplified using polymerase chain reaction (PCR) with four housekeeping genes - P-XdnaK, fyuA, gyrB, and rpoD, then sequenced, and the obtained sequences were finally used to determine allelic profiles. Allelic profiles were determined by comparison with 33 Xcc strains obtained from different hosts and regions, whose allelic profiles had been determined previously. A non-redundant database (NRDB) from the pubMLST was used for allelic profile determination and Phyloviz software for constructing a minimum spanning tree. The obtained allelic profile of all Serbian Xcc cabbage strains was 1, 3, 1, 1 for the P-X-dnaK, fyuA, gyrB and rpoD genes, respectively. This profile is assigned as sequence type 2 (ST2) and it coincides with a Portuguese B. oleracea Xcc strain, CPBF 213, originating from B. oleracea var. costata. No connection between sequence type (ST) and the host was detected.Xanthomonas campestris pv. campestris (Xcc), prouzrokovač crne truleži kupusa (Brassica oleracea var. capitata L.) svrstava se među najvažnije fitopatogene bakterije koje utiču na pravilno razviće kupusa, dovodeći do gubitka težine glavice i njenog kvaliteta i na taj način drastično smanjuje njegovu ekonomsku vrednost. Ovaj patogen je genetički heterogen, što se ogleda kroz prisustvo dokazanih jedanaest rasa i više od trideset kombinacija alelskih profila širom sveta. Zbog svega navedenog, cilj ovog rada je determinacija alelskih profila Xcc sojeva poreklom sa kupusa prikupljenih 2014. godine. Analiza je vršena kod tri reprezentativna Xcc soja čija je DNK amplifikovana primenom lančane reakcije polimeraze (PCR) sa četiri konzervativna gena - dnaK, fyuA, gyrB i rpoD, a zatim sekvencirana i korišćena za determinaciju alelskih profila. Alelski profili su određivani poređenjem sa 33 Xcc soja izolovana sa različitih domaćina i regiona, čiji su alelski profili prethodno utvrđeni. Nonredundant baza podataka (NRDB) od pubMLST je korišćena za determinaciju alaleskih profila, a Phyloviz softver za konstrukciju Minimum Spanning stabla. Dobijeni alelski profil za sve Xcc sojeve sa kupusa iz Srbije je 1, 3, 1, 1 za gene dnaK, fyuA, gyrB i rpoD, redom. Ovaj profil je označen kao tip sekvence 2 (ST2) i podudara se sa portugalskim B. oleracea Xcc sojem CPBF 213 poreklom sa B. oleracea var. costata. Veza između tipa sekvence (ST) i biljke domaćina nije pronađena

Uticaj klimatskih promjena na pojavu bolesti štetočina poljoprivrednih biljaka i šumskog drveća

Uticaji klimatskih promjena na štetne organizme su složeni iz razloga što i drugi faktori koji utiču na njih nisu konstantni već se mijenjaju. I pored toga, klimatske promjene mogu na slične ili različite načine uticati na razne prouzrokovače biljnih bolesti i štetočine, u zavisnosti kojoj grupi organizama oni pripadaju: gljivama, bakterijama, virusima, insektima, nematodama i slično. Кod fitopatogenih gljiva ovi uticaji mogu se ispoljiti u pogledu: promjene biologije; brže evolucije zbog dužeg godišnjeg doba; pojave novih rasa ili veće agresivnosti postojećih vrsta zbog rekombinacije gena; mijenjanja geografske rasprostranjenosti, bilo prema sjevernoj hemisferi ili na područja sa višom nadmorskom visinom; introdukcije karantinskih i invazivnih vrsta, kao i širenja u nova područja u odnosu na područje porijekla; veću produkciju mikotoksina i dr. Za viruse i bakterije koji se prenose vektorima od posebnog značaja je uticaj klimatskih promjena na prisustvo, širenje i brojnost vektora. Pozitivan uticaj klimatskih promjena na različite štetočine biljaka može se ispoljiti u vidu: promjene biologije i pojave većeg broja generacija; povećane brojnosti i plodnosti; boljeg prezimljavanja; proširenog kruga domaćina; introdukcije karantinskih i invazivnih vrsta; širenja u nova područja i drugo. Pozitivni uticaji klimatskih promjena na štetne organizme najčešće su sa negativnim efektom na razvoj poljoprivrede i proizvodnju hrane, razvoj šumarstva, biodiverzitet i životnu sredinu – zbog mogućnosti nastanka većih ekonomskih šteta, kao i većih potreba za primjenom pesticida. Кlimatske promjene, takođe, mogu uticati i na biljke domaćine, pri čemu je od posebnog značaja njihov gubitak prirodne osnove otpornosti. Iako je došlo do napretka u praćenju i razumijevanju klimatskih promjena, ostaju potrebe za mnogim naučnim, tehničkim i institucionalnim rješenjima za precizno planiranje, prilagođavanje i ublažavanje efekata klimatskih promjena na prouzrokovače biljnih bolesti i štetočine, kao i biljke domaćine i njihove interakcije

Epidemiology studies of Pseudomonas syringae pathovars associated with bacterial canker on the sweet cherry in Serbia

This study was conducted to examine the epidemiological characteristics of two Pseudomonas syringae pvs. – syringae (Pss) and morsprunorum race 1 (Psm) on the sweet cherry in both field and laboratory conditions. Cycled inoculations of one-year-old branches indicated that the sweet cherry became sensitive to Psm race 1 earlier in the season (October) compared to Pss (November). The most severe infections occurred in the dormancy period (November), while the necroses formed in January and March were less in their length. Inoculations of the two-/three-year-old branches performed in November resulted in necrosis, with those induced by Pss being more aggressive. The January inoculations, however, resulted in less formed necroses in length. Laboratory tests performed on excised sweet cherry branches confirmed the results yielded by the field experiments, indicating that the dormancy period poses the greatest risk for the P. syringae pvs. infection. The isolation of Pss and Psm bacteria from naturally infected sweet cherry samples (cankers) during the summer indicated that the bacteria that persists in cankers in low numbers became active during autumn. Significant Pss and Psm race 1 epiphytic bacterial populations were noted during the spring, but decreased in the summer and increased again in the autumn, indicating the presence of inoculum reservoirs. The greater understanding of the control strategies aimed at the epidemiological factors should, thus, facilitate better disease outbreak management

GENETIC INSIGHT INTO THE ISOLATES CAUSING BLACKLEG DISEASE ON POTATO

Blackleg disease, caused by pectolytic bacteria from genus Dickeya and Pectobacterium is currently being one of the main concerns in potato production. Yield loss and reduced quality, visible through potato black rotting at the stem base, as well as whole plant decaying, makes potato cultivation less profitable. Blackleg disease outbreak was observed in potato field (cv. Lady Claire) in Bačka (northern Serbia) in June 2018. The percent of the infected plants, estimated during the vegetation season was 45%, with yield reduction of about 20%. In this study the causal pathogens were genetically characterized using multilocus sequence analysis (MLSA). DNA of the obtained isolates was amplified with primers made based on the sequences of five housekeeping genes - gapA, icdA, mdh, pgi and proA and sequenced. Phylogenetic analysis was performed to compare the obtained isolates with the ones already deposited in NCBI database. NCBI BLAST identified isolates as Dickeya dianthicola and Pectobacterium carotovorum subsp. brasiliensis, indicating on the persistence of mix infection on observed potato crop. According to all genes, isolates appeared to be the most similar (99-100%) to the reference strains - D. dianthicola (CFBP 1200) and P. carotovorum subsp. brasiliensis (BC1). Blast results were confirmed after phylogenetic analysis, where isolates of both identified species were clustering with the rest of the strains of the same species, obtained from NCBI. Our findings confirm the presence of new blackleg causal agents, D. dianthicola and P. carotovorum subsp. brasiliensis on potato in Serbia. Their isolation and localization is of great importance, especially D. dianthicola which has quarantine status, and therefore it gives a signal for pathogen eradication and prevention of its future spreading

Toxin production by pseudomonas syringae pathovars originating from sweet scherry

Pseudomonas syringae pathovars syringae and morsprunorum race 1, causal agents of sweet cherry die back were investigated for their toxin production. Total of 155 strains isolated from diseases sweet cherries from several location in Vojvodina Province, Serbia were used. In previous study the strains were identified as a pv. syringae(79 strains, based on presence/absence of syrB and syrD genes) and as a pv. morsprunorum race 1 (76, presence cflgene)based on molecular identification.In this study, bioassay for syringomycin production showed that 64 strainsamong pv. syringaeproduced toxin, and 15 have not in the presence of syringomycin sensitive organismsG. candidum,S. cerevisiaeand R. pilimanae. However, using bioassay for coronatine production on the potato slices only few strains out of 76 pv. morsprunorum race 1 strains produced coronatine

GENETIC INSIGHT INTO THE ISOLATES CAUSING BLACKLEG DISEASE ON POTATO

Blackleg disease, caused by pectolytic bacteria from genus Dickeya and Pectobacterium is currently being one of the main concerns in potato production. Yield loss and reduced quality, visible through potato black rotting at the stem base, as well as whole plant decaying, makes potato cultivation less profitable. Blackleg disease outbreak was observed in potato field (cv. Lady Claire) in Bačka (northern Serbia) in June 2018. The percent of the infected plants, estimated during the vegetation season was 45%, with yield reduction of about 20%. In this study the causal pathogens were genetically characterized using multilocus sequence analysis (MLSA). DNA of the obtained isolates was amplified with primers made based on the sequences of five housekeeping genes - gapA, icdA, mdh, pgi and proA and sequenced. Phylogenetic analysis was performed to compare the obtained isolates with the ones already deposited in NCBI database. NCBI BLAST identified isolates as Dickeya dianthicola and Pectobacterium carotovorum subsp. brasiliensis, indicating on the persistence of mix infection on observed potato crop. According to all genes, isolates appeared to be the most similar (99-100%) to the reference strains - D. dianthicola (CFBP 1200) and P. carotovorum subsp. brasiliensis (BC1). Blast results were confirmed after phylogenetic analysis, where isolates of both identified species were clustering with the rest of the strains of the same species, obtained from NCBI. Our findings confirm the presence of new blackleg causal agents, D. dianthicola and P. carotovorum subsp. brasiliensis on potato in Serbia. Their isolation and localization is of great importance, especially D. dianthicola which has quarantine status, and therefore it gives a signal for pathogen eradication and prevention of its future spreading