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Soil-borne fungi belonging to the genus Rhizoctonia are considered to be among the most destructive sugar beet pathogens. Although multinucleate R. solani AG-2-2 is frequently detected as the main causal agent of root rot of sugar beet worldwide, several binucleate (AG-A, AG-E and AG-K) and multinucleate Rhizoctonia (R. solani AG-4, AG-5 and AG-8) have also been included in the disease complex. Due to their soil-borne nature and wide host range, the management of Rhizoctonia root rot of sugar beet is highly demanding. Identification of Rhizoctonia AG associated with root rot of sugar beet is the essential first step in determining a successful disease management strategy. In this paper we report a highly specific and sensitive real-time PCR protocol for detection of R. solani AG-2-2 which showed a high level of specificity after testing against 10 different anastomosis groups and subgroups, including AG-2-1 as the most closely related. Moreover, a similar conventional PCR assay showed the same specificity but proved to be at least a 100 times less sensitive. Future research will include further testing and adaptation of this protocol for direct detection and quantification of R. solani AG-2-2 in different substrates, including plant tissue and soil samples., Smatra se da su gljive iz roda Rhizoctonia koje se održavaju u zemljištu, najdestruktivniji patogeni šećerne repe. Mada je širom sveta višejedarna R. solani AG-2-2 najčešće označena kao najvažniji prouzrokovač truleži korena šećerne repe, nekoliko dvojedarnih (AG-A, AG-E i AG-K) kao i višejedarnih Rhizoctonia (R. solani AG-4, AG-5 i AG-8) takođe mogu da učestvuju u kompleksu bolesti. Kako se održavaju u zemljištu i imaju širok krug domaćina, suzbijanje vrsta Rhizoctonia koje izazivaju trulež korena šećerne repe veoma je zahtevno. Identifikacija anastomoznih grupa prouzrokovača oboljenja predstavlja neophodan prvi korak u uspostavljanju uspešnog suzbijanja. U ovom radu razvijen je visokospecifičan i osetljiv real-time PCR protokol za detekciju i identifikaciju R. solani AG-2-2 koji se pokazao kao visokospecifičan nakon testiranja koja su obuhvatila 10 različitih AG grupa i podgrupa, uključujući i AG-2-1 kao najsrodniju. Sličan konvencionalni PCR protokol ispoljio je istu specifičnost, ali i najmanje 100 × manju osetljivost. Buduća istraživanja uključiće dalje testiranje i adaptaciju ovog protokola za direktnu detekciju i kvantifikaciju R. solani AG-2-2 u različitim uzorcima, uključujući biljno tkivo i zemljište.

Strawberry production is a popular, fast-growing agricultural business in Serbia. Its cultivar selection has been changing fast, following market demands. One of the limiting factors of strawberry production worldwide is black root rot, primarily caused by binucleate Rhizoctonia. Recently, outbreaks of black root rot of strawberry have occurred in Serbia and the estimated disease incidence was up to 30%. Isolates of binucleate Rhizoctonia AG-A were recovered from symptomatic strawberry plants, and characterized on the bases of morphological, molecular and pathogenic features. Despite their uniform morphological characteristics, the isolates demonstrated genetic variability within ITS rDNA, grouping into three different phylogenetic sub-clusters which comprise AG-A isolates originating from Italy, Israel, Japan and the USA. The binucleate Rhizoctonia AG-A from Serbia exhibited uniform virulence on strawberry after inoculation of daughter plants and detached leaf petioles, as well as on seedlings of bean, carrot and sunflower, while they were non-pathogenic to wheat, maize, tomato, pepper, tobacco, cucumber, lettuce, peas, cabbage, rapeseed and sugar beet., Proizvodnja jagode je popularna grana poljoprivrede u Srbiji koja se brzo razvija. Sastav sorti uključenih u proizvodnju podleže stalnim promenama u skladu sa zahtevima tržišta. Jedan od ograničavajućih faktora u proizvodnji jagode širom sveta je crna trulež korena, bolest koju najčešće izazivaju dvojedarne vrste roda Rhizoctonia. U Srbiji je poslednjih godina nekoliko puta zabeležena pojava crne truleži jagode uz učestalost koja je iznosila do 30%. Iz biljaka jagode sa simptomima izdvojeni su izolati dvojedarne Rhizoctonia AG-A i okarakterisani na osnovu morfološih i molekularnih osobina i patogenosti. Uprkos uniformnim morfološkim osobinama, izolati su ispoljili genetičku varijabilnost na osnovu sekvence ITS rDNK, grupišući se u tri različita filogentska sub-klastera koji su obuhvatali isolate iz Italije, Izraela, Japana i SAD. Izolati dvojedarnih Rhizoctonia AG-A poreklom iz Srbije ispoljili su uniformnu virulentnost na jagodi nakon inokulacija živića i fragmenata lisnih peteljki, kao i na sejancima pasulja, mrkve i suncokreta, dok nisu bili patogeni za pšenicu, kukuruz, paradajz, papriku, duvan, krastavac, salatu, grašak, kupus i šećernu repu.

Antifungal activity of two essential oils, cinnamon (Cinnamomum verum J. Presl) and clove (Syzygium aromaticum (L.) Merrill & Perry), was evaluated against Cladobotryum dendroides (Bull.) W. Gams & Hooz, and Lecanicillium fungicola var. fungicola (Preuss) Hasebrauk, the causal agents of cobweb and dry bubble disease of cultivated mushroom. Inhibitory and fungicidal activity of the selected essential oils was assayed using three methods: microdilution, macrodilution fumigant and macrodilution contact method. Comparing all three methods, clove essential oil showed stronger activity than cinnamon against both fungi, having minimum inhibitory concentration (MIC) at the lowest concentrations tested (1.56, 0.02 and 0.1 µl ml-1, respectively). However, cinnamon oil was more toxic to L. fungicola var. fungicola then to C. dendroides in all three methods. Both oils exhibited stronger antifungal effects when used in the macrodilution fumigant than in contact method. The results showed that both cinnamon and clove essential oils have the potential for further in vivo experiments against L. fungicola var. fungicola and C. dendroides and indicated a possible use of these oils in integrated disease management in mushrooms., Ispitana je antifungalna aktivnost etarskih ulja cimeta i karanfilića prema Cladobotryum dendroides (Bull.) W. Gams & Hooz, i Lecanicillium fungicola var. fungicola (Preuss) Hasebrauk, prouzrokovačima paučinaste plesni i suve truleži šampinjona. Antifungalna aktivnost odabranih etarskih ulja testirana je primenom tri različite metode: mikrodilucione, makrodilucione fumigantne i makrodilucione kontaktne metode. Etarsko ulje karanfilića je ispoljilo jači efekat od ulja cimeta na obe gljive primenom sve tri metode, sa minimalnim inhibitornim koncentrecijama pri najnižim testiranim koncentracijama (1,56, 0,02 i 0,1 µl ml-1). Ulje cimeta je pokazalo veću toksičnost prema L. fungicola var. fungicola nego prema C. dendroides. Ispitivana etarska ulja ispoljila su jače antifungalno dejstvo primenjena fumigantno nego kontaktno u makrodilucionoj metodi. Antifungalno delovanje etarskih ulja cimeta i karanfilića in vitro, ukazuje na potencijal za dalja ispitivanja njihove efikasnosti in vivo, kao i mogućnosti uključivanja ovih etarskih ulja u integralnu zaštitu jestivih gljiva od bolesti prouzrokovanih mikopatogenim gljivama L. fungicola var. fungicola i C. dendroides.

Potted chrysanthemum plants (Chrysanthemum Indicum Groep, sin. Chr. x grandiflorum) originating from Mala Pruga, Zemun Polje, exhibited a variety of symptoms including stem and leaf necrosis, as well as bud and flower rot. Necrosis started on stems, which were previously cut in order to provoke flowering. Further on, necrosis spread and covered larger plant areas, and after a period of three weeks killed the plants. From diseased plants fungal isolates were obtained which proved to be pathogenic to healthy stems of chrysanthemum. According to macroscopic and microscopic as well as some biological properties the causal agent of chrysanthemum stem necrosis was identified as multinucleate Rhizoctonia sp. (Rhizoctonia solani)., Na saksijskim biljkama hrizanteme (Chrysanthemum Indicum Groep, sin. Chr. x grandiflorum) sa lokaliteta Mala Pruga, Zemun Polje, uočeni su simptomi u vidu sužavanja i nekroze stabljika, sušenja pupoljaka, cvetova i listova. Nekrotični proces započeo je na mestima gde su stabljike sečene u cilju provociranja obimnog cvetanja biljaka. Odatle, nekroza se širila da bi posle tri nedelje od pojave prvih simptoma zahvatila čitavu biljku. Iz obolelih stabljika izolovana je gljiva čija je patogenost potvrđena veštačkim inokulacijama zdravih stabljika hrizanteme. Na osnovu morfoloških (makroskopskih i mikroskopskih) i bioloških odlika, fitopatogena gljiva prouzrokovač nekroze hrizanteme, identifikovana je kao višejedarna Rhizoctonia sp.(Rhizoctonia solani).