Monitoring, identification, and molecular-genetic characterization of phytopathogenic potato bacteria (Solanum tuberosum L.)

U Srbiji krompir ima veliki privredni značaj i pripada vodećim ratarsko-povrtarskim kulturama. Tokom monitoringa sprovedenog od 2015 do 2019. godine, obuhvaćeno je preko 2000 ha useva krompira sa 16 lokaliteta. Rezultati monitoringa su ukazali na prisustvo dve bakteriozne bolesti. Mrka trulež krtola krompira utvrđena je u 2015, 2016. i 2018. godini i kao uzročnik je identifikovana karantinska bakterija Ralstonia solanacearum. „Crna noga“ i vlažna trulež krtola krompira, koju su prouzrokovale bakterije Pectobacterium carotovorum, Pectobacterium brasiliense i Dickeya dianthicola, detektovana je u 2016, 2018. i 2019. godini. U ovom istraživanju, prisustvo P. brasiliense i D. dianthicola prvi put je zabeleženo na krompiru u Srbiji. Izolati R. solanacearum dobijeni iz 229 uzoraka sa mrkom truleži krtola bili su fenotipski homogeni, a na osnovu molekularno-genetičke karakterizacije svrstani su u filotip II. Rezultati ispitivanja fenotipskih karakteristika izolata iz 50 uzoraka sa crnom nogom i vlažnom truleži krtola ukazali su na postojanje uzročnika iz dva roda, Pectobacterium i Dickeya. Međutim, molekularno-genetička karakterizacija ovih izolata ukazala je na prisustvo tri vrste, pri čemu su P. brasiliense izolati bili heterogeni, dok su P. carotovorum i D. dianthicola izolati uglavnom bili homogeni. Metabarkoding analiza omogućila je uvid u sastav bakterijske mikrobijalne zajednice krtola krompira sa i bez simptoma vlažne truleži, kao i odgovarajućih zemljišta ukazujući da razvoj vlažne truleži nastaje zbog složenih interakcija između biljnih patogena i drugih endofitnih bakterija. Biokontrolna aktivnost Bacillus amyloliquefaciens sojeva SS-12.6 i SS-38.4 prema izolovanim fitopatogenim bakterijama je dokazana u in vitro, in situ i in planta uslovima.n Serbia, the potato has great economic importance and belongs to the leading crops. During the five-year monitoring (2015-2019), over 2000 ha of potato crops from 16 locations were observed. Monitoring results indicated the presence of two bacterial diseases. Brown rot of tubers was observed in 2015, 2016, and 2018, caused by the quarantine bacterium Ralstonia solanacearum. Blackleg and soft rot caused by the Pectobacterium carotovorum, P. brasiliense, and Dickeya dianthicola was observed in 2016, 2018, and 2019. In this study, P. brasiliense and D. dianthicola was recorded for the first time on the potato in Serbia. Isolates of R. solanacearum obtained from 229 samples with brown rot were phenotypically homogeneous, and based on molecular-genetic characterization they were classified into phylotype II. The results of testing the phenotypic characteristics of isolates from 50 samples with blackleg and soft rot indicated the presence of pathogens from two genera, Pectobacterium and Dickeya. However, molecular-genetic characterization of these isolates revealed the presence of three species, whereby P. brasiliense isolates were heterogeneous, while P. carotovorum and D. dianthicola isolates were mainly homogeneous. The metabarcoding analysis provided insight into the bacterial microbial community composition of potato tubers with and without soft rot symptoms, as well as the corresponding soils, indicating that the development of soft rot process arises due to complex interactions between plant pathogens and other endophytic bacteria. The biocontrol activity of Bacillus amyloliquefaciens strains SS-12.6 and SS-38.4 against isolated bacteria was proven in vitro, in situ, and in planta