Mikrobiom šljive (Prunus domestica L.) i potencijal odabranih izolata za biokontrolu patogena šljive

Abstract

Šljiva (Prunus domestica L.) ima izuzetan značaj kao voćarska kultura u Srbiji i tradicionalno se prerađuje u rakiju šljivovicu. S obzirom da je godišnji prinos šljive ugrožen različitim bolestima, naročito izazivačima bakterioznog raka i mrke truleži neophodno je naći efikasne agense za njihovo suzbijanje, a naročito alternativu upotrebi hemijskih pesticida. U ovom radu je prvi put analiziran mikrobiom filosfere četiri sorte šljive (Čačanska lepotica, Čačanska rodna, Požegača i Ranka), obuhvatajući ranu (maj) i kasnu fenološku fazu (juli) razvića ploda. Indeksi alfa i beta diverziteta su pokazali da su zajednice bile heterogene i da je njihov sastav zavisio od sezone uzorkovanja i sorti šljive. U ukupnoj bakterijskoj zajednici je metagenomskim pristupom utvrđeno da su predstavnici razdela Proteobacteria bili najdominantniji, a najzastupljenije vrste su bile iz rodova: Methylobacterium, Sphingomonas i Hymenobacter. Tradicionalnim kultivabilnim pristupom i analizom sekvenci gena za 16S rRNK identifikovane su Pseudomonas syringae i Pseudomonas graminis kao najdominantnije vrste. Analiza mikobioma je ukazala na dominatnu zastupljenost predstavnika razdela Ascomycota. Vrste iz rodova Aureobasidium i Cryptococcus su bile najučestalije u maju, dok su u julu predstavnici različitih rodova dominirali na sortama šljive (Cryptococcus, Metschnikowia, Fusarium i Hanseniaspora). U okviru kolekcije kultivabilnih gljiva, identifikovano je 11 izolata Monilinia laxa na osnovu filogenetske analize sekvenci ITS regiona. Odabrani izolati M. laxa su prouzrokovali tipične simptome na ubranim plodovima sorti Požegača i Čačanska rodna, a testiranjem potencijalnih bakterijskih patogena su izdvojeni izolati P. syringae ČL2/2 i P7/16_2, koji su izazivali nekroze na ubranim listovima šljive svih ispitivanih sorti. Analizom antagonističkog potencijala kolekcije bakterija i kvasaca poreklom sa sve četiri sorte je izdvojen izolat Bacillus thuringiensis R3/3 sa snažnom antibakterijskom aktivnošću protiv autohtonih i referentnih fitopatogena...

Plum (Prunus domestica L.) has a great importance as a fruit crop in Serbia and it is traditionally processed into slivovitz brandy. Considering that the annual plum yield is significantly affected by various pathogens, especially those causing bacterial canker and brown rot, it is necessary to find effective agents for their control, and in particular, an alternative to the chemical pesticides. In this research, microbiome of four plum cultivars phyllosphere (Čačanska lepotica, Čačanska rodna, Požegača i Ranka) was analyzed for the first time, including the early (May) and late phenological stages (July) of fruit development. Alpha and beta diversity indices had shown that the communities were heterogenous and that their composition depended on sampling season and plum cultivars. The metagenomic approach revealed that the representatives of the phylum Proteobacteria were the most dominant in the total bacterial community, and that the most represented species were from the genera: Methylobacterium, Sphingomonas and Hymenobacter. Traditional cultivable approach and 16S rRNA sequence analyses identified Pseudomonas syringae i Pseudomonas graminis as two most dominant species. Mycobiome analysis revealed the dominance of the phylum Ascomycota representatives. Aureobasidium and Cryptococcus species were the most abundant in May, while in July representatives of different genera dominated the plum cultivars (Cryptococcus, Metschnikowia, Fusarium and Hanseniaspora). From the collection of cultivable fungi, eleven Monilinia laxa isolates were identified based on phylogenetic analysis of the ITS region sequences. The selected M. laxa isolates caused typical symptoms on the harvested fruits of the Požegača and Čačanska rodna cultivars, and the testing of potential bacterial pathogens revealed P. syringae ČL2/2 and P7/16_2 isolates, which caused necrosis on the harvested plum leaves of all tested cultivars. Antagonistic potential analysis of bacterial and yeast isolates from all four cultivars singled out Bacillus thuringiensis R3/3 with strong antibacterial activity against native and reference phytopathogens...