BIODIVERSITAS ISSN: 1412-033X Volume 22, Number 6, June 2021 E-ISSN: 2085-4722 Pages: 3229-3236 DOI: 10.13057/biodiv/d220626 The potential of endophytic bacteria isolated from Tagetes sp. to control Meloidogyne spp. infection on tomato plants ABDUL MUNIF 1,♥ , MUHAMMAD NURSALIM 1 , ANKARDIANSYAH PANDU PRADANA 2 1 Department of Plant Protection, Faculty of Agriculture, Institut Pertanian Bogor. Jl. Meranti, IPB Dramaga Campus, Bogor 16680, West Java, Indonesia. Tel./fax.: +62-251-8629353, ♥ email: abdulmunif@ipb.ac.id 2 Department of Plant Protection, Faculty of Agriculture, Universitas Jember. Jl. Kalimantan No. 37, Tegalboto Campus, Jember 68121, East Java, Indonesia Manuscript received: 17 March 2021. Revision accepted: 18 May 2021. Abstract. Munif A, Nursalim M, Pradana AP. 2021. The potential of endophytic bacteria isolated from Tagetes sp. to control Meloidogyne spp. infection on tomato plants. Biodiversitas 22: 3229-3236. The root-knot nematode (Meloidogyne spp.) is one of the plant-parasitic nematodes that cause economical loss in the vegetable plantations in the world. The endophytic bacteria may act as a potential biological agent to control the plant-parasitic nematodes. The aim of this study was to explore the endophytic bacteria from Tagetes sp., which had a potential to control Meloidogyne spp. and act as growth promoter for tomato plants. The endophytic bacteria were isolated from the roots and stems of Tagetes sp. and tissues were cultured on the tryptic soy agar (TSA) media. The endophytic bacterial isolates were selected using hypersensitive and blood agar tests to identify their biological safety. The selected endophytic bacteria were also assessed for growth promoter test in the tomato plants. The selected endophytic bacteria were assessed in vitro against the Meloidogyne spp. juvenile 2 and their effectiveness in suppressing the root-knot nematodes on tomato plants in greenhouse. The results showed that total of 184 endophytic bacterial isolates were successfully isolated from the roots and stem of Tagetes sp. In hypersensitive and hemolytic tests, 78 and 36 isolates showed negative responses, respectively. Of the 36 isolates tested, it was found that 14 of them were able to promote the growth of tomato seedlings. In in vitro test, 14 endophytic bacteria showed 73-93% mortality rate of Meloidogyne spp J2. The results at greenhouse showed that 3 bacterial isolates, namely, AL21, AL44, and AL53 suppress the number of root-knot nematodes up to 50-74% and improve tomato plant growth by 32%. These results indicate that endophytic bacteria isolated from Tagetes sp. have the potential to act as biocontrol agents of parasitic nematodes and a plant growth promoter. Keywords: Biocontrol, Meloidogyne, mortality, secondary metabolites, Tagetes INTRODUCTION The root-knot nematode (Meloidogyne spp.) is one of the plant-parasitic nematodes causing economical loss in vegetable plantations in the world. The agricultural yield loss around the world due to plant-parasitic nematodes reached 100 billion US dollars (Elling 2013). The estimation of yield loss in tropical plants such as eggplants was 17% -20%, melon 18% -33%, and tomatoes 23% - 38% (Luc et al. 2005). Ralmi et al. (2016) reported that worldwide yield loss due to root-knot nematodes on potato reached 15% and in vegetables, it was 50-80%. Symptoms are difficult to diagnose due to the attack of Meloidogyne spp. on the soil surface and plants usually show stunted growth, yellowing, and wilting in less water conditions (Subedi et al. 2020). These damages will commonly inhibit the water and nutrient absorptions, and translocation. The secondary infection by other pathogens causes rotting symptom spread from the nematode infection (Singh et al. 2019). Nematode control can be attempted using chemical nematicides, resistant variety, land sanitation, liming in the infested land, plant rotation, uprooting the infested plant, and by biological control (Ralmi et al. 2016). The nematode control found often uses chemical materials. The excessive use of chemical materials creates a new environment for the plant pathogens, due to which they become resistant (Ntalli and Caboni 2012). Furthermore, the chemical materials can interfere with the beneficial microbes and human health (Kalliora et al. 2018). The control strategy of nematode plant-parasitic is focused on environmental safety and sustainable methods (Ralmi et al. 2016). One of the alternative controls used in agricultural practices is nematocidal antagonistic plants. One of the antagonistic plants used as the nematode controller is Tagetes sp (Marahatta et al. 2012; Hanawi 2016). Tagetes sp. usually used as an alternative crop in crop rotation systems. In addition, some parts of this plant can also be used as raw materials for green organic fertilizer (Stroze et al. 2019). The secondary metabolites found in Tagetes sp. are triterpenoids, steroids, alkaloids, carotenoids, skeleton carbons, thiophene derivatives, benzofuran derivatives, and others. Several compounds found in Tagetes act as herbal medicine, insecticide, and fungicide (Verma and Verma 2012; Xu et al. 2012; Shetty et al. 2015). The capability of Tagetes sp. in controlling the plant-parasitic nematodes is not only due to its secondary metabolites, but also due to the rhizospheric and endophytic microorganism roles (Podolich et al. 2015; Hanawi 2016). The latest Information related to the endophytic bacteria availability and roles in the Tagetes sp. is still limited.