Eksplorasi Bakteri Endofit Asal Tanaman Lamtoro (Leucaena leucocephala L.) sebagai Agens Biokontrol Nematoda Puru Akar (Meloidogyne spp.) pada Tanaman Okra (Abelmoschus esculentus L. Moench)

Abstract

Nematoda puru akar Meloidogyne spp. merupakan nematoda parasit penting pada okra yang menyebabkan kehilangan hasil dan kerugian secara ekonomi. Gejala yang disebabkan oleh Meloidogyne spp. yaitu tanaman kerdil, layu, daun menguning, dan akar berpuru. Meloidogyne spp. dapat berinteraksi dengan patogen lain seperti Fusarium oxysporum. Tujuan dari penelitian ini adalah mendapatkan bakteri endofit asal tanaman lamtoro yang berpotensi sebagai agen biokontrol terhadap Meloidogyne spp. dan mengetahui pengaruhnya terhadap pertumbuhan tanaman okra (Abelmoschus esculentus). Bakteri endofit diisolasi dari akar dan batang tanaman lamtoro menggunakan metode sterilisasi permukaan dengan NaOCl 1% dan alkohol 70%, kemudian dikulturkan pada media tryptose soy agar (TSA). Isolat bakteri endofit diseleksi keamanan hayatinya menggunakan uji agar darah dan uji hipersensitif. Isolat bakteri endofit terpilih dilakukan uji in vitro terhadap juvenil 2 Meloidogyne spp., cendawan Fusarium oxysporum dan diuji keefektifannya dalam penekanan puru akar pada tanaman okra di rumah kaca. Hasil penelitian diperoleh sebanyak 411 isolat bakteri endofit berhasil diisolasi dari akar dan batang tanaman lamtoro. Hasil uji keamanan hayati sebanyak 5 isolat bakteri endofit tidak berpotensi patogen terhadap mamalia maupun tumbuhan. Hasil pengujian secara in vitro terhadap juvenil 2 Meloidogyne spp. menunjukan bahwa 5 isolat bakteri endofit tersebut mampu menyebabkan mortalitas pada juvenil 2 Meloidogyne spp. berkisar antara 81.67%-98.67% dan menghambat pertumbuhan F. oxysporum berkisar antara 27.33%-45%. Perlakuan bakteri endofit mampu meningkatkan bobot tajuk tanaman okra, menekan keparahan penyakit berkisar antara 69.23%-76.92% dan menekan populasi nematoda berkisar antara 60%-71.41% pada percobaan di rumah kaca. Hasil identifikasi molekuler ke 5 isolat bakteri endofit tersebut meliputi Providencia vermicola (AD7), Providencia rettgeri (AD16 dan BGB21), Proteus vulgaris (AGB40) dan Alcaligenes faecalis (AS8)

Nematodes (Meloidogyne spp.) on Okra (Abelmoschus esculentus L. Moench. Supervised by ABDUL MUNIF Root-knot nematodes (Meloidogyne spp.) is a plant parasitic nematode on Okra that causes of yield and economic losses. Symptoms caused by Meloidogyne spp. namely dwarf plants, withered, yellowed leaves, and rooted roots. Meloidogyne spp. can interact with pathogens such as Fusarium oxysporum. The objective at this research was to obtain endophytic bacteria from lamtoro plants as biocontrol agents that have the potential to control Meloidogyne spp. and to study the effects on the growth of okra plants (Abelmoschus esculentus). Endophytic bacteria were isolated from the roots and stems of the lamtoro plant using the surface sterilization method with 1% NaOCl and 70% alcohol, then cultured on tryptic soy agar (TSA) media. Endophytic bacterial isolates were selected for their biological safety using blood agar tests and hypersensitivity tests. Selected endophytic bacterial isolates were tested in vitro against juvenile 2 Meloidogyne spp., Fusarium oxysporum fungi and tested for their effectiveness in suppressing the root gall in okra plants in greenhouses. The results showed 411 endophytic bacterial isolates were successfully isolated from the roots and stems of the lamtoro plants. After biological safety test, 5 endophytic bacterial isolates were not potentially pathogenic to mammals or plants. Under in vitro showed 5 endophytic bacterial isolates were able to cause the percent mortality of juvenile 2 Meloidogyne spp. from 81.67%-98.67% and could inhibit the growth of F. oxysporum from 27.33%-45%. The treatment of endophytic bacteria was able to increase the fresh weight of okra plants, adn suppress the severity of the disease ranging from 69.23%-76.92% and nematode population ranging from 60%-71.41% in greenhouse experiments. The results of molecular identification of the 5 endophytic bacterial isolates namely Providencia vermicola (AD7), Providencia rettgeri (AD16 and BGB21), Proteus vulgaris (AGB40) and Alcaligenes faecalis (AS8)