Secondary Metabolite Activities of Endophytic Bacteria from White Turmeric (Curcuma zedoaria Rosc.) as Plant Growth Promoter

Abstract

Bakteri endofit mengkolonisasi jaringan tanaman dan berkontribusi terhadap pertumbuhan, perkembangan dan adaptasi tanaman inang. Penelitian bertujuan untuk mengkaji keragaman bakteri endofit dari tanaman kunyit putih (Curcuma zedoaria) dan mengetahui aktivitasnya sebagai pemacu pertumbuhan tanaman. Tanaman kunyit putih diperoleh dari Balai Penelitian Tanaman Rempah dan Obat (Balittro). Isolasi bakteri endofit dari bagian daun, rimpang primer dan sekunder kunyit putih menggunakan media Nutrient Agar (NA). Identifikasi dilakukan berdasarkan 16S rDNA. Isolat tersebut selanjutnya diuji kemampuannya sebagai pemacu pertumbuhan tanaman dan penghasil enzim. Berdasarkan karakteristik morfologi, diperoleh 21 isolat, terbanyak diperoleh dari bagian rimpang primer (47,62%), rimpang sekunder (19,05%) dan daun (33,33%). Hasil sekuensing 16S rDNA menunjukkan komunitas bakteri endofit pada tanaman kunyit putih terdiri dari empat filum yaitu β-proteobacteria, γ-proteobacteria, Flavobacteria dan Firmicutes yang merepresentasikan delapan genus. Lima isolat mempunyai aktivitas sebagai pemacu pertumbuhan tanaman, sedang enam isolat menghasilkan enzim.  Terdapat 13 isolat mempunyai aktivitas ganda sebagai pemacu pertumbuhan tanaman dan aktivitas enzimatik, sedangkan delapan isolat hanya memiliki salah satu aktivitas tersebut.  Bakteri endofit yang berpotensi sebagai pemacu pertumbuhan tanaman berpotensi digunakan sebagai pupuk hayati untuk menunjang pertumbuhan tanaman kunyit putih.Endophytic bacteria colonize the plant tissue and contribute to the host plant's growth, development, and adaptation. This study aimed to examine the endophytic bacteria diversity associated with white turmeric (Curcuma zedoaria) and determine its activity as a plant growth promoter. White turmeric plants were obtained from the Indonesian Spices and Medicinal Crop Research Institute (Balittro). The isolation of endophytic bacteria from leaves, a primary and secondary rhizome of white turmeric using Nutrient Agar (NA) medium. Identification of the isolates was conducted based on 16S rDNA. The isolates were tested for their ability as a plant growth promoter and enzyme producer. Based on the morphological characteristic, 21 isolates were obtained from the primary rhizome (47.62%), secondary rhizome (19.05%), and leaves (33.33%), respectively. The sequencing result of 16S rDNA showed that the endophytic bacteria community consisted of four phyla, β-proteobacteria, γ-proteobacteria, Flavobacteria, Firmicutes, which represented eight genera. Five isolates had several activities as a plant growth promoter, while six isolates had several enzymatic activities. Thirteen isolates had both activities, as a plant growth promoter and enzyme producer, while eight isolates only had single action. Endophytic bacteria potential as plant growth promoters can be used for supporting the cultivation of white turmeric plants