ABSTRACT
Selection of plant growth-promoting endophytic bacteria isolated from Reutealis trisperma in various Indonesian agroecosystems

Nur Kholis Firdaus, Widi Amaria1*, Kurnia Dewi Sasmita1, Edi Wardiana1, Dibyo Pranowo1, Maman Herman1, Muhammad Syakir1, Miftakhurohmah Miftakhurohmah1, Asif Aunillah2, Gusmaini Gusmaini1, Muhammad Firdaus Oktafiyanto3, Ankardiansyah Pandu Pradana4, and Wahyu Wibawa1
 
Endophytic microbes play a crucial role in plant growth and health. Specifically, endophytic bacteria can be isolated from Reutealis trisperma (Blanco) Airy Shaw, a non-edible oil-producing plant prevalent across various Indonesian agroecosystems. This study aimed to select potential endophytic bacteria from R. trisperma in various Indonesian agroecosystems as plant-growth-promoting (PGP) through in vitro assays. Plant tissues were collected, and endophytic bacteria were isolated from five different R. trisperma planting areas. The bacterial colonies underwent biosafety testing; the surviving isolates were then evaluated in vitro for their ability to promote rice seedling growth, along with phytohormone analysis. The potential bacterial isolates were sequenced using 16S rRNA sequencing. The results indicated that 234 isolates passed the biosafety tests; 11 isolates were selected such as Serratia marcescens (BTB3, BNB2, KTA1, KTA5), Serratia sp. (NNB30), Klebsiella sp. (NKB2, SNA11, NTB22, GKB20), Citrobacter sp. (GKB21), and Lysinibacillus sp. (NNB25). However, isolates NTB22, NKB2, NNB30, and GKB20 have the highest potential as PGP.
Key words: Bacterial isolates, biosafety test, phytohormone, Reutealis trisperma.
1National Research and Innovation Agency (BRIN), Research Center for Estate Crops, Bogor, Indonesia.
2National Research and Innovation Agency (BRIN), Research Center for Agroindustry, Tangerang, Indonesia.
3Ministry of Agriculture, Agricultural Instrument Standardization Institute for Industrial and Beverage Crop, Sukabumi, Indonesia.
4University of Jember, Faculty of Agriculture, Plant Protection Program, Jember, Indonesia.
*Corresponding author (widi011@brin.go.id)