NIK FATIN QHARANIE Nik Mohd Kamaruzaman^1,a and AINIHAYATI Abdul Rahim^1,2,3,b,*

¹Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, Jeli, Kelantan, Malaysia

²Microbial Technology Research Group, Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, 17600 Jeli, Kelantan, Malaysia

³Bioproduct and Bioprocessing Technology Research Group, Faculty of Bioengineering and Technology, Universiti Malaysia Kelantan, 17600 Jeli, Kelantan, Malaysia

^afatinqharanie@yahoo.com, ^bainihayati@umk.edu.my

Abstract. Methylotrophic bacteria known for its ability to thrive in diverse environments, including the rhizosphere of various plants. This bacterium is notable for its production of phytohormones, particularly Indole-3-Acetic Acid (IAA), which plays a crucial role in plant growth promotion. This project aimed to isolate methylotrophic bacteria from paddy rhizosphere on selective media namely ammonium mineral salt medium supplemented with 0.5 % methanol. An isolate labelled as UMK-PM5 was identified as Gram-negative bacteria with rod shape by gram staining. It was discovered that UMK-PM5 could produce 27.525 µg/mL of IAA which important in root and shoot development with the addition of L-Tryptophan (Trp) as an IAA precursor compared to control (1.674 µg/mL). In addition, the strain also able to grow on Burk’s medium which is nitrogen free medium indicates its ability to fix nitrogen which an important mechanism to produce ammonium or nitrate that available for plant uptake. Furthermore, the MR297 paddy seeds treated with this isolate was shown to have a faster germination rate compared to control, and develop a better shoot, and root elongation, hence improve the seedling vigour of paddy seeds with 555.800 ± 64.401. These findings suggest that UMK-PM5 holds promise as a plant growth promoter for sustainable agriculture, particularly in rice cultivation.

Keywords: Methylotrophic bacteria, indole-3-acetic acid production, nitrogen fixing.