Characterization and potential of plant growth-promoting rhizobacteria on rice seedling growth and the effect on Xanthomonas oryzae pv. oryzae

Abstract

Abstract. Rahma H, Nurbailis, Kristina N. 2019. Characterization and potential of plant growth-promoting rhizobacteria on rice seedling growth and the effect on Xanthomonas oryzae pv. oryzae. Biodiversitas 20: 3654-3661. Xanthomonas oryzae pv. oryzae (Xoo), a major limiting factor in rice production, and the use of resistant Xoo varieties have failed to control the bacterial pathogens as well as increased yield. It is due to the diversity in pathotypes, caused by environmental factors, the nature of resistant variety used, and gene mutation. The aims of this study were to select rhizobacterial strains with the potential of suppressing Xoo growth and promoting the growth of rice seedlings. This experiment was conducted in a completely randomized design (CRD) using seven rhizobacterial isolates selected through a dual culture test, with four replications. There were four isolates that potential in inhibiting the growth of Xoo, namely KJKB5.4, LMTSA5.4, Bacillus cereus AJ34, and Alcaligenes faecalis AJ14, with inhibition diameters greater than 11.50 mm. Rhizobacterial supernatant of 4 potential isolates has a zone of inhibition ranging from 12.25 to 24.00 mm. Four potential isolates were also able to solubilize phosphate, produce indole acetic acid (IAA) growth hormone, and siderophore, as well as enhance the growth of rice seedlings. Based on the nucleic acid sequencing of LMTSA5.4, KJKB5.4, and RK12 isolates were identified as Stenotrophomonas malthopilia strain LMG 958 (99.13%) accession NR 119220.1, Stenotrophomonas pavanii strain LMG 25348 (95.84%) accession NR 118008.1 and Ochrobactrum ciceri strain ca-34 (92.91%) accession NR115819.1.

Plant Growth-Promoting Bacteria as an Emerging Tool to Manage Bacterial Rice Pathogens

“…Studies indicated that PGPB can act as bioinoculants as they promote plant growth, health, and yield [ 18 , 19 , 20 ]. Currently, PGPB also have been found acting against bacterial rice pathogens [ 21 , 22 , 23 ]. Hence, PGPB inoculation is emerging as an effective method to combat bacterial rice pathogens for enhancing rice production through eco-friendly approaches.…”

The potential of endophytic bacteria to suppress bacterial leaf blight in rice plants

“…The first inoculation of endophytic bacteria was carried out on seeds that have been surface sterilized. They were immersed in a suspension of endophytic bacteria for 15 minutes, then sown in a sprouting bath containing sterile planting media (Rahma et al 2019). As a control, rice seeds were soaked in sterile distilled water simultaneously.…”

Seed Bio-Priming to Enhance Seed Germination and Seed Vigor of Rice Using Rhizobacteria from The Northern Coast of Pemalang, Central Java, Indonesia

“…The application of rhizobacteria enhanced vegetative growth, which was triggered by the ability of rhizobacteria to produce auxins, especially indole acetic acid (IAA) (Chitra & Jijeesh, 2021;Chauhan et al, 2021). The ability of rhizobacteria to produce IAA will stimulate root elongation so that the root surface area that interacts with soil colloids increases and results in increased nutrient and water uptake (Purwanto et al, 2017;Purwanto et al, 2019;Rahma et al, 2019). Rahma et al, (2019) stated that the increase in root growth through the expansion of the root system was stimulated by hormones, thereby increasing nutrient uptake caused by the ability of rhizobacteria to dissolve nutrients such as P. Rhizobacteria can increase the availability of nutrients in the soil (N,P, K) so that nutrient uptake (N, P, K) increases, thereby increasing photosynthetic pigment and activity (Chauhan et al, 2021).…”

“…The ability of rhizobacteria to produce IAA will stimulate root elongation so that the root surface area that interacts with soil colloids increases and results in increased nutrient and water uptake (Purwanto et al, 2017;Purwanto et al, 2019;Rahma et al, 2019). Rahma et al, (2019) stated that the increase in root growth through the expansion of the root system was stimulated by hormones, thereby increasing nutrient uptake caused by the ability of rhizobacteria to dissolve nutrients such as P. Rhizobacteria can increase the availability of nutrients in the soil (N,P, K) so that nutrient uptake (N, P, K) increases, thereby increasing photosynthetic pigment and activity (Chauhan et al, 2021). Inoculation of rhizobacteria isolates can increase plant height and root length of rice seedlings through the ability to provide and mobilize the absorption of various nutrients in the soil through the ability to enhance capacity in synthesizing and modifying the concentra-tion of numerous phytohormones, dissolving P elements, and producing the Indole Acetic Acid hormone (Rahma et al, 2019).…”