Effects of Sphingobium yanoikuyae SJTF8 on Rice (Oryza sativa) Seed Germination and Root Development

The interaction between plant roots and rhizobacterium communities plays a crucial role in sustainable agriculture. We aimed to assess the effects of Sphingobium yanoikuyae SJTF8 on rice seed germination and development, as well as to observe the effects of different concentrations of S. yanoikuyae SJTF8 on the root systems of rice seedlings. The bacteria are best known for their role in the bioremediation and biodegradation of pollutants, and thus far, there is research that supports their agricultural prospects. The experiment comprised five different S. yanoikuyae SJTF8 concentrations: SP-y 8 (10⁸ CFU/mL); SP-y 7 (10⁷ CFU/mL); SP-y 6 (10⁶ CFU/mL); SP-y 5 (10⁵ CFU/mL); SP-y 4 (10⁴ CFU/mL). We used sterilized water as the control treatment. The bacteria triggered the synthesis of IAA, while the seedling root lengths substantially increased on the 12th day after germination. The high application concentrations of S. yanoikuyae SJTF8 resulted in higher IAA production (with the SP-y 7 and SP-y 8 concentrations ranging from 151,029 pg/mL to 168,033 pg/mL). We found that the appropriate concentrations of S. yanoikuyae SJTF8 when applied as an inoculant were SP-y 7 and SP-y 6, based on the increased root growth and biomass production. The bacteria were also able to solubilize phosphorous. The growth response from the rice seedlings when inoculated with S. yanoikuyae SJTF8 presents the potential of the bacteria as a growth promotor. Its application in rice cultivation could be a sustainable approach to rice production.