Genomic insights of Pseudomonas nicosulfuronedens CST1-L11, a plant growth-promoting and stress-tolerating endophyte associated with native Musa spp. in Vietnam.

Endophytic bacteria contribute to sustainable agriculture by promoting plant growth and enhancing crop resilience to the challenges of climate change. Native bananas, well-adapted to harsh conditions, provide an ideal model for studying these bacteria. This study focused on investigating plant growth-promoting (PGP) traits of culturable endophytic bacteria from native banana plants on Ba Den Mountain, Vietnam. Among 26 isolates, strain CST1-L11 demonstrated significant PGP and stress-tolerating properties, including solubilizing 0.92 µg/mL inorganic phosphate, producing 2.27 µg/mL ammonia, synthesizing IAA without L-tryptophan (10.59 µg/mL) and with 0.1% L-tryptophan (38.48 µg/mL), and yielding 47.62% siderophore. At 1% NaCl, its growth (93.80%) was similar to the control, but sharply declined at 2-5% NaCl (3.03%) and ceased entirely beyond 6%. Strain CST1-L11 exhibited normal growth at pH = 5 and pH = 6, but growth dropped drastically at pH = 3 (0.74%), pH = 4 (4.72%). Besides, no growth was observed at 40 °C. Strain CST1-L11 was identified as Pseudomonas nicosulfuronedens based on an average nucleotide identity (ANI) of 98.96% with the RefSeq strain LAM1902 (GCA_005877905.1). Strain P. nicosulfuronedens CST1-L11 exhibits diverse genes linked to bioremediation, biomolecule transport and degradation, plant signal production, biofertilization, and indirect plant growth promotion, including colonization, stress control, and competitive exclusion. Key genes for nitrogen cycling, biofilm formation, motility (flagella, pili), and stress tolerance, alongside biosynthetic gene clusters (BGCs) for polyketides, peptides, siderophores, pigments, and antibiotics, were identified. CARD database comparisons revealed abundant multidrug efflux pump genes, predominantly from RND and MATE families, showcasing the strain's adaptability to diverse environments.