Figures (2)  Tables (3)

    • Figure 1. 

      Representatives of rhizobacteria (a) capable of phosphate solubilization as indicated by the clear zone around the colony (arrow) and (b) not capable of phosphate solubilization grown on Pikovskaya's agar medium for 5 d at 30 °C.

    • Figure 2. 

      Neighbor joining tree of rhizobacteria isolates and their closely related species generated using BLAST. Bootstrap values are based on 1000 replications analyzed using MEGAX.

    • Rhizosphere sourceIsolateColony shapeColony elevationColony marginColony colorGram reactionCell shape
      LibericaPCL 1.2IrregularRaisedEntireWhiteNegativeRods
      LibericaPCL 2.1CircularFlatSerrateWhitePositiveRods
      LibericaPCL 2.3IrregularConvexEntireWhiteNegativeRods
      RobustaPCR 1.1CircularRaisedEntireYellowNegativeRods
      RobustaPCR 1.3IrregularCrateriformUndulateCreamPositiveRods
      RobustaPCR 1.5CircularFlatCurledWhiteNegativeRods

      Table 1. 

      Morphological characteristics of rhizobacteria from the coffee rhizosphere.

    • IsolatePhosphate
      solubilization
      index (mm)      		Biocontrol activityAbiotic stress tolerance
      HCN productionAmylaseProtease PectinaseNaCl (%)pHMnSO4 (ppm)CuSO4 (ppm)Pb(C2H3O2)2 (ppm)
      PCL 1.23.1 ± 0.5−−−−74 – 111,600400800
      PCL 2.13.5 ± 0.5−+−−74 – 111,600400800
      PCL 2.33.1 ± 0.5−−−−34 – 111,600400800
      PCR 1.13.5 ± 0.5−−+−34 – 111,600800800
      PCR 1.32.5 ± 0.5+++−54 – 11800400800
      PCR 1.52.8 ± 0.5−+++34 – 111,600400800
      HCN, hydrogen cyanide; NaCl, sodium chloride; MnSO4, manganese sulphate; CuSO4, copper sulphate; Pb(C2H3O2)2, lead acetate.

      Table 2. 

      Six rhizobacterial isolates showing phosphate solubilization, biocontrol activities, and abiotic stress tolerance.

    • IsolateIdentityClosest neighbor (type strain)Similarity (%)Accession no.
      PCL 1.2Pantoea rwandensisPantoea rwandensis strain LMG 2627597.44NR_118121.1
      PCL 2.1Bacillus pseudomycoidesBacillus pseudomycoides97.23NR_114422.1
      PCL 2.3Pantoea sp.Pantoea agglomerans strain JCM123693.62NR_111998.1
      PCR 1.1Burkholderia cepaciaBurkholderia cepacia ATCC 25416 strain LMG 122297.17NR_114491.1
      PCR 1.3Bacillus sanguinisBacillus sanguinis strain BML-BC00499.51NR_175555.1
      PCR 1.5Burkholderia sp.Burkholderia pseudomallei strain ATCC 2334386.66NR_043553.1

      Table 3. 

      Molecular identity of rhizobacteria isolates from coffee rhizosphere.