Eucalyptus growth promotion by endophytic Bacillus spp

Area of Science:

• Microbiology
• Plant Science
• Forestry

Background:

• Clonal eucalyptus propagation faces challenges due to poor root and shoot development in some high-yield clones.
• Endophytic microorganisms reside within plants and can promote growth without causing harm.
• Identifying beneficial endophytes offers a sustainable approach to enhance eucalyptus cultivation.

Purpose of the Study:

• To isolate and identify endophytic bacteria from Eucalyptus.
• To evaluate the plant growth-promoting potential of these isolates on E. urograndis clone 4622.
• To assess the indole acetic acid production, nitrogen fixation, and phosphate solubilization capabilities of the isolates.

Main Methods:

• Isolation of endophytic bacteria from healthy eucalyptus plants.
• Greenhouse testing of 18 bacterial isolates for plant growth promotion on E. urograndis.
• Biochemical assays for indole acetic acid production, nitrogen fixation, and phosphate solubilization.
• Identification of isolates using partial 16S rRNA gene sequencing.

Main Results:

• Bacillus subtilis was the most frequently identified species among the isolates.
• Several Bacillus species, including B. licheniformis and B. subtilis, were identified as novel eucalyptus endophytes.
• Bacillus sp strain EUCB 10 demonstrated a significant increase in both root and aerial part growth of eucalyptus plantlets under greenhouse conditions across different seasons.

Conclusions:

• Endophytic bacteria, particularly Bacillus species, hold significant potential for promoting the growth of E. urograndis.
• Bacillus sp strain EUCB 10 is a promising candidate for improving vegetative propagation and overall growth in clonal eucalyptus.
• This study highlights the importance of exploring endophytic microbial communities for sustainable agricultural and forestry practices.