Potential Application of Rhizobacteria Isolated from the Central Highland of Vietnam as an Effective Biocontrol Agent of Robusta Coffee Nematodes and as a Bio-Fertilizer

Abstract

Robusta coffee is a major commercial crop in the Central Highland of Vietnam with high economic and export value. However, this crop is adversely affected by various pathogens, particularly nematodes. This study aimed to screen active anti-nematode rhizobacterial strains for sustainable coffee production. Among more than 200 isolates, the isolate TUN03 demonstrated efficient biocontrol with nearly 100% mortality of J2 coffee nematodes Meloidogyne spp. and 84% inhibition of nematode egg hatching. This active strain was identified as Pseudomonas aeruginosa TUN03 based on its 16S rRNA gene sequence and phylogenetic analysis. In greenhouse tests, the strain TUN03 significantly reduced the coffee nematode population in the rhizome-soil with an 83.23% inhibition rate and showed plant growth-promoting effects. Notably, this is the first report of the nematicidal effect of P. aeruginosa against coffee nematodes. This potent strain further showed an antifungal effect against various crop-pathogenic fungi and was found to be the most effective against Fusarium solani F04 (isolated from coffee roots) with a 70.51% inhibition rate. In addition, high-performance liquid chromatography analysis revealed that this bacterial strain also secretes plant growth regulators including indole acetic acid (IAA), gibberellic acid (GA3), kinetin, and zeatin in significant amounts of 100, 2700, 37, and 9.5 µg/mL, respectively. The data from this study suggest that P. aeruginosa TUN03 may be a potential biocontrol agent and biofertilizer for the sustainable production of Robusta coffee and other crops.

Novel α-Amylase Inhibitor Hemi-Pyocyanin Produced by Microbial Conversion of Chitinous Discards

“…The use of Pseudomonas aeruginosa has been reported in agriculture [ 32 , 33 , 34 , 35 ], environment management [ 36 , 37 ], and for the production of secondary metabolites such as rhamnolipid, vanillin, enzymes, pigments, and plant promoting compounds with a wide range of applications [ 38 , 39 , 40 , 41 , 42 , 43 ]. Based on our recent review of published studies, there is no report on the use of this genus for the production of aAIs via fermentation.…”

“…Bacterial strains were obtained from our previous works [ 43 , 67 ]. Discarded marine chitinous materials such as shrimp shells, shrimp heads, crab shells, and squid pens were obtained from Shin-Ma Frozen Food Co. (I-Lan, Taiwan).…”

Novel α-Amylase Inhibitor Hemi-pyocyanin Produced by Microbial Conversion of Chitinous Discards

“…The bacterial strains were obtained from our previous works [41,63]. The marine chitinous discards such as shrimp shells, shrimp heads, crab shells, and squid pens were required from Shin-Ma Frozen Food Co. (I-Lan, Taiwan).…”

“…The α-amylase inhibitory activity of tested bacterial strains. Pseudomonas aeruginosa has been reported as valuable for its utilization in agriculture [30][31][32][33], environment management [34][35], and in the industry for the production of some secondary metabolites such as rhamnolipid, vanillin, enzymes, pigments, and plant promoting compounds having their wide range of applications [36][37][38][39][40][41]. Based on our recent review of published studies, there is no report on using this genus for the production of aAIs via fermentation.…”

Taxonomic and functional profiles of Coffea canephora endophytic microbiome in the Central Highlands region, Vietnam, revealed by analysis of 16S rRNA metagenomics sequence data

“…Among regions in Vietnam, the Central Highlands is the capital of the coffee plantation and production [2] . Previous works have established a dataset of rhizospheric microbial diversity and its functionality to develop sustainable Robusta coffee production techniques in this region [3] , [4] , [5] , [6] ; however, a dataset of the endophytic microbiome of this plant species has been found is still unknown. The work presented here is the first report on the microbial and functional diversity of the endophytic microbiome of Coffea canephora L. grown in the region.…”