Rhizosphere microbiome influences fruit quality in citrus

Area of Science:

• Plant Science
• Microbiology
• Agricultural Science

Background:

• Fruit quality is influenced by genetics and environment, with soil microbes playing a role in nutrient uptake.
• The direct impact of the rhizosphere microbiome on fruit quality, particularly sugar concentration, is not well understood.

Purpose of the Study:

• To investigate the influence of the rhizosphere microbiome on fruit quality in Satsuma mandarin and Navel orange.
• To identify specific microbial mechanisms and nutrient interactions related to fruit sugar content.

Main Methods:

• Correlation analysis between rhizosphere core microbiota, soil nutrients, and fruit quality indices.
• Bacterial strain and consortium inoculation experiments.
• Metagenomic analysis to identify microbial functions.
• Iron (Fe) content analysis in citrus leaves.
• Field application of chelated-Fe fertilizer.

Main Results:

• Rhizosphere microbiota and soil nutrients positively correlated with fruit quality.
• Bacterial operational taxonomic units (OTUs) explained significant variation in fruit quality.
• Inoculation with specific bacterial strains and consortia increased fruit sugar concentrations.
• Microbes associated with sugar content were linked to iron utilization via siderophore biosynthesis.
• Bacterial strains enhanced leaf iron content, and chelated-Fe fertilizer increased fruit sugar.

Conclusions:

• The rhizosphere microbiome influences citrus fruit sugar concentration through optimized iron acquisition.
• Microbial iron uptake mechanisms contribute to sugar accumulation and improved fruit quality.
• Targeting soil microbes and iron availability presents a strategy for enhancing citrus fruit quality.