Transcriptome and Metabolome Profiling Reveal the Resistance Mechanisms of Rice against Brown Planthopper

Area of Science:

• Plant Science
• Agricultural Entomology
• Molecular Biology

Background:

• The brown planthopper (BPH) is a major pest of rice, causing significant yield losses globally.
• Understanding rice's defense mechanisms against BPH is crucial for developing sustainable pest management strategies.
• Previous research has identified some plant defense responses, but a comprehensive understanding of transcriptomic and metabolic changes is lacking.

Purpose of the Study:

• To elucidate the physiological and molecular mechanisms underlying rice resistance to BPH.
• To compare transcriptomic and metabolic profiles between BPH-susceptible and -resistant rice varieties.
• To identify key genes, metabolites, and pathways involved in rice-BPH interactions.

Main Methods:

• Comparative transcriptomic and metabolomic analyses of leaf sheaths from susceptible and resistant rice varieties under BPH infestation.
• Identification of differentially expressed genes (DEGs) and differentially accumulated metabolites (DAMs).
• Correlation analysis between DEGs and DAMs, pathway enrichment analysis, and functional validation through exogenous hormone application and dietary supplementation.

Main Results:

• Resistant rice varieties exhibited reduced BPH settling, feeding, and growth compared to susceptible varieties.
• BPH infestation induced more significant metabolic changes in susceptible rice, with flavonoids downregulated in susceptible and upregulated in resistant rice.
• Transcriptomic analysis revealed more DEGs in susceptible rice, with stimulus-related genes upregulated in resistant rice. Key pathways identified include phenylpropane biosynthesis, flavonoid biosynthesis, and plant hormone signal transduction.
• Correlation analysis confirmed strong links between DEGs and DAMs. Indole-3-acetic acid (IAA) levels were lower, and salicylic acid (SA) levels were higher in resistant rice. Exogenous IAA reduced resistance, while SA increased it. Lignin content was constitutively higher in resistant rice.
• Epigallocatechin supplementation in artificial diets impaired BPH performance.

Conclusions:

• Rice enhances resistance to BPH by upregulating epigallocatechin and downregulating indole-3-acetic acid (IAA).
• The study provides novel insights into the molecular and metabolic basis of rice resistance to BPH, integrating transcriptomic and metabolomic data.
• Findings offer valuable information for developing BPH-resistant rice cultivars and integrated pest management strategies.