Identification and evaluation of suitable reference genes for gene expression analysis in rubber tree leaf

Area of Science:

• Plant molecular biology
• Genomics
• Biotechnology

Background:

• Accurate gene expression profiling relies on normalization using stable reference genes.
• Previous studies identified reference genes for rubber tree laticifers, but leaf expression stability remains uncharacterized.

Purpose of the Study:

• To identify stable reference genes for rubber tree leaf across developmental stages and abiotic/biotic stresses.
• To validate novel candidate reference genes for accurate gene expression normalization.

Main Methods:

• Quantitative real-time PCR (qPCR) was used to evaluate the expression stability of 30 candidate genes.
• Candidate genes included ubiquitin-proteasome system components, previously identified genes, and specific genes.

Main Results:

• Eleven ubiquitin-proteasome system genes demonstrated excellent potential as reference genes.
• An ubiquitin conjugating enzyme (RG0099) and three ubiquitin-protein ligases (RG0928, RG2190, RG0118) showed high expression stability across all tested conditions.
• Novel candidate genes exhibited superior stability compared to previously identified ones.

Conclusions:

• Ubiquitin conjugating enzyme (RG0099) and ubiquitin-protein ligases (RG0928, RG2190, RG0118) are validated as suitable reference genes for rubber tree leaf.
• Using multiple reference genes is recommended for robust gene expression data normalization.
• Findings enhance the reliability of genomics studies in rubber trees and potentially other species.