Decoding xenia effects on 'Jinsha' pomelo: Insights from physiological, transcriptomics and metabolomics analyses

Area of Science:

• Plant reproductive biology
• Fruit science
• Metabolomics and transcriptomics

Background:

• Xenia describes immediate pollen effects on seed and fruit development.
• Pomelo fruit quality is influenced by pollen source, impacting seed traits and primary metabolites.

Purpose of the Study:

• To investigate the xenia effect on 'Jinsha' pomelo using Grapefruit and 'Majia' pomelo pollen.
• To elucidate the molecular and metabolic mechanisms underlying xenia-induced changes in pomelo seed and fruit characteristics.

Main Methods:

• Pollination experiments with different pollen sources ('Jinsha' pomelo with Grapefruit and 'Majia' pomelo pollen).
• Analysis of seed number, primary metabolites (soluble sugar, amino acid), pollen tube penetration, and cytokinin content.
• Integrated metabolomics and transcriptomics analysis to identify key metabolic pathways and genes.

Main Results:

• Pollination with different pollen sources caused significant variations in seed number and primary metabolite content.
• Differences in pollen tube entry and cytokinin levels at 5 days post-pollination correlated with seed trait discrepancies.
• Gene expression analysis revealed altered sucrose, starch, glycolysis, and amino acid metabolism pathways, impacting fructose, glucose, and amino acid levels.

Conclusions:

• Xenia significantly affects pomelo seed and fruit quality through altered embryo sac development and metabolic reprogramming.
• Specific genes, including novel.155 (HK), Cg2g040280 (bglX), Cg4g020710 (ISA), and Cg3g021210 (P4HA), were identified as crucial hubs in xenia response.
• This study provides insights into the genetic and metabolic basis of xenia in pomelo, offering targets for breeding improved fruit varieties.