Transcriptome analysis at mid-stage development seeds in litchi with contrasting seed size

Abstract

Litchi is a sub-tropical fruit crop with contrasting genotypes bearing fruits with variable seed size. Small seed size is a desirable trait in litchi, as it improves consumer preference and facilitates fruit processing. Seed specific transcriptome analysis was performed in two litchi genotypes with contrasting seed size to identify the genes associated with seed development in litchi fruits. The transcriptomic data from seeds at mid- development stages (16 to 28 days after anthesis) were de-novo assembled into 1,39,608 Trinity transcripts. Out of these, 6,325 transcripts expressed differentially between the two contrasting genotypes. Several putative genes for salicylic acid, jasmonic acid and brassinosteriod pathways were down-regulated in the small-seeded litchi. The putative regulators of seed maturation and seed storage were down-regulated in the small-seeded genotype. Embryogenesis, cell expansion, seed size and stress related Trinity transcripts exhibited differential expression. Further studies can lead to identification and characterization of early regulators of seed size in litchi.