De novo assembly of expressed transcripts and analysis of pistil to identify genes involved in early stage of pollination in Liriodendron chinense

Plant sexual reproduction is a complicated and a key biological process with profuse interactions between pollen and pistil. This process determines whether fertilization will be successful or not and thus affect the seed setting. To explore the reason why L. chinense has a low seed setting ratio, transcriptome analysis on pistils of L. chinense during pollination were conducted. After analyzing the sequencing data, 206,858 unigenes with an average length of 646 bp were generated using the assembled transcripts. Among total unigenes, 3844 genes which expression fold change during early stage of pollination was higher or lower than 10 were selected as significant differentially expressed genes. 54 differentially expressed genes involved in sexual reproduction processes including the regulation of pollen tube growth process and double fertilization process might be partially causing the low seed setting in L. chinense . These results indicated that the barrier between pollen tube and pistil might be the reason why L. chinense have low seed setting. This study might be helpful to understand why L. chinense has such a low seed setting ratio.