Transcriptome Changes Associated with Boron Applications in Fruits of Watercore-susceptible Pear Cultivar

Watercore is a common physiological disorder in pear and is closely related to excessive accumulation of sorbitol and sucrose. Our previous research found the watercore incidence of ‘Akibae’ (Pyrus pyrifolia cv. Akibae) fruit significantly decreased after boron application (BA). Moreover, foliar spray of boric acid also significantly improved fruit quality. To uncover the mechanisms underlying pear fruit response to BA, a comprehensive transcriptome analysis was performed in this study. Transcriptome results revealed a total of 3146 up-regulated and 1145 down-regulated differently expressed genes (DEGs) between control and treated fruits of ‘Akibae’ pear, respectively. BA significantly induced expression of sorbitol metabolism and sucrose metabolism genes. Besides, BA also increased the expression of starch degradation, fatty acid synthesis, IAA (indole-3-acetic acid) degradation, GA (gibberellin acid) synthesis and inhibit the expression of ethylene synthesis genes. Overall, these findings suggested that BA alleviated ‘Akibae’ watercore occurrence and improve fruit quality by regulating the decrease of sorbitol and sucrose, increased of fatty acid and a balance of plant hormone. Our results provided further information for understanding the molecular mechanism of the effect of boron application on pear fruit.