Transcriptome survey and expression analysis reveals effects and metabolic pathways of Yuluxiang Pear in response to drought stress

Background: Pear is one of the most important economic fruits worldwide. The quality and productivity is frequently threatened by drought disaster, but the effects mechanism of drought stress on pear has not been well understood, especially in respond to drought stress at the gene transcription levels. Results: : That showed that drought stress weakened antioxidant systematization and the synthesis of photosynthetic pigment of Yuluxiang Pear leaves, and the reduced light utilization and photosynthetic productivity finally resulted in the inhibited fruit development. The transcriptome from leaves were sequenced and analyzed using Illumina HiSeq 2500 to evaluate the effects of drought stress on the expression of genes in different biosynthetic pathways. Deferentially expressed genes analysis showed that the enzyme genes involved in lignin biosynthesis were up-regulated by drought stress, and the promoted lignification process may be beneficial to decrease the transpiration rate and increase water use efficiency of Yuluxiang Pear leaves. The up-regulated malate dehydrogenase and adenosylmethionine decarboxylase were also observed in drought stress groups, and the activated soluble sugar biosynthesis could be helpful to promote osmotic regulation and increase antioxidant capacity to enhance drought resistance of leaves. Drought stress increased the expression of enzyme genes related with hormones biosynthesis including ethylene, abscisic acid, and gibberellin, suggesting promoted cell proliferation and slowed young leaves growth. Conclusions: : Present study reveals that drought stress severely decrease photosynthetic productivity to negatively affect fruit development, and the inhibited photosynthesis could be closely related with drought-induced lignification and hormones promoting leaf abscission.