Effects of Temperature on Transcriptome Profiles in Cardiocrinum cathayanum Leaves

Abstract

Cardiocrinum cathayanum (Endl.) Lindl. (Liliaceae) is a promising species for ornamental and pharmaceutical usage. However, genomic responses of C. cathayanum to temperature have not been investigated. In the present study, C. cathayanum leaves were cultivated at 10, 20, and 30°C, and leaves were collected for transcriptome sequencing. Overall, 36.9 to 44.1 M clean reads were obtained, which finally assembled 48 120 unigenes. Among these unigenes, 49.39% could be annotated to at least one public database. Compared with 20°C treatment, 381 and 303 unigenes were significantly upregulated, 580 and 1399 were significantly downregulated in 10 and 30°C treatments, respectively. Real-time qPCR analyses on selected 12 unigenes showed similar tendencies to those calculated on transcriptome sequencing. Compared with 20°C treatment, exposure to 10°C significantly affected the pentose and glucuronate interconversions, starch and sucrose metabolism pathways. Further exploration suggested that D-galacturonate and trehalose were accumulated at 10°C, which would enhance the tolerance to cold stress. Besides, 10°C treatment inhibited the biosynthesis of unsaturated fatty acids and α-linolenic acid metabolism. These changes might negatively affect C. cathayanum growth. At 30°C, 40 of 42 differentially expressed genes (DEGs) in the starch and sucrose metabolism, all the 27 DEGs in the glycolysis/gluconeogenesis and all the 17 DEGs in the fructose and mannose metabolism were significantly downregulated, in comparison to 20°C treatment. These changes demonstrated that high temperature greatly inhibited carbohydrate metabolism in C. cathayanum leaves. Overall, the present study contributed new insights to understand the genomic responses of C. cathayanum leaves to various temperatures.