Abstract
Low temperature induces changes in plants at physiological and molecular levels, thus affecting growth and development. The Lanzhou lily (Lilium davidii, var. unicolor) is an important medicinal plant with high economic value. However, the molecular mechanisms underlying its photosynthetic and antioxidation responses to low temperature still remain poorly understood. This study subjected the Lanzhou lily to the two temperatures of 20°C (control) and 4°C (low temperature) for 24 h. Physiological parameters related to membrane integrity, photosynthesis, antioxidant system, and differentially expressed genes were investigated. Compared with control, low temperature increased the relative electrical conductivity by 43.2%, while it decreased net photosynthesis rate, ratio of variable to maximal fluorescence, and catalase activity by 47.3%, 10.1%, and 11.1%, respectively. In addition, low temperature significantly increased the content of soluble protein, soluble sugar, and proline, as well as the activity of superoxide dismutase and peroxidase. Comparative transcriptome profiling showed that a total of 238,109 differentially expressed genes were detected. Among these, 3,566 were significantly upregulated while 2,982 were significantly downregulated in response to low temperature. Gene Ontology enrichment analysis indicated that in response to low temperature, the mostly significantly enriched differentially expressed genes were mainly involved in phosphorylation, membrane and protein kinase activity, as well as photosynthesis, light harvesting, light reaction, and alpha,alpha-trehalose-phosphate synthase activity. Kyoto Encyclopedia of Genes and Genomes enrichment analysis also indicated that the most significantly enriched pathways involved ribosome biogenesis in eukaryotes, phenylalanine metabolism, circadian rhythm, porphyrin and chlorophyll metabolism, photosynthesis of antenna proteins, photosynthesis, and carbon fixation in photosynthetic organisms. Moreover, the expression patterns of 10 randomly selected differentially expressed genes confirmed the RNA-Seq results. These results expand the understanding of the physiological and molecular mechanisms underlying the response of the Lanzhou lily to low temperature stress.
Highlights
Under natural conditions, plants often suffer from a variety of biotic and abiotic stresses, such as drought [1,2,3,4], salt stress [5], high temperature [6], and chilling injury [7,8]
LT significantly affected indicators related to photosynthesis, osmotic regulation, and antioxidant system in leaves of the Lanzhou lily (Fig 1)
LT significantly decreased cell membrane stability, photosynthesis rate (Pn), and Fv/Fm, while it increased the contents of osmotic conditional substances and the activities of antioxidant enzymes (SOD and POD) in the Lanzhou Lily, resisting LT stress
Summary
Plants often suffer from a variety of biotic and abiotic stresses, such as drought [1,2,3,4], salt stress [5], high temperature [6], and chilling injury [7,8]. Low temperature is one of the most common abiotic stresses and severely affects plant growth, development, production, and quality [12,13,14,15], especially during late autumn, winter, and early spring in northwest China. Several studies reported that LT significantly reduced net photosynthesis rate (Pn) and the ratio of variable to maximal fluorescence (Fv/Fm) [24,25,26,27] in plants; it increased the activity of antioxidant enzymes such as superoxide dismutase (SOD, EC 1.15.1.1) and catalase (CAT, EC 1.11.1.6) [28] to resist possible injury. Investigating the physiological and molecular mechanisms underlying the cold tolerance may provide information for both the environmental regulation and the genetic improvement of plant growth and production
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
