Integrating transcriptome and metabolome analyses of the response to cold stress in pumpkin (Cucurbita maxima).

Fengmei Li,Xiuping Lu,Pengfei Duan,Yanjiao Liang,Jian Cui,Sara Amancio

doi:10.1371/journal.pone.0249108

Abstract

Cucurbita maxima belong to the genus Cucurbita and are of nutritional and economic importance. Physiological activity, transcriptome, and metabolome analyses of leaf samples from the C. maxima inbreding line IL7 treated at 5 °C and 25 °C were performed. Cold stress resulted in a significant increase in the malondialdehyde content, relative electrical conductivity, soluble protein, sugar content, and catalase activity. A total of 5,553 differentially expressed genes were identified, of which 2,871 were up-regulated and 2,682 down-regulated. In addition, the transcription of differentially expressed genes in the plant hormone signal transduction pathway and transcription factor families of AP2/ERF, bHLH, WRKY, MYB, and HSF was activated. Moreover, 114 differentially expressed metabolites were identified by gas chromatography time-of-flight mass spectrometry, particularly through the analysis of carboxylic acids and derivatives, and organooxygen compounds. The demonstration of a series of potential metabolites and corresponding genes highlighted a comprehensive regulatory mechanism. These findings will provide novel insights into the molecular mechanisms associated with the response to cold stress in C. maxima.

Highlights

Low temperature is one of the major environmental factors limiting agricultural productivity and the geographic distribution of many plant species [1]
The relative electric conductivity (REC), soluble sugar (SS) content, soluble protein content, POD, and CAT activity in cold-treated IL7 showed a significant increase at 24 h compared with the control, and there was a significant decrease in the Soil Plant Analysis Development (SPAD) index of cold-treated IL7 relative to the control (Fig 1A–1D, 1F and 1G)
The SS content in the leaves of C. maxima increased 1.88-fold in fighting the cold stress. These results strongly suggested that the cold-stressed IL7 seedlings actively mounted a stress response after they were exposed to 5 ̊C

Summary

Introduction

Low temperature is one of the major environmental factors limiting agricultural productivity and the geographic distribution of many plant species [1]. Some plant species have developed a remarkable ability to adapt to low temperatures [2]. After plant exposure to cold stress, a series of physiological and biochemical changes at the molecular and cellular levels are induced to adapt and survive under cold environments [4,5]. These changes include increased accumulation of antioxidant enzymes and non-enzymatic molecules which may neutralize or counteract the harmful effects of reactive oxygen specie (ROS) and protect the plants from cold stress [6].

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Results

Discussion

Conclusion