Full-length transcriptome sequencing reveals a low-temperature-tolerance mechanism in Medicago falcata roots

Abstract

Background Low temperature is one of the main environmental factors that limits crop growth, development and production. Medicago falcata is an economically and ecologically important legume that is closely related to alfalfa and exhibits better tolerance to low temperature than alfalfa. Understanding the low-temperature-tolerance mechanism of M. falcata is important for the genetic improvement of alfalfa. Results In this study, we explored the transcriptomic changes in low-temperature-treated M. falcata roots by combining SMRT and NGS technologies. A total of 115,153 nonredundant sequences were obtained, and 8,849 AS events, 73,149 SSRs and 4,189 LncRNAs were predicted. A total of 111,587 genes from SMRT were annotated, and 11,369 DEGs were identified in this paper that are involved in plant hormone signal transduction, protein processing in endoplasmic reticulum, carbon metabolism, glycolysis/gluconeogenesis, starch and sucrose metabolism, and endocytosis pathways. We characterized 1,538 TF genes into 45 TF gene families, and the most abundant TF family was WRKY, followed by ERF, MYB, bHLH and NAC. A total of 134 genes were differentially coexpressed at all five temperature points, including 101 upregulated genes and 33 downregulated genes. PB40804, PB75011, PB110405 and PB108808 were found to play crucial roles in the tolerance of M. falcata to low temperature. The WGCNA results showed that the MEbrown module was significantly correlated with low-temperature stress in M. falcata. Electrolyte leakage was correlated with most genetic modules and corroborated that electrolyte leakage can be used as direct stress markers to reflect cell membrane damage from low-temperature stress in physiological assays. The consistency between the qRT-PCR results and RNA-Seq analyses confirm the validity of the RNA-Seq data and the analysis of the regulation of low-temperature stress in the transcriptome. Conclusions The full-length transcripts generated in this study provided a full characterization of the gene transcription of M. falcata and are useful for mining new low-temperature stress-related genes specific to M. falcata. These new findings facilitate the understanding of low-temperature-tolerance mechanisms in M. falcata.

Light Intensity: the Role Player in Cucumber Response to Cold Stress

“…In present study, we investigated the effect of light intensity and low temperature stress by detecting EL that re ects damage to cell membrane. EL has been introduced as a direct stress marker for indication of cell membrane damage from low-temperature stress (Cui et al 2019). In this study, the EL increased following the exposure of plants to low temperature and the increase in PPFD led to the higher EL level compared with that of plants exposed to control and darkness while in absence of light only negligible differences observed in EL of plants compared to control.…”

Cold stress tolerance of the intertidal red alga Neoporphyra haitanensis

“…Cold stress includes chilling (below 15 °C) and freezing (below 0 °C) [ 11 , 12 ]. In plants, moderate cold stress leads to chlorosis, progressive membrane and oxidative damage.…”