Associating transcriptional regulation for rapid germination of rapeseed (Brassica napus L.) under low temperature stress through weighted gene co-expression network analysis

Abstract Background RNA Sequencing (RNA-Seq) technique could be utilized to compare the transcription groups of two different cold-resistant rapeseed leaves responding to low temperature at the seedling stage, analyze the photosynthetic characteristics of rapeseed subjected to low temperature stress, and identify the related genes for low temperature induction in rapeseed leaves. Results Using cold-tolerant variety 17NS and sensitive variety NF24 as experimental materials, carrying out RNA-Seq analysis by photosynthetic parameter determination and Illumina HiSeqTM platform. and screen out the KEGG significant enrichment pathway related to photosynthetic characteristics under low temperature stress. Differential Expressed Genes (DEGs) were used for real-time PCR to verify the reliability of RNA-Seq results. The results showed that the response of Brassica napus L. to low temperature stress mainly was achieved by inhibiting photosynthesis, the cold-tolerant variety 17NS had a strong ability to maintain membrane system stability and structural integrity after 24 h of low temperature stress, while the sensitive variety NF24 photosynthesis was significantly inhibited. Two pathways of Photosynthesis and Photosynthesis-antennas, which were significantly correlated with photosynthetic characteristics and low temperature stress were screened by KEGG enrichment. The results of DEGs indicated that 64 differentially expressed genes in these two pathways were induced by low temperature stress, and 8 of them were up-regulated expression and 56 of them were down-regulated expression. The expression pattern of DEGs was consistent with the results of RNA-Seq analysis by qRT-PCR detection and confirmed the reliability of RNA-Seq results. Conclusion Our study analysis and identified 17 low-temperature-induced photosynthetic-related candidate genes in Brassica napus L., and the GO and KEGG metabolic pathways clarified the molecular function of differentially expressed genes.

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Gene-Coexpression Network Analysis Identifies Specific Modules and Hub Genes Related to Cold Stress in Rice

10.21203/rs.3.rs-737261/v1 ◽

2021 ◽

Author(s):

Zhichi Zeng ◽

Sichen Zhang ◽

Wenyan Li ◽

Baoshan Chen ◽

Wenlan Li

Keyword(s):

Network Analysis ◽

Low Temperature ◽

Cold Stress ◽

Cold Tolerance ◽

Temperature Stress ◽

Low Temperature Stress ◽

Rice Cultivars ◽

Hub Genes ◽

New Genes ◽

Short Period

Abstract Background: When plants are subjected to cold stress, they undergo a series of molecular and physiological changes to protect themselves from injury. Indica cultivars can usually withstand only mild cold stress in a relatively short period. Hormone-mediated defence response plays an important role in cold stress. Weighted gene co-expression network analysis (WGCNA) is a very useful tool for studying the correlation between genes, identifying modules with high phenotype correlation, and identifying Hub genes in different modules. Many studies have elucidated the molecular mechanisms of cold tolerance in different plants, but little information about the recovery process after cold stress is available.Results: To understand the molecular mechanism of cold tolerance in rice, we performed comprehensive transcriptome analyses during cold treatment and recovery stage in two cultivars of near-isogenic lines (9311 and DC907). Twelve transcriptomes in two rice cultivars were determined. A total of 2509 new genes were predicted by fragment splicing and assembly, and 7506 differentially expressed genes were identified by pairwise comparison. A total of 26 modules were obtained by expression-network analysis, 12 of which were highly correlated with cold stress or recovery treatment. We further identified candidate Hub genes associated with specific modules and analysed their regulatory relationships based on coexpression data. Results showed that various plant-hormone regulatory genes acted together to protect plants from physiological damage under short-term low-temperature stress. We speculated that this may be common in rice. Under long-term cold stress, rice improved the tolerance to low-temperature stress by promoting autophagy, sugar synthesis, and metabolism.Conclusion: Through WGCNA analysis at the transcriptome level, we provided a potential regulatory mechanism for the cold stress and recovery of rice cultivars and identified candidate central genes. Our findings provided an important reference for the future cultivation of rice strains with good tolerance.

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Genome-Wide Association Mapping Unravels the Genetic Control of Seed Vigor under Low-Temperature Conditions in Rapeseed (Brassica napus L.)

Plants ◽

10.3390/plants10030426 ◽

2021 ◽

Vol 10 (3) ◽

pp. 426

Author(s):

Tao Luo ◽

Yuting Zhang ◽

Chunni Zhang ◽

Matthew N. Nelson ◽

Jinzhan Yuan ◽

...

Keyword(s):

Low Temperature ◽

Stress Tolerance ◽

Candidate Genes ◽

Temperature Stress ◽

Seed Vigor ◽

Low Temperature Stress ◽

Brassica Napus L ◽

Temperature Conditions ◽

Genome Wide ◽

Tolerance Indices

Low temperature inhibits rapid germination and successful seedling establishment of rapeseed (Brassica napus L.), leading to significant productivity losses. Little is known about the genetic diversity for seed vigor under low-temperature conditions in rapeseed, which motivated our investigation of 13 seed germination- and emergence-related traits under normal and low-temperature conditions for 442 diverse rapeseed accessions. The stress tolerance index was calculated for each trait based on performance under non-stress and low-temperature stress conditions. Principal component analysis of the low-temperature stress tolerance indices identified five principal components that captured 100% of the seedling response to low temperature. A genome-wide association study using ~8 million SNP (single-nucleotide polymorphism) markers identified from genome resequencing was undertaken to uncover the genetic basis of seed vigor related traits in rapeseed. We detected 22 quantitative trait loci (QTLs) significantly associated with stress tolerance indices regarding seed vigor under low-temperature stress. Scrutiny of the genes in these QTL regions identified 62 candidate genes related to specific stress tolerance indices of seed vigor, and the majority were involved in DNA repair, RNA translation, mitochondrial activation and energy generation, ubiquitination and degradation of protein reserve, antioxidant system, and plant hormone and signal transduction. The high effect variation and haplotype-based effect of these candidate genes were evaluated, and high priority could be given to the candidate genes BnaA03g40290D, BnaA06g07530D, BnaA09g06240D, BnaA09g06250D, and BnaC02g10720D in further study. These findings should be useful for marker-assisted breeding and genomic selection of rapeseed to increase seed vigor under low-temperature stress.

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