比较转录组分析揭示了高、低糖芥芽在热应激反应中的差异。
Comparative transcriptome analyses revealed different heat stress responses in high- and low-GS Brassica alboglabra sprouts.
机构信息
Joint FAFU-Dalhousie Lab, College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
College of Horticulture, Fujian Agriculture and Forestry University, Fuzhou, 350002, China.
出版信息
BMC Genomics. 2019 Apr 4;20(1):269. doi: 10.1186/s12864-019-5652-y.
BACKGROUND
Chinese kale (Brassica alboglabra) contains high nutritional elements and functional molecules, especially anticarcinogenic and antioxidant glucosinolates (GS), which was highly affected by environment temperature. To investigate the link of GS biosynthesis with heat stress response in Chinese kale, global transcription profiles of high-GS line (HG), low-GS line (LG), high-GS line under heat stress (HGT) and low-GS line under heat stress (LGT) were analyzed.
RESULTS
Based on three biological replicates of each RNA sequencing data, 3901, 4062 and 2396 differentially expressed genes in HG vs HGT, LG vs LGT and HGT vs LGT were obtained, respectively. GO annotation, KEGG pathway analysis and a comprehensive analysis of DEGs showed a strong correlation between the GS biosynthesis and heat stress response. It was noticed that 11 differentially expressed genes tied to the GS biosynthesis were down-regulated, 23 heat shock transcription factors and 61 heat shock proteins were up-regulated upon the heat treatment. Another two Chinese kale varieties Cuibao and Shunbao with high- and low- GS content respectively, were used to validate the relationship of GS content and heat-response, and the results showed that high-GS content variety were more thermotolerant than the low-GS content one although GS significantly decreased in both varieties under heat stress. In addition, HSP100/ClpB, HSP90, HSP70 and sHSPs were differentially expressed in high- and low-GS varieties. Notably, HSP90 and sHSPs showed an obviously early response to heat stress than other related genes.
CONCLUSION
The higher heat resistance of high-GS Chinese kale and the sharp decrease of glucosinolate content under heat stress indicated a strong relationship of GS accumulation and heat stress response. Combined with the previous report on the low expression of HSP90 at elevated temperatures in GS-deficient mutant TU8 of Arabidopsis, the differential expression pattern of HSP90 in high- and low- GS varieties and its early heat response implied it might be a key regulator in GS metabolism and heat-resistance in Chinese kale.
背景
芥蓝（Brassica alboglabra）含有丰富的营养成分和功能分子，尤其是具有抗癌和抗氧化作用的硫代葡萄糖苷（GS），其含量受环境温度影响较大。为研究 GS 生物合成与芥蓝耐热性的关系，对高 GS 品系（HG）、低 GS 品系（LG）、热胁迫下高 GS 品系（HGT）和热胁迫下低 GS 品系（LGT）的转录组进行了分析。
结果
基于每个 RNA 测序数据的三个生物学重复，分别在 HG 与 HGT、LG 与 LGT 和 HGT 与 LGT 之间获得了 3901、4062 和 2396 个差异表达基因。GO 注释、KEGG 通路分析和 DEGs 的综合分析表明，GS 生物合成与热胁迫反应之间存在很强的相关性。值得注意的是，与 GS 生物合成相关的 11 个差异表达基因下调，23 个热激转录因子和 61 个热激蛋白上调。另外两个 GS 含量高低不同的芥蓝品种翠宝和顺宝，用于验证 GS 含量与热响应的关系，结果表明，高 GS 含量品种比低 GS 含量品种更耐热，尽管在热胁迫下两个品种的 GS 含量都显著下降。此外，高、低 GS 品种中 HSP100/ClpB、HSP90、HSP70 和 sHSPs 表达不同。值得注意的是，HSP90 和 sHSPs 对热胁迫的反应明显早于其他相关基因。
结论
高 GS 芥蓝的耐热性较高，GS 含量在热胁迫下急剧下降，表明 GS 积累与热胁迫反应密切相关。结合先前报道的拟南芥 GS 缺失突变体 TU8 在温度升高时 HSP90 表达较低的研究结果，HSP90 在高、低 GS 品种中的差异表达模式及其对热胁迫的早期反应表明，它可能是 GS 代谢和耐热性的关键调节因子。
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