油茶响应不同光照强度的转录组分析

Transcriptome analysis of Camellia oleifera in response to different light intensities

  • 摘要: 【目的】对油茶不同光照强度条件下的转录组进行测序分析,以期解析油茶响应光照环境变化的分子调控网络,为油茶高光效代谢网络构建及其关键基因挖掘提供依据。【方法】在不同光照强度处理下测定油茶叶片光合生理指标,利用高通量测序技术进行转录组测序分析,挖掘光合作用、初级代谢、次级代谢、激素合成相关通路上的差异表达基因(DEGs),并分析其表达特征。【结果】随光照强度减弱,油茶叶片净光合速率、气孔导度和碳含量降低,而胞间CO2浓度、叶绿素a、叶绿素b和氮素含量提高。GO功能注释结果显示,油茶通过上调生物学过程、细胞组成和分子功能相关DEGs的表达来适应弱光环境。Mapman代谢通路富集结果显示,油茶通过上调捕光复合体、电子传递蛋白、碳水化合物分解和氮代谢,下调光呼吸和三羧酸循环通路上DEGs的表达以应对碳同化能力的不足。随光照强度降低,脱落酸(ABA)、油菜素内酯(BR)、生长素(IAA)、茉莉酸(JA)和赤霉素(GA)合成通路上的DEGs上调表达,分裂素(CTK)分解通路上的DEGs下调表达,黄酮类、苯丙烷类、酚类、萜类、生物碱等次级代谢通路上的DEGs下调表达。共鉴定出1372个转录因子,其中家族成员数量最多的转录因子为bHLH和ERF,分别有115个和100个。【结论】油茶光合碳同化能力随光照强度降低而下降。在分子水平上通过上调捕光复合体、电子传递蛋白、碳水化合物分解、氮代谢和各类激素合成,下调呼吸作用和次级代谢途径上的基因表达,以及调控bHLH和ERF两大类转录因子来响应低光照强度环境。

     

    Abstract: 【Objective】To analyze the molecular regulatory network of Camellia oleifera in response to changes in light intensity environment,and provide a basis for the construction of high-light-efficiency metabolic network and the mining of key genes in Camellia oleifera,this study analyzed the transcriptome sequencing of C. oleifera in response to different light intensities.【Method】 The photosynthetic physiological indexes of C. oleifera leaves were determined under different light intensities. And transcriptome sequencing was performed using high-throughput sequencing technology, and the differentially expressed genes(DEGs)in the pathways related to photosynthesis,primary metabolism,secondary metabolism and hormone synthesis were discovered and their expression characteristics were analyzed.【Result】 With the decrease of light intensity,the net photosynthetic rate,stomatal conductance and carbon content of C. oleifera leaves decreased,while the intercellular CO2 concentration,chlorophyll a,chlorophyll b and nitrogen contents increased. GO function annotation results showed that C. oleifera adapted to low light intensity environment by up-regulating the expression of DEGs related to biological process,cellular component and molecular function. Mapman metabolic pathway enrichment analysis showed that the C. oleifera up-regulated DEGs expression in light-harvesting complex,electron transport protein,carbohydrate decomposition and nitrogen metabolism pathways,and down-regulated DEGs expression in photorespiration and tricarboxylic acid cycle pathways to cope with the deficiency of carbon assimilation ability. With the decreasing of light intensity,the DEGs in abscisic acid(ABA),brassinolide(BR),auxin(IAA),jasmonic acid(JA) and gibberellin(GA)synthesis pathways were up-regulated,while the DEGs in mitogen(CTK)decomposition pathway were down-regulated. And the DEGs in flavonoids, phenylpropanoids, phenols, terpenoids, alkaloids and other secondary metabolic pathways were down-regulated. A total of 1372 transcription factors were identified,among which the largest number of family members were bHLH and ERF with 115 and 100 members,respectively.【Conclusion】The photosynthetic carbon assimilation ability of C. oleifera decreases with the decrease of light intensity. C. oleifera responds to low light intensity environment by up-regulating DEGs expression in light-harvesting complex,electron transport protein, carbohydrate decomposition,nitrogen metabolism and various types of hormone synthesis,and down-regulating DEGs expression in respiration and secondary metabolism,and regulating two major transcription factors,bHLH and ERF,at molecular level.

     

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