中国农业科学 ›› 2024, Vol. 57 ›› Issue (14): 2827-2846.doi: 10.3864/j.issn.0578-1752.2024.14.011

• 园艺 • 上一篇    下一篇

基于转录组学分析辣椒对磷营养逆境的响应

徐明睿(), 王晓娟, 杨亚莉, 马越飞, 刘万茂, 孙颖*()   

  1. 宁夏大学农学院,银川 750021
  • 收稿日期:2023-12-22 接受日期:2024-05-20 出版日期:2024-07-16 发布日期:2024-07-24
  • 通信作者:
    孙颖,E-mail:
  • 联系方式: 徐明睿,E-mail:xumingrui@stu.nxu.edu.cn。
  • 基金资助:
    宁夏自然科学基金(2022AAC03089); 宁夏重点研发项目(引才专项)(2021BEB04079)

Transcriptomics-Based Analysis of Pepper Responses to Phosphorus Nutritional Stress

XU MingRui(), WANG XiaoJuan, YANG YaLi, MA YueFei, LIU WanMao, SUN Ying*()   

  1. College of Agriculture, Ningxia University, Yinchuan 750021
  • Received:2023-12-22 Accepted:2024-05-20 Published:2024-07-16 Online:2024-07-24

摘要:

【目的】 探究辣椒幼苗在不同梯度磷胁迫下的转录水平及生理响应的变化,分析不同梯度磷胁迫的重要通路,并结合相关生理试验分析辣椒应对磷营养逆境的生理机制,筛选出调控磷营养逆境的转录因子及核心基因,为辣椒选育提供理论基础和基因资源。【方法】 本研究以纯系辣椒CA#8幼苗根系为试验材料,采用霍格兰水培法培养至四叶一心期进行4个不同梯度磷胁迫处理,分别为对照组(CK,200 μmol·L-1 NH4H2PO4)、缺磷胁迫组(DP,0 μmol·L-1 NH4H2PO4)、低磷胁迫组(LP,20 μmol·L-1 NH4H2PO4)和高磷胁迫组(HP,1 000 μmol·L-1 NH4H2PO4)。处理2 d后对辣椒根系进行转录组测序(RNA-Seq),并在处理0、2、4和6 d后测定辣椒根系内源激素和抗氧化酶活性。【结果】 与CK组对比,DP、LP、HP组的差异表达基因(DEG)分别为626、107、171个,通过GO、KEGG富集分析和WGCNA分析发现10个与磷信号途径相关的DEG,4个与植物激素信号转导途径相关的DEG,7个与抗氧化酶活性相关的DEG,并进行实时荧光定量(qRT-PCR)验证了转录组数据的准确性。对辣椒幼苗根系内源激素定量测定发现,随着磷胁迫时间的增加,与CK组对比,DP、LP、HP组幼苗根系内各种生长促进类的植物内源激素如赤霉素(GA)、油菜素内酯(BR)、细胞分裂素(CTK)、吲哚乙酸(IAA)、独脚金内酯(SL)、茉莉酸(JA)含量降低,生长抑制类激素如乙烯(ETH)、脱落酸(ABA)含量上升。其中,缺磷胁迫和低磷胁迫表现最为明显,对幼苗根系生长的抑制程度最大。不同梯度磷胁迫处理能够诱导辣椒组织中超氧化物歧化酶(SOD)、过氧化物酶(POD)、过氧化氢酶(CAT)活性升高,胁迫后期SOD活性下降,POD和CAT活性趋于稳定。【结论】 磷营养逆境下,辣椒通过响应磷信号途径、植物激素信号转导途径及抗氧化酶活性相关的差异表达基因,缓解了磷胁迫对辣椒幼苗生长的影响,增强了辣椒对磷胁迫的耐受性。

关键词: 辣椒, 磷胁迫, 磷饥饿响应, 转录组, 基因挖掘

Abstract:

【Objective】 This study aimed to explore the changes in the transcriptional level and physiological responses of pepper (Capsicum annuum L.) seedlings under different phosphorus stress gradients, to analyze the key pathways, and to integrate related experiments to elucidate the physiological mechanisms of the pepper response to nutritional stress of phosphorus. This study also identified the transcription factors and core genes that regulate the nutritional stress of phosphorus, so as to provide a theoretical basis and genetic resources for the breeding of peppers. 【Method】 This study used the roots of the pure CA#8 seedlings of pepper as experimental material, grown by Hoagland hydroponics in a single four-leaf stage and subjected to four different gradient phosphorus stress treatments, namely control group (CK, 200 μmol·L-1 NH4H2PO4) and phosphorus deficiency group (DP, 0 μmol·L-1 NH4H2PO4), low phosphorus stress group (LP, 20 μmol·L-1 NH4H2PO4), and high phosphorus stress group (HP, 1 000 μmol·L-1 NH4H2PO4). Transcriptome sequencing (RNA-Seq) was performed on pepper roots systems 2 days after treatment, and the endogenous hormone levels and antioxidant enzyme activities were measured after 0, 2, 4, and 6 days of treatment, respectively. 【Result】 Compared with the CK group, the DP, LP, and HP groups exhibited 626, 107, and 171 differentially expressed genes (DEG), respectively. 10 DEGs related to the phosphorus signaling pathway, 4 DEGs related to the plant hormone signal transduction pathway, and 7 DEGs related to antioxidant enzyme activities were identified by GO, KEGG enrichment analysis, and WGCNA analysis. Real-time fluorescence quantitative (qRT-PCR) was used to validate the accuracy of transcriptome data. Quantitative measurements of endogenous hormones in the roots of pepper seedlings showed that with increasing duration phosphorus stress, the levels of various growth-promoting endogenous hormones such as gibberellin (GA), brassinolide (BR), cytokinin (CTK), indole acetic acid (IAA), strigolactone (SL), and jasmonic acid (JA) decreased in the DP, LP and HP groups, while the levels of growth-inhibiting hormones such as ethylene (ETH) and abscisic acid (ABA) increased, especially under phosphorus deficiency and low phosphorus stress, where growth inhibition of the seedling roots was the most significant. Various phosphorus stress-induced increased activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT) in pepper root tissue, while the activities of SOD decreased at the later stage of stress, and POD and CAT tended to be stable too. 【Conclusion】 During various phosphorus nutritional stress, the pepper seedlings mitigated the effects of phosphorus stress on growth by responding to phosphorus signaling pathways, plant hormone signal transduction pathways, and differentially expressed genes related to antioxidant enzyme activity, thus improving the tolerance to phosphorus stress of pepper seedlings.

Key words: Capsicum annuum L., phosphorus stress, phosphorus starvation response, transcriptome, gene mining