Methyl-Sensitive Amplification Polymorphism (MSAP) Analysis Provides Insights into the DNA Methylation Underlying Heterosis in Kenaf (Hibiscus Cannabinus L.) Drought Tolerance

ABSTRACT

Kenaf (Hibiscus cannabinus L.) is an industrial fiber crop with significant heterosis and tolerance to abiotic stresses. However, the mechanism underlying heterosis in kenaf under drought conditions is completely unknown. In this study, F₁ hybrids were remarkably tolerant to drought stress. Through methylation-sensitive amplification polymorphism (MSAP) analysis, we highlighted that total DNA methylation level under drought decreased by 11.2% in F₁ and increased by 29.7% and 13.1% in parents CP079 and CP071, respectively. Unlike parents, the hypomethylation rate was 38% higher than hypermethylation in F₁, the overall change in methylation pattern was higher in F₁ (1.6%) than parents (0.4%). Furthermore, 35 key DNA fragments showing different methylation patterns were analyzed and found that the cytosine methylation status of DnaJ, ERF5, ZIP2, and PATL3 revealed changes in DNA methylation that may affect their respective expression level. Subsequently, virus-induced gene silencing (VIGS) mediated knockdown of the DnaJ, significantly increased the sensitivity of kenaf seedlings to drought. Overall, this study provides an epigenetic mechanism that could be used to improve the breeding strategy in kenaf.

摘要

红麻是一种工业纤维作物, 具有较强的杂种优势和对非生物胁迫的耐受性。然而, 红麻抗旱杂种优势的潜在机制还不清楚。在本研究中, 相对于其亲本, 红麻杂交种 (CP079×CP071) F₁在干旱胁迫下具有显著的杂种优势。 利用甲基化敏感扩增多态性 (MSAP) 分析正常和干旱条件下红麻叶片的DNA甲基化模式变化结果表明干旱条件下F₁的总DNA甲基化水平下降了11.2%, 而亲本CP079和CP071的总甲基化水平分别上升了29.7%和13.1%。与亲本不同, F₁中的的次甲基化率比超甲基化率高38%, 且DNA甲基化模式完全改变率 (1.6%) 高于亲本 (0.4%)。此外, 对35个甲基化模式发生变化的DNA片段进行了分析, 发现DnaJ, ERF5, ZIP2和PATL3的胞嘧啶甲基化状态的改变可能影响其表达水平的变化。随后, 本研究利用病毒诱导的基因沉默技术 (VIGS) 沉默DnaJ后, 可显著提高红麻幼苗对干旱的敏感性。总而言之, 本研究从DNA甲基化表观遗传角度揭示了红麻抗旱杂种优势机理, 为理解红麻抗旱杂种优势提供了新的见解。

KEYWORDS:

• Kenaf
• DNA methylation
• drought stress
• heterosis
• MSAP
• VIGS

关键词:

• 红麻
• DNA甲基化
• 干旱胁迫
• 杂种优势
• MSAP
• VIGS

Highlight

• F₁ is more tolerant to drought stress than parental lines (CP079 and CP071).

• Total DNA methylation level under drought conditions decreased in F₁ and increased in parents.

• Unlike parental cultivars, hypomethylation rate was higher than hypermethylation in F₁; the hypomethylation sites were lower in F₁ than the parents under control and increased under drought stress, indicating that heterosis was achieved by increasing hypomethylation and reducing hypermethylation in F₁.

• Among the 35 key DNA fragments with different methylation patterns that have been cloned and sequenced, the relative expression and cytosine methylation status of DnaJ, ERF5, ZIP2, and PATL3 revealed changes in DNA methylation, which may affect their expression level.

• VIGS analysis suggested DnaJ gene positively regulates the drought resistance in kenaf by increasing antioxidant enzyme activity.

Acknowledgments

Authors are thankful for China hemp Research Institute and Guangxi Academy of Agricultural Sciences for providing seeds of kenaf cultivar CP071 and CP079, respectively.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/15440478.2022.2103610.

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This research work was supported by:The National Natural Science Foundation of China [31960368];China Agricultural Research System of MOF and MARA [CARS-16-E14];Innovation Project of Guangxi Graduate Education [YCBZ2020015]; The National Science Foundation of ChinaThe National Science Foundation of China [31960368];