比较转录组学和生理学分析揭示脱落酸在绣球花响应炭疽病菌中的关键作用。

Comparative transcriptomic and physiological analyses reveal the key role of abscisic acid in hydrangea macrophylla responding to Corynespora cassiicola.

机构信息

Jiangsu Provincial Key Laboratory for Horticultural Crop Genetics and Improvement, Institute of Leisure Agriculture, Jiangsu Academy of Agricultural Sciences, Nanjing, 210014, China.

School of Architecture and Engineering, Anhui University of Technology, Maanshan, 243032, China.

出版信息

BMC Plant Biol. 2024 Nov 12;24(1):1066. doi: 10.1186/s12870-024-05770-6.

DOI:10.1186/s12870-024-05770-6

PMID:39533189

原文链接:https://pmc.ncbi.nlm.nih.gov/articles/PMC11555933/

Abstract

BACKGROUND

Bigleaf hydrangea (Hydrangea macrophylla) is a widely cultivated ornamental plant species. Leaf spot disease, caused by Corynespora cassiicola, poses a significant threat to the ornamental quality and economic value of hydrangeas. However, the disease resistance breeding of hydrangea is limited due to the lacking of resistant varieties and genes.

RESULTS

This study evaluated ten hydrangea varieties for their resistance to leaf spot disease. Among them, 'White Angel' and 'Ocean Heart' were screened out as representative varieties for resistance and susceptibility, respectively, on the basis of evaluation. Physiological and biochemical indices, phytohormones, and transcriptomic changes were measured in the leaves of both varieties at 0 and 24 h post inoculation with C. cassiicola. The results showed that C. cassiicola infection significantly increased abscisic acid (ABA) contents in both varieties; however, the increase was significantly higher in the susceptible variety 'Ocean Heart' compared to the resistant variety 'White Angel' (p < 0.05). Moreover, exogenous ABA (100 µM) decreased the leaves' resistance to C. cassiicola of both varieties, underscoring its key role in reduced disease resistance. Transcriptome profiling revealed 17,087 differentially expressed genes (DEGs) responding to C. cassiicola between the two varieties. Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis indicated significant enrichment of DEGs in "Plant hormone signal transduction", particularly related to ABA signaling (HmPP2C and HmABFs). In addition, the expression of ABA biosynthesis genes (HmZEP3, HmABA2, and HmAAO3) was upregulated in both varieties. Meanwhile, the ABA catabolism gene (HmCYP707A4) exhibited significantly upregulated expression in the resistant variety 'White Angel' and downregulated expression in the susceptible variety 'Ocean Heart'. Intriguingly, the expression of HmCYP707A4 was 15-fold higher in 'White Angel' than in 'Ocean Heart'.

CONCLUSION

In summary, these findings highlight the crucial role of ABA in the resistance of bigleaf hydrangea to leaf spot disease and provide valuable genetic resources for breeding programs to enhance the disease resistance in hydrangeas.

摘要

背景

绣球花（Hydrangea macrophylla）是一种广泛栽培的观赏植物。炭疽病是由胶孢炭疽菌引起的，严重威胁着绣球花的观赏品质和经济价值。然而，由于缺乏抗性品种和基因，绣球花的抗病性育种受到限制。

结果

本研究评估了 10 个绣球花品种对叶斑病的抗性。在此基础上，筛选出‘White Angel’和‘Ocean Heart’分别为抗病性和感病性的代表品种。在接种胶孢炭疽菌后 0 和 24 h 测量了两个品种叶片的生理生化指标、植物激素和转录组变化。结果表明，胶孢炭疽菌感染显著增加了两个品种叶片中的脱落酸（ABA）含量；然而，感病品种‘Ocean Heart’的增加显著高于抗病品种‘White Angel’（p<0.05）。此外，外源 ABA（100 μM）降低了两个品种叶片对胶孢炭疽菌的抗性，这表明 ABA 在降低抗病性方面起着关键作用。转录组分析揭示了两个品种之间对胶孢炭疽菌响应的 17087 个差异表达基因（DEGs）。京都基因与基因组百科全书（KEGG）分析表明，DEGs 在“植物激素信号转导”中显著富集，特别是与 ABA 信号转导相关（HmPP2C 和 HmABFs）。此外，ABA 生物合成基因（HmZEP3、HmABA2 和 HmAAO3）在两个品种中均上调表达。同时，ABA 分解代谢基因（HmCYP707A4）在抗病品种‘White Angel’中表达显著上调，而在感病品种‘Ocean Heart’中表达下调。有趣的是，‘White Angel’中 HmCYP707A4 的表达量比‘Ocean Heart’高 15 倍。