Comparative analysis of rapid alkalinization factor peptide-triggered plant immunity in citrus and closely related species

IF 6.1 2区生物学 Q1 PLANT SCIENCES

Plant Physiology and Biochemistry Pub Date : 2025-04-21 DOI:10.1016/j.plaphy.2025.109941

Wenzhong Shen , Mengying Yuan , Lijuan Chen , Xinxin Zhang

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引用次数: 0

Abstract

Rapid alkalinization factors (RALFs) are plant-derived, cysteine-rich small peptides that play crucial roles in plant development and immunity. However, their function in citrus immunity remains unexplored. This study systematically identified RALF family members in sweet orange, a cultivated citrus species, and five closely related species known for their strong resistance to citrus diseases. Most species contained 13 RALF genes, and their corresponding RALF orthologs exhibited minimal variation in gene structure, sequence identity, conserved domains, and motifs. However, differences in cis-acting elements within promoter regions led to differences in their expression patterns under biotic stress. Compared with sweet orange, citrus-related species exhibited a stronger and more widespread induction of RALF genes. Additionally, RALF peptides, particularly RALF11, triggered more robust immune responses in these species, including ROS bursts, mitogen-activated protein kinase activation, and the upregulation of defense-related genes. Furthermore, the basal expression levels of CrRLK1Ls, the RALF receptor homologs, were higher in citrus-related species than in sweet orange. Amplifying the RALF-CrRLK1L pathway through CrRLK1L overexpression and RALF peptide application significantly enhanced sweet orange resistance to citrus canker. These findings suggest that citrus-related species have endured selective pressure, leading to greater promoter sequence diversity, which is conducive to fine-tune gene expression in response to environmental challenges.

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柑桔及其近缘种快速碱化因子肽触发植物免疫的比较分析

快速碱化因子（ralf）是源自植物的富含半胱氨酸的小肽，在植物发育和免疫中起着至关重要的作用。然而，它们在柑橘免疫中的功能仍未被探索。本研究系统地鉴定了甜橙（一种栽培柑橘品种）和5个具有较强抗病能力的近缘品种的RALF家族成员。大多数物种含有13个RALF基因，其相应的RALF同源基因在基因结构、序列同一性、保守结构域和基序方面变化最小。然而，启动子区域内顺式作用元件的差异导致了它们在生物胁迫下表达模式的差异。与甜橙相比，柑橘近缘种对RALF基因的诱导作用更强、更广泛。此外，RALF肽，特别是RALF11，在这些物种中引发了更强大的免疫反应，包括ROS爆发、丝裂原激活的蛋白激酶激活和防御相关基因的上调。此外，CrRLK1Ls （RALF受体同源物）的基础表达水平在柑橘相关物种中高于甜橙。通过CrRLK1L过表达和使用RALF肽扩增RALF-CrRLK1L通路，显著增强甜橙对柑橘溃疡病的抗性。这些发现表明，柑橘相关物种承受了选择压力，导致启动子序列更大的多样性，这有利于微调基因表达以应对环境挑战。

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来源期刊

Plant Physiology and Biochemistry 生物-植物科学

CiteScore

11.10

自引率

3.10%

发文量

410

审稿时长

33 days

期刊介绍： Plant Physiology and Biochemistry publishes original theoretical, experimental and technical contributions in the various fields of plant physiology (biochemistry, physiology, structure, genetics, plant-microbe interactions, etc.) at diverse levels of integration (molecular, subcellular, cellular, organ, whole plant, environmental). Opinions expressed in the journal are the sole responsibility of the authors and publication does not imply the editors'' agreement. Manuscripts describing molecular-genetic and/or gene expression data that are not integrated with biochemical analysis and/or actual measurements of plant physiological processes are not suitable for PPB. Also "Omics" studies (transcriptomics, proteomics, metabolomics, etc.) reporting descriptive analysis without an element of functional validation assays, will not be considered. Similarly, applied agronomic or phytochemical studies that generate no new, fundamental insights in plant physiological and/or biochemical processes are not suitable for publication in PPB. Plant Physiology and Biochemistry publishes several types of articles: Reviews, Papers and Short Papers. Articles for Reviews are either invited by the editor or proposed by the authors for the editor''s prior agreement. Reviews should not exceed 40 typewritten pages and Short Papers no more than approximately 8 typewritten pages. The fundamental character of Plant Physiology and Biochemistry remains that of a journal for original results.