MDPI - Publisher of Open Access Journals

15 pages, 2936 KiB

Open AccessArticle

Arabidopsis RALF4 Rapidly Halts Pollen Tube Growth by Increasing ROS and Decreasing Calcium Cytoplasmic Tip Levels

by Sofía C. Somoza, Noelia A. Boccardo, Franco Santin, Ana R. Sede, Diego L. Wengier, Aurélien Boisson-Dernier and Jorge P. Muschietti

Biomolecules 2024, 14(11), 1375; https://doi.org/10.3390/biom14111375 - 29 Oct 2024

Cited by 2 | Viewed by 1598

Abstract

In recent years, the rapid alkalinization factor (RALF) family of cysteine-rich peptides has been reported to be crucial for several plant signaling mechanisms, including cell growth, plant immunity and fertilization. RALF4 and RALF19 (RALF4/19) pollen peptides redundantly regulate the pollen tube integrity and [...] Read more.

In recent years, the rapid alkalinization factor (RALF) family of cysteine-rich peptides has been reported to be crucial for several plant signaling mechanisms, including cell growth, plant immunity and fertilization. RALF4 and RALF19 (RALF4/19) pollen peptides redundantly regulate the pollen tube integrity and growth through binding to their receptors ANXUR1/2 (ANX1/2) and Buddha’s Paper Seal 1 and 2 (BUPS1/2), members of the Catharanthus roseus RLK1-like (CrRLK1L) family, and, thus, are essential for plant fertilization. However, the signaling mechanisms at the cellular level that follow these binding events remain unclear. In this study, we show that the addition of synthetic peptide RALF4 rapidly halts pollen tube growth along with the excessive deposition of plasma membrane and cell wall material at the tip. The ratiometric imaging of genetically encoded ROS and Ca²⁺ sensors-expressing pollen tubes shows that RALF4 treatment modulates the cytoplasmic levels of reactive oxygen species (ROS) and calcium (Ca²⁺) in opposite ways at the tip. Thus, we propose that pollen RALF4/19 peptides bind ANX1/2 and BUPS1/2 to regulate ROS and calcium homeostasis to ensure proper cell wall integrity and control of pollen tube growth. Full article

(This article belongs to the Special Issue Molecular Plant Reproduction: From Cells to Nature)

► Show Figures

Figure 1

16 pages, 6874 KiB

Open AccessArticle

Genome-Wide Identification of the RALF Gene Family and Expression Pattern Analysis in Zea mays (L.) under Abiotic Stresses

by Baoping Xue, Zicong Liang, Yue Liu, Dongyang Li and Chang Liu

Plants 2024, 13(20), 2883; https://doi.org/10.3390/plants13202883 - 15 Oct 2024

Cited by 3 | Viewed by 1813

Abstract

Rapid Alkalization Factor (RALF) is a signaling molecule in plants that plays a crucial role in growth and development, reproductive processes, and responses to both biotic and abiotic stresses. Although RALF peptides have been characterized in Arabidopsis and rice, a comprehensive bioinformatics analysis [...] Read more.

Rapid Alkalization Factor (RALF) is a signaling molecule in plants that plays a crucial role in growth and development, reproductive processes, and responses to both biotic and abiotic stresses. Although RALF peptides have been characterized in Arabidopsis and rice, a comprehensive bioinformatics analysis of the ZmRALF gene family in maize is still lacking. In this study, we identified 20 RALF genes in the maize genome. Sequence alignment revealed significant structural variation among the ZmRALF family genes. Phylogenetic analysis indicates that RALF proteins from Arabidopsis, rice, and maize can be classified into four distinct clades. Duplication events suggest that the expansion of the RALF gene family in maize primarily relies on whole-genome duplication. ZmRALF genes are widely expressed across various tissues; ZmRALF1/15/18/19 are highly expressed in roots, while ZmRALF6/11/14/16 are predominantly expressed in anthers. RNA-seq and RT-qPCR demonstrated that the expression levels of ZmRALF7, ZmRALF9, and ZmRALF13 were significantly up-regulated and down-regulated in response to PEG and NaCl stresses, respectively. Overall, our study provides new insights into the role of the RALF gene family in abiotic stress. Full article

(This article belongs to the Collection Exploration and Application of Useful Agricultural Genes)

► Show Figures

Figure 1

26 pages, 4770 KiB

Open AccessArticle

A Rapid Alkalinization Factor-like Peptide EaF82 Impairs Tapetum Degeneration during Pollen Development through Induced ATP Deficiency

by Chiu-Yueh Hung, Farooqahmed S. Kittur, Keely N. Wharton, Makendra L. Umstead, D’Shawna B. Burwell, Martinique Thomas, Qi Qi, Jianhui Zhang, Carla E. Oldham, Kent O. Burkey, Jianjun Chen and Jiahua Xie

Cells 2023, 12(11), 1542; https://doi.org/10.3390/cells12111542 - 4 Jun 2023

Cited by 4 | Viewed by 3963

Abstract

In plants, the timely degeneration of tapetal cells is essential for providing nutrients and other substances to support pollen development. Rapid alkalinization factors (RALFs) are small, cysteine-rich peptides known to be involved in various aspects of plant development and growth, as well as [...] Read more.

In plants, the timely degeneration of tapetal cells is essential for providing nutrients and other substances to support pollen development. Rapid alkalinization factors (RALFs) are small, cysteine-rich peptides known to be involved in various aspects of plant development and growth, as well as defense against biotic and abiotic stresses. However, the functions of most of them remain unknown, while no RALF has been reported to involve tapetum degeneration. In this study, we demonstrated that a novel cysteine-rich peptide, EaF82, isolated from shy-flowering ‘Golden Pothos’ (Epipremnum aureum) plants, is a RALF-like peptide and displays alkalinizing activity. Its heterologous expression in Arabidopsis delayed tapetum degeneration and reduced pollen production and seed yields. RNAseq, RT-qPCR, and biochemical analyses showed that overexpression of EaF82 downregulated a group of genes involved in pH changes, cell wall modifications, tapetum degeneration, and pollen maturation, as well as seven endogenous Arabidopsis RALF genes, and decreased proteasome activity and ATP levels. Yeast two-hybrid screening identified AKIN10, a subunit of energy-sensing SnRK1 kinase, as its interacting partner. Our study reveals a possible regulatory role for RALF peptide in tapetum degeneration and suggests that EaF82 action may be mediated through AKIN10 leading to the alteration of transcriptome and energy metabolism, thereby causing ATP deficiency and impairing pollen development. Full article

(This article belongs to the Special Issue Plant, Algae and Fungi Cell Biology: State-of-the-Art and Perspectives)

► Show Figures

Figure 1

18 pages, 4327 KiB

Open AccessArticle

Genome-Wide Identification and Comparative Analysis of RALF Gene Family in Legume and Non-Legume Species

by Yancui Jia and Youguo Li

Int. J. Mol. Sci. 2023, 24(10), 8842; https://doi.org/10.3390/ijms24108842 - 16 May 2023

Cited by 8 | Viewed by 3155

Abstract

Rapid alkalinization factor (RALF) are small secreted peptide hormones that can induce rapid alkalinization in a medium. They act as signaling molecules in plants, playing a critical role in plant development and growth, especially in plant immunity. Although the function of RALF peptides [...] Read more.

Rapid alkalinization factor (RALF) are small secreted peptide hormones that can induce rapid alkalinization in a medium. They act as signaling molecules in plants, playing a critical role in plant development and growth, especially in plant immunity. Although the function of RALF peptides has been comprehensively analyzed, the evolutionary mechanism of RALFs in symbiosis has not been studied. In this study, 41, 24, 17 and 12 RALFs were identified in Arabidopsis, soybean, Lotus and Medicago, respectively. A comparative analysis including the molecular characteristics and conserved motifs suggested that the RALF pre-peptides in soybean represented a higher value of isoelectric point and more conservative motifs/residues composition than other species. All 94 RALFs were divided into two clades according to the phylogenetic analysis. Chromosome distribution and synteny analysis suggested that the expansion of the RALF gene family in Arabidopsis mainly depended on tandem duplication, while segment duplication played a dominant role in legume species. The expression levels of most RALFs in soybean were significantly affected by the treatment of rhizobia. Seven GmRALFs are potentially involved in the release of rhizobia in the cortex cells. Overall, our research provides novel insights into the understanding of the role of the RALF gene family in nodule symbiosis. Full article

(This article belongs to the Section Molecular Plant Sciences)

► Show Figures

Figure 1

25 pages, 7245 KiB

Open AccessArticle

Lateral Root Initiation in Cucumber (Cucumis sativus): What Does the Expression Pattern of Rapid Alkalinization Factor 34 (RALF34) Tell Us?

by Alexey S. Kiryushkin, Elena L. Ilina, Elizaveta D. Guseva, Katharina Pawlowski and Kirill N. Demchenko

Int. J. Mol. Sci. 2023, 24(9), 8440; https://doi.org/10.3390/ijms24098440 - 8 May 2023

Cited by 7 | Viewed by 3138

Abstract

In Arabidopsis, the small signaling peptide (peptide hormone) RALF34 is involved in the gene regulatory network of lateral root initiation. In this study, we aimed to understand the nature of the signals induced by RALF34 in the non-model plant cucumber (Cucumis sativus [...] Read more.

In Arabidopsis, the small signaling peptide (peptide hormone) RALF34 is involved in the gene regulatory network of lateral root initiation. In this study, we aimed to understand the nature of the signals induced by RALF34 in the non-model plant cucumber (Cucumis sativus), where lateral root primordia are induced in the apical meristem of the parental root. The RALF family members of cucumber were identified using phylogenetic analysis. The sequence of events involved in the initiation and development of lateral root primordia in cucumber was examined in detail. To elucidate the role of the small signaling peptide CsRALF34 and its receptor CsTHESEUS1 in the initial stages of lateral root formation in the parental root meristem in cucumber, we studied the expression patterns of both genes, as well as the localization and transport of the CsRALF34 peptide. CsRALF34 is expressed in all plant organs. CsRALF34 seems to differ from AtRALF34 in that its expression is not regulated by auxin. The expression of AtRALF34, as well as CsRALF34, is regulated in part by ethylene. CsTHESEUS1 is expressed constitutively in cucumber root tissues. Our data suggest that CsRALF34 acts in a non-cell-autonomous manner and is not involved in lateral root initiation in cucumber. Full article

(This article belongs to the Special Issue Meristem and Stem Cells and Stem Cell Regulation in Plants)

► Show Figures

Graphical abstract

28 pages, 7434 KiB

Open AccessArticle

Integrative Proteomics and Metabolomics Analysis Reveals the Role of Small Signaling Peptide Rapid Alkalinization Factor 34 (RALF34) in Cucumber Roots

by Julia Shumilina, Alexey S. Kiryushkin, Nadezhda Frolova, Valeria Mashkina, Elena L. Ilina, Vera A. Puchkova, Katerina Danko, Svetlana Silinskaya, Evgeny B. Serebryakov, Alena Soboleva, Tatiana Bilova, Anastasia Orlova, Elizaveta D. Guseva, Egor Repkin, Katharina Pawlowski, Andrej Frolov and Kirill N. Demchenko

Int. J. Mol. Sci. 2023, 24(8), 7654; https://doi.org/10.3390/ijms24087654 - 21 Apr 2023

Cited by 12 | Viewed by 4453

Abstract

The main role of RALF small signaling peptides was reported to be the alkalization control of the apoplast for improvement of nutrient absorption; however, the exact function of individual RALF peptides such as RALF34 remains unknown. The Arabidopsis RALF34 (AtRALF34) peptide [...] Read more.

The main role of RALF small signaling peptides was reported to be the alkalization control of the apoplast for improvement of nutrient absorption; however, the exact function of individual RALF peptides such as RALF34 remains unknown. The Arabidopsis RALF34 (AtRALF34) peptide was proposed to be part of the gene regulatory network of lateral root initiation. Cucumber is an excellent model for studying a special form of lateral root initiation taking place in the meristem of the parental root. We attempted to elucidate the role of the regulatory pathway in which RALF34 is a participant using cucumber transgenic hairy roots overexpressing CsRALF34 for comprehensive, integrated metabolomics and proteomics studies, focusing on the analysis of stress response markers. CsRALF34 overexpression resulted in the inhibition of root growth and regulation of cell proliferation, specifically in blocking the G2/M transition in cucumber roots. Based on these results, we propose that CsRALF34 is not part of the gene regulatory networks involved in the early steps of lateral root initiation. Instead, we suggest that CsRALF34 modulates ROS homeostasis and triggers the controlled production of hydroxyl radicals in root cells, possibly associated with intracellular signal transduction. Altogether, our results support the role of RALF peptides as ROS regulators. Full article

(This article belongs to the Special Issue Meristem and Stem Cells and Stem Cell Regulation in Plants)

► Show Figures

Graphical abstract

21 pages, 2148 KiB

Open AccessReview

Molecular Mechanisms of Regulation of Root Development by Plant Peptides

by Larisa I. Fedoreyeva

Plants 2023, 12(6), 1320; https://doi.org/10.3390/plants12061320 - 14 Mar 2023

Cited by 6 | Viewed by 4265

Abstract

Peptides perform many functions, participating in the regulation of cell differentiation, regulating plant growth and development, and also involved in the response to stress factors and in antimicrobial defense. Peptides are an important class biomolecules for intercellular communication and in the transmission of [...] Read more.

Peptides perform many functions, participating in the regulation of cell differentiation, regulating plant growth and development, and also involved in the response to stress factors and in antimicrobial defense. Peptides are an important class biomolecules for intercellular communication and in the transmission of various signals. The intercellular communication system based on the ligand-receptor bond is one of the most important molecular bases for creating complex multicellular organisms. Peptide-mediated intercellular communication plays a critical role in the coordination and determination of cellular functions in plants. The intercellular communication system based on the receptor-ligand is one of the most important molecular foundations for creating complex multicellular organisms. Peptide-mediated intercellular communication plays a critical role in the coordination and determination of cellular functions in plants. The identification of peptide hormones, their interaction with receptors, and the molecular mechanisms of peptide functioning are important for understanding the mechanisms of both intercellular communications and for regulating plant development. In this review, we drew attention to some peptides involved in the regulation of root development, which implement this regulation by the mechanism of a negative feedback loop. Full article

(This article belongs to the Special Issue Peptides in Plants)

► Show Figures

Figure 1

20 pages, 3851 KiB

Open AccessArticle

The Phaseolus vulgaris Receptor-Like Kinase PvFER1 and the Small Peptides PvRALF1 and PvRALF6 Regulate Nodule Number as a Function of Nitrate Availability

by Jorge Solís-Miranda, Marco A. Juárez-Verdayes, Noreide Nava, Paul Rosas, Alfonso Leija-Salas, Luis Cárdenas and Carmen Quinto

Int. J. Mol. Sci. 2023, 24(6), 5230; https://doi.org/10.3390/ijms24065230 - 9 Mar 2023

Cited by 12 | Viewed by 2926

Abstract

Legumes associate with Gram-negative soil bacteria called rhizobia, resulting in the formation of a nitrogen-fixing organ, the nodule. Nodules are an important sink for photosynthates for legumes, so these plants have developed a systemic regulation mechanism that controls their optimal number of [...] Read more.

Legumes associate with Gram-negative soil bacteria called rhizobia, resulting in the formation of a nitrogen-fixing organ, the nodule. Nodules are an important sink for photosynthates for legumes, so these plants have developed a systemic regulation mechanism that controls their optimal number of nodules, the so-called autoregulation of nodulation (AON) pathway, to balance energy costs with the benefits of nitrogen fixation. In addition, soil nitrate inhibits nodulation in a dose-dependent manner, through systemic and local mechanisms. The CLE family of peptides and their receptors are key to tightly controlling these inhibitory responses. In the present study, a functional analysis revealed that PvFER1, PvRALF1, and PvRALF6 act as positive regulators of the nodule number in growth medium containing 0 mM of nitrate but as negative regulators in medium with 2 and 5 mM of nitrate. Furthermore, the effect on nodule number was found to be consistent with changes in the expression levels of genes associated with the AON pathway and with the nitrate-mediated regulation of nodulation (NRN). Collectively, these data suggest that PvFER1, PvRALF1, and PvRALF6 regulate the optimal number of nodules as a function of nitrate availability. Full article

(This article belongs to the Special Issue Plant Defense Response to Microbial, Herbivorous, and Environmental Interactions)

► Show Figures

Figure 1

25 pages, 4125 KiB

Open AccessReview

Dialog between Kingdoms: Enemies, Allies and Peptide Phytohormones

by Irina Dodueva, Maria Lebedeva and Lyudmila Lutova

Plants 2021, 10(11), 2243; https://doi.org/10.3390/plants10112243 - 21 Oct 2021

Cited by 9 | Viewed by 4412

Abstract

Various plant hormones can integrate developmental and environmental responses, acting in a complex network, which allows plants to adjust their developmental processes to changing environments. In particular, plant peptide hormones regulate various aspects of plant growth and development as well as the response [...] Read more.

Various plant hormones can integrate developmental and environmental responses, acting in a complex network, which allows plants to adjust their developmental processes to changing environments. In particular, plant peptide hormones regulate various aspects of plant growth and development as well as the response to environmental stress and the interaction of plants with their pathogens and symbionts. Various plant-interacting organisms, e.g., bacterial and fungal pathogens, plant-parasitic nematodes, as well as symbiotic and plant-beneficial bacteria and fungi, are able to manipulate phytohormonal level and/or signaling in the host plant in order to overcome plant immunity and to create the habitat and food source inside the plant body. The most striking example of such phytohormonal mimicry is the ability of certain plant pathogens and symbionts to produce peptide phytohormones of different classes. To date, in the genomes of plant-interacting bacteria, fungi, and nematodes, the genes encoding effectors which mimic seven classes of peptide phytohormones have been found. For some of these effectors, the interaction with plant receptors for peptide hormones and the effect on plant development and defense have been demonstrated. In this review, we focus on the currently described classes of peptide phytohormones found among the representatives of other kingdoms, as well as mechanisms of their action and possible evolutional origin. Full article

(This article belongs to the Special Issue Peptide Hormones: Roles in Plant Development, Nutrient Responses and Plant–Microbe Interactions)

► Show Figures

Graphical abstract

27 pages, 11668 KiB

Open AccessArticle

Molecular Insights into the Role of Cysteine-Rich Peptides in Induced Resistance to Fusarium oxysporum Infection in Tomato Based on Transcriptome Profiling

by Marina P. Slezina, Ekaterina A. Istomina, Tatyana V. Korostyleva, Alexey S. Kovtun, Artem S. Kasianov, Alexey A. Konopkin, Larisa A. Shcherbakova and Tatyana I. Odintsova

Int. J. Mol. Sci. 2021, 22(11), 5741; https://doi.org/10.3390/ijms22115741 - 27 May 2021

Cited by 18 | Viewed by 4462

Abstract

Cysteine-rich peptides (CRPs) play an important role in plant physiology. However, their role in resistance induced by biogenic elicitors remains poorly understood. Using whole-genome transcriptome sequencing and our CRP search algorithm, we analyzed the repertoire of CRPs in tomato Solanum lycopersicum L. in [...] Read more.

Cysteine-rich peptides (CRPs) play an important role in plant physiology. However, their role in resistance induced by biogenic elicitors remains poorly understood. Using whole-genome transcriptome sequencing and our CRP search algorithm, we analyzed the repertoire of CRPs in tomato Solanum lycopersicum L. in response to Fusarium oxysporum infection and elicitors from F. sambucinum. We revealed 106 putative CRP transcripts belonging to different families of antimicrobial peptides (AMPs), signaling peptides (RALFs), and peptides with non-defense functions (Major pollen allergen of Olea europaea (Ole e 1 and 6), Maternally Expressed Gene (MEG), Epidermal Patterning Factor (EPF)), as well as pathogenesis-related proteins of families 1 and 4 (PR-1 and 4). We discovered a novel type of 10-Cys-containing hevein-like AMPs named SlHev1, which was up-regulated both by infection and elicitors. Transcript profiling showed that F. oxysporum infection and F. sambucinum elicitors changed the expression levels of different overlapping sets of CRP genes, suggesting the diversification of functions in CRP families. We showed that non-specific lipid transfer proteins (nsLTPs) and snakins mostly contribute to the response of tomato plants to the infection and the elicitors. The involvement of CRPs with non-defense function in stress reactions was also demonstrated. The results obtained shed light on the mode of action of F. sambucinum elicitors and the role of CRP families in the immune response in tomato. Full article

(This article belongs to the Special Issue Plant Innate Immunity 4.0)

► Show Figures

Figure 1

13 pages, 1147 KiB

Open AccessReview

The Roles of Peptide Hormones and Their Receptors during Plant Root Development

by Yu-Chun Hsiao and Masashi Yamada

Genes 2021, 12(1), 22; https://doi.org/10.3390/genes12010022 - 25 Dec 2020

Cited by 30 | Viewed by 6643

Abstract

Peptide hormones play pivotal roles in many physiological processes through coordinating developmental and environmental cues among different cells. Peptide hormones are recognized by their receptors that convey signals to downstream targets and interact with multiple pathways to fine-tune plant growth. Extensive research has [...] Read more.

Peptide hormones play pivotal roles in many physiological processes through coordinating developmental and environmental cues among different cells. Peptide hormones are recognized by their receptors that convey signals to downstream targets and interact with multiple pathways to fine-tune plant growth. Extensive research has illustrated the mechanisms of peptides in shoots but functional studies of peptides in roots are scarce. Reactive oxygen species (ROS) are known to be involved in stress-related events. However, recent studies have shown that they are also associated with many processes that regulate plant development. Here, we focus on recent advances in understanding the relationships between peptide hormones and their receptors during root growth including outlines of how ROS are integrated with these networks. Full article

(This article belongs to the Special Issue The Role of Peptide and Kinase in the Growth of Plants)

► Show Figures

Figure 1

Search Results (11)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI

Saved Queries

Search Filter Reset All

Years

Feature Papers

Subjects

Journals

Article Types

Countries / Regions

Search Results (11)

Further Information

Guidelines

MDPI Initiatives

Follow MDPI