Isoforms of cysteine peptidases and osmotins instead of chitinases and peptidase inhibitors drive antifungal activity but occur as distinct isoforms in latex and callus tissues of Calotropis procera.
5 affiliations
- 1Departamento de Bioquímica E Biologia Molecular, Centro de Ciências, Universidade Federal Do Ceará, Bloco 907, Campus Do Pici, Fortaleza, Ceará, CEP 60440-554, Brazil. [email protected].
- 2Departamento de Bioquímica E Biologia Molecular, Centro de Ciências, Universidade Federal Do Ceará, Bloco 907, Campus Do Pici, Fortaleza, Ceará, CEP 60440-554, Brazil.
- 3Department of Biology, Federal University of Ceará, Fortaleza, Ceará, CEP 60440-554, Brazil.
- 4Laboratory of Plant Physiology and Biochemistry, National Institute for Amazonian Research - INPA, Manaus, Amazonas, CEP 69011-970, Brazil.
- 5Departamento de Bioquímica E Biologia Molecular, Centro de Ciências, Universidade Federal Do Ceará, Bloco 907, Campus Do Pici, Fortaleza, Ceará, CEP 60440-554, Brazil. [email protected].
Abstract
Main conclusion
Peptidases and osmotins are the primary determinants of antifungal activity, and their expression is tightly linked to tissue specialization in Calotropis procera plants. This study investigated whether callus cultures of two Apocynaceae species, Calotropis procera and Cryptostegia grandiflora, reproduce the antifungal defense system typically found in their latex. Protein fractions obtained from latex and callus tissues were evaluated for antifungal activity against Fusarium solani, F. oxysporum, Colletotrichum lindemuthianum, and C. gloeosporioides, as well as the presence of pathogenesis-related (PR) proteins was investigated. Callus proteins from C. procera (CPCp) exhibited antifungal activity, inhibiting both mycelial growth and spore germination of all tested fungi. In contrast, callus proteins from C. grandiflora (CPCg) showed no detectable antifungal activity. Mechanistic assays demonstrated that CPCp induced plasma membrane permeabilization and the accumulation of reactive oxygen species in fungal spores. Biochemical analyses further revealed that antifungal activity was associated with the presence of peptidases and osmotins but not of peptidase inhibitors and chitinases. Immunological recognition and gene expression analyses indicated that the peptidases and osmotins expressed in callus tissues differ from those present in the latex of C. procera, suggesting the occurrence of distinct protein isoforms. Collectively, these findings demonstrate that peptidases and osmotins are key determinants of antifungal activity in latex plants and reveal that their expression is closely linked to tissue specialization, highlighting the differential regulation of defense protein isoforms between latex and other plant tissues.
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BibTeX
@article{ramos2026isoforms,
title = {{Isoforms of cysteine peptidases and osmotins instead of chitinases and peptidase inhibitors drive antifungal activity but occur as distinct isoforms in latex and callus tissues of Calotropis procera.}},
author = {Márcio V Ramos and Rayanne F Silva and Cristina P S Carvalho and Arlete A Soares and José Francisco C Gonçalves and Patrícia M S Carvalho and Pedro A V R Júnior and João M Matos-Neto and Cleverson D T Freitas},
journal = {Planta},
year = {2026},
month = oct,
doi = {10.1007/s00425-026-05198-2},
url = {https://europepmc.org/article/MED/42859264},
note = {CC BY},
}
RIS
TY - JOUR
TI - Isoforms of cysteine peptidases and osmotins instead of chitinases and peptidase inhibitors drive antifungal activity but occur as distinct isoforms in latex and callus tissues of Calotropis procera.
AU - Márcio V Ramos
AU - Rayanne F Silva
AU - Cristina P S Carvalho
AU - Arlete A Soares
AU - José Francisco C Gonçalves
AU - Patrícia M S Carvalho
AU - Pedro A V R Júnior
AU - João M Matos-Neto
AU - Cleverson D T Freitas
PY - 2026
DA - 2026/10/11
JO - Planta
DO - 10.1007/s00425-026-05198-2
UR - https://europepmc.org/article/MED/42859264
AB - Main conclusion Peptidases and osmotins are the primary determinants of antifungal activity, and their expression is tightly linked to tissue specialization in Calotropis procera plants. This study investigated whether callus cultures of two Apocynaceae species, Calotropis procera and Cryptostegia grandiflora, reproduce the antifungal defense system typically found in their latex. Protein fractions obtained from latex and callus tissues were evaluated for antifungal activity against Fusarium solani, F. oxysporum, Colletotrichum lindemuthianum, and C. gloeosporioides, as well as the presence of pathogenesis-related (PR) proteins was investigated. Callus proteins from C. procera (CPCp) exhibited antifungal activity, inhibiting both mycelial growth and spore germination of all tested fungi. In contrast, callus proteins from C. grandiflora (CPCg) showed no detectable antifungal activity. Mechanistic assays demonstrated that CPCp induced plasma membrane permeabilization and the accumulation of reactive oxygen species in fungal spores. Biochemical analyses further revealed that antifungal activity was associated with the presence of peptidases and osmotins but not of peptidase inhibitors and chitinases. Immunological recognition and gene expression analyses indicated that the peptidases and osmotins expressed in callus tissues differ from those present in the latex of C. procera, suggesting the occurrence of distinct protein isoforms. Collectively, these findings demonstrate that peptidases and osmotins are key determinants of antifungal activity in latex plants and reveal that their expression is closely linked to tissue specialization, highlighting the differential regulation of defense protein isoforms between latex and other plant tissues.
SN - 0032-0935
SN - 1432-2048
ER -