The Novel Cerato-Platanin-Like Protein FocCP1 from Fusarium oxysporum Triggers an Immune Response in Plants.

Songwei Li,Dewen Qiu,Xiufen Yang,Xinwu Pei,Yijie Dong,Yi Zhang,Qianhua Yuan,Mingwang Shi,Hongmei Zeng,Lin Li

doi:10.3390/ijms20112849

Abstract

Panama disease, or Fusarium wilt, the most serious disease in banana cultivation, is caused by Fusarium oxysporum f. sp. cubense (FOC) and has led to great economic losses worldwide. One effective way to combat this disease is by enhancing host plant resistance. The cerato-platanin protein (CPP) family is a group of small secreted cysteine-rich proteins in filamentous fungi. CPPs as elicitors can trigger the immune system resulting in defense responses in plants. In this study, we characterized a novel cerato-platanin-like protein in the secretome of Fusarium oxysporum f. sp. cubense race 4 (FOC4), named FocCP1. In tobacco, the purified recombinant FocCP1 protein caused accumulation of reactive oxygen species (ROS), formation of necrotic reaction, deposition of callose, expression of defense-related genes, and accumulation of salicylic acid (SA) and jasmonic acid (JA) in tobacco. These results indicated that FocCP1 triggered a hypersensitive response (HR) and systemic acquired resistance (SAR) in tobacco. Furthermore, FocCP1 enhanced resistance tobacco mosaic virus (TMV) disease and Pseudomonas syringae pv. tabaci 6605 (Pst. 6605) infection in tobacco and improved banana seedling resistance to FOC4. All results provide the possibility of further research on immune mechanisms of plant and pathogen interactions, and lay a foundation for a new biological strategy of banana wilt control in the future.

Highlights

The filamentous fungus Fusarium oxysporum f. sp. cubense (FOC) is the causal agent of banana fusarium wilt or Panama disease
All proteins were subjected to Gene Ontology (GO) functional annotation analysis; these proteins covered a wide range of molecular functions (MF), cellular components (CC), and biological processes (BP)
Some proteins potentially secreted as a result of the pathogen–host interaction were identified (Table 1), including cellulase, chitinase, carboxypeptidase, lipase, aminopeptidase, glucanase, and one cerato-platanin-like protein (UniProtKB: X0JM38)

Summary

Introduction

The filamentous fungus Fusarium oxysporum f. sp. cubense (FOC) is the causal agent of banana fusarium wilt or Panama disease. Cubense (FOC) is the causal agent of banana fusarium wilt or Panama disease. Four races (1, 2, 3, and 4) of FOC have been identified based on their pathogenicity to different banana varieties. Race 1 and race 2 infect GrosMichel and Bluggoe banana cultivars, respectively. Race 4, the most serious pathogenic race, attacks Mimosa nana Lour and Musa basjoo Siebold, and causes serious banana wilt [1,2]. Fusarium oxysporum is a worldwide soil-borne pathogen and its chlamydospore survives in host plants or soil for decades. When the environment is suitable, mycelia penetrate the banana root and secrete a gel causing a blockage in vascular vessels, blocking water transportation in the plant, resulting in a reddish-brown discoloration and necrosis of the rhizome and pseudostem, eventually leading to leaf collapse and plant death [1,3]

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Conclusion