Evaluation of a Newly Identified Endophytic Fungus, Trichoderma phayaoense for Plant Growth Promotion and Biological Control of Gummy Stem Blight and Wilt of Muskmelon.

Wipornpan Nuangmek,Saisamorn Lumyong,Nakarin Suwannarach,Worawoot Aiduang,Jaturong Kumla

doi:10.3389/fmicb.2021.634772

Abstract

Gummy stem blight and wilt are known to cause enormous losses to the global production of muskmelon (Cucumis melo). In this study, the potential of endophytic fungi isolated from leaves of Siam weed (Chromolaena odorata) was investigated for the inhibition of mycelial growth of Stagonosporopsis cucurbitacearum and Fusarium equiseti. Twenty-one fungal isolates were obtained. The results indicated that a fungal isolate UP-L1I3 displayed the highest percentage in terms of inhibition of the mycelial growth of F. equiseti and S. cucurbitacearum at 90.80 and 81.60%, respectively. Consequently, this isolate was selected for its potential ability to promote plant growth and control gummy stem blight and wilt in muskmelon seedlings. Morphological and multilocus phylogenetic analyses revealed that the isolate UP-L1I3 was a new species that has been described herein as Trichoderma phayaoense. Pathogenicity test confirmed that F. equiseti and S. cucurbitacearum were the cause of gummy stem blight and wilt disease in muskmelon seedlings, respectively. However, no disease symptoms were observed in seedlings inoculated with T. phayaoense. It was found that T. phayaoense could be used preventively in muskmelon seedlings that were inoculated with F. equiseti and S. cucurbitacearum, which could then reduce the impact on the disease severity index. T. phayaoense was also effective in improving plant development by increasing plant height, as well as shoot and root dry weight values. Moreover, T. phayaoense could effectively increase weight, diameter, and the circumference and total soluble solid of fruit without having a negative effect on fruit quality parameters. Additionally, T. phayaoense was able to tolerate a commonly applied fungicide (metalaxyl) in recommended dosages for field applications.

Highlights

Muskmelon (Cucumis melo L.) is one of the most popular edible fruits in the world
Gummy stem blight disease caused by Stagonosporopsis cucurbitacearum, and wilt caused by Fusarium oxysporum f. sp. melonis, are important diseases associated with muskmelons and have been known to cause significant losses in yield and quality of this fruit (Gomez and Tello, 2000; Perchepied and Pitrat, 2004; Li et al, 2015; Garampalli et al, 2016)
The results showed that the fungal isolate UP-L1I3 showed the highest degree of percentage for the inhibition of mycelial growth of F. equiseti Sustainable Development of Biological Resources (SDBR)-UP-PA002 and S. cucurbitacearum SDBR-CMU292 at 90.80 and 81.60%, respectively, by dual culture assay (Table 1; Figure 1)

Summary

Introduction

Muskmelon (Cucumis melo L.) is one of the most popular edible fruits in the world. Plant pathogenic microorganisms (bacteria, fungi, and viruses) are known to cause diseases in muskmelons under the field before they are harvested, during harvesting and during storage, all of which can cause considerable yield loses (Walcott et al, 2004; Malik et al, 2010; Kehinde, 2013). Fungi in the genera Alternaria, Colletotrichum, Cladosporium, Fusarium, Penicillium, Phytophthora, and Stagonosporopsis have been reported to cause a range of leaf, fruit, stem, and/or root diseases in muskmelons (Li et al, 2015; Garampalli et al, 2016; Ghuffar et al, 2018). Many researchers have been interested in application of beneficial microorganisms, especially biological control agents in replacing chemical fungicides that can support the sustainability of the agriculture, produce safe food, and reduce environmental pollution (Cal et al, 2009; Wackett, 2013; Gava and Pinto, 2016)

Methods

Results

Discussion

Conclusion