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

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

JOURNAL=Frontiers in Microbiology

VOLUME=12

YEAR=2021

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2021.634772

DOI=10.3389/fmicb.2021.634772

ISSN=1664-302X

ABSTRACT=<p>Gummy stem blight and wilt are known to cause enormous losses to the global production of muskmelon (<italic>Cucumis melo</italic>). In this study, the potential of endophytic fungi isolated from leaves of Siam weed (<italic>Chromolaena odorata</italic>) was investigated for the inhibition of mycelial growth of <italic>Stagonosporopsis cucurbitacearum</italic> and <italic>Fusarium equiseti</italic>. 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 <italic>F. equiseti</italic> and <italic>S. cucurbitacearum</italic> 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 <italic>Trichoderma phayaoense</italic>. Pathogenicity test confirmed that <italic>F. equiseti</italic> and <italic>S. cucurbitacearum</italic> were the cause of gummy stem blight and wilt disease in muskmelon seedlings, respectively. However, no disease symptoms were observed in seedlings inoculated with <italic>T. phayaoense</italic>. It was found that <italic>T. phayaoense</italic> could be used preventively in muskmelon seedlings that were inoculated with <italic>F. equiseti</italic> and <italic>S. cucurbitacearum</italic>, which could then reduce the impact on the disease severity index. <italic>T. phayaoense</italic> was also effective in improving plant development by increasing plant height, as well as shoot and root dry weight values. Moreover, <italic>T. phayaoense</italic> could effectively increase weight, diameter, and the circumference and total soluble solid of fruit without having a negative effect on fruit quality parameters. Additionally, <italic>T. phayaoense</italic> was able to tolerate a commonly applied fungicide (metalaxyl) in recommended dosages for field applications.</p>