Bioactivity and Control Efficacy of the Novel Antibiotic Tetramycin against Various Kiwifruit Diseases.

Qiuping Wang,Youhua Long,Yue Su,Cheng Zhang,Qiang Ai,Xiaomao Wu,Yang Lei

doi:10.3390/antibiotics10030289

Abstract

Tetramycin, a novel polyene agriculture antibiotic, has excellent antimicrobial activity against many plant pathogens. In this study, the antimicrobial activities of tetramycin and conventional antibiotics on eight common pathogens and their field control efficacies against four serious diseases in kiwifruit were investigated. The results show that 0.3% tetramycin aqueous solutions (AS) exhibited the superior antibacterial and antifungal activity against Pseudomonas syringae pv. actinidiae, Pseudomonas fulva, Agrobacterium tumefaciens, Botryosphaeria dothidea, Phomopsis sp., Alternaria tenuissima, Armillariella mellea and Phytophthora cactorum of kiwifruit pathogens with EC50 values of 1.21, 1.24, 0.72, 0.14, 0.09, 0.16, 0.06 and 0.17 mg kg−1, respectively. These EC50 values of tetramycin were much higher than those of conventional kasugamycin, zhongshengmycin or polyoxin. Meanwhile, 0.3% tetramycin AS possessed the good field control efficacies for canker, soft rot, blossom blight and brown spot disease of kiwifruit with 74.45, 83.55, 84.74 and 89.62%. Moreover, 0.3% tetramycin AS application notably increased fruit resistance substances contents, activated fruit superoxide dismutase and polyphenoloxidase activities, as well as remarkably enhanced fruit growth, improved fruit quality and storability. This study highlights that tetramycin can be used as a preferred alternative to conventional antibiotics in kiwifruit production.

Highlights

Kiwifruit (Actinidia), an emerging, healthy and economical fruit, has been commercially cultivated worldwide on a large scale since the 1970s
The toxicities of tetramycin, polyoxin, kasugamycin or zhongshengmycin against eight pathogens of kiwifruit are shown in Table 1. 0.3% Tetramycin aqueous solutions (AS) exhibited a superior toxicity potential for Psa, P. fulva and A. tumefaciens of bacterial pathogens in kiwifruit with EC50 values of 1.21, 1.24 and 0.72 mg kg−1, which were 101.91, 99.12 and 721.17 folds, or 14.01, 209.06 and 3905.39 folds higher than 4.0% kasugamycin wettable powder (WP) or 3.0% zhongshengmycin
WP, respectively. 0.3% tetramycin AS caused the greatest toxicities of mycelium growth for B. dothidea and Phomopsis sp. of kiwifruit soft rot with EC50 values of 0.14 and 0.09 mg kg−1, which were 603.36 and 438.67 folds, or 5158.64 and 14515.11 folds higher than 5.0%

Summary

Introduction

Kiwifruit (Actinidia), an emerging, healthy and economical fruit, has been commercially cultivated worldwide on a large scale since the 1970s. As commercial cultivation of kiwifruit expanded, many diseases gradually appeared in kiwifruit orchards and have become increasingly prominent and serious problems [3]. These serious diseases include bacterial canker, soft rot, bacterial blossom blight, brown spot and root rot, etc. Phoma exigua, is a major disease of postharvest kiwifruit [7,8,9,10,11,12] The occurrence of these diseases seriously affects the quality and yield of kiwifruit, as well as being a frequent cause of major economic losses worldwide

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Discussion

Conclusion