Bacillus licheniformis PR2 Controls Fungal Diseases and Increases Production of Jujube Fruit under Field Conditions

Jun-Hyeok Kwon,Chaw Ei Htwe Maung,Young Sang Ahn,Jae-Hyun Moon,Uk Lee,Yun-Serk Park,Sang-Jae Won,Henry B Ajuna

doi:10.3390/horticulturae7030049

Jun-Hyeok Kwon, Chaw Ei Htwe Maung + Show 6 more

Open Access

https://doi.org/10.3390/horticulturae7030049

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Journal: Horticulturae	Publication Date: Mar 12, 2021
Citations: 18	License type: CC BY 4.0

Affiliation: Chonnam National University, Korea Forest Service

Abstract

There is a growing interest in using biocontrol agents to control fungal diseases and increase the production of jujube fruit (Zizyphus jujua Miller var. inermis Rehder). The purpose of this study was to use Bacillus licheniformis PR2 to inhibit fungal diseases and promote fruit production in jujube orchards. B. licheniformis PR2 secreted 92.4 unit/mL of chitinase, which inhibited fungal phytopathogens through hyphal alterations with swelling and bulbous structures. B. licheniformis PR2 also inhibited mycelial growths of fruit fungal pathogens Botrytis cinerea, Colletotrichum gloeosporioides, and Phytophthora nicotianae by 81.3%, 60.1%, and 67.0%, respectively. B. licheniformis PR2 increased jujube fruit yield by 17.9 kg/tree by reducing rotting damage caused by fungal pathogens, with a yield 3.2 times higher than that achieved by the control without PR2 treatment. In addition, B. licheniformis PR2 produced auxin, which promoted cell division after flower fertilization, thus increasing fruit length and diameter by 1.2-fold compared to those of the control. These results confirmed that eco-friendly B. licheniformis PR2 could effectively control fungal diseases in jujube orchards and improve its fruit size and yield.

Highlights

The fruit of the jujube (Zizyphus jujua Miller var. inermis Rehder) is known to contain several components such as phenolic compounds, minerals, polysaccharides, vitamin complexes, and dietary fiber with high nutritional or health-promoting values [1,2,3].Several of these substances are biologically active compounds known to have positive effects on human health, such as antioxidative and immunoregulatory activities and heart disease preventing effects [1,3]
The objective of this study was to investigate the effects of using Bacillus licheniformis PR2 as a candidate biocontrol agent to prevent fruit fungal diseases, diseases caused by B. cinerea, C. gloeosporioides, and P. nicotianae, increasing the production of jujube fruits
B. licheniformis PR2 used in this study secreted 92.4 unit/mL

Summary

Introduction

Inermis Rehder) is known to contain several components such as phenolic compounds, minerals, polysaccharides, vitamin complexes, and dietary fiber with high nutritional or health-promoting values [1,2,3]. Several of these substances are biologically active compounds known to have positive effects on human health, such as antioxidative and immunoregulatory activities and heart disease preventing effects [1,3]. Most fungal diseases are difficult to eradicate and disease outbreaks can continue to occur across several growing seasons.

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