Combined Application of Rhizosphere Bacteria with Endophytic Bacteria Suppresses Root Diseases and Increases Productivity of Black Pepper (Piper nigrum L.)

Sy Dinh Nguyen,Anh Dzung Nguyen,Van Anh Ngo,Trung Dzung Tran,Hoang Van Chuyen,Thi Huyen Trang Trinh,Tinh Van Nguyen

doi:10.3390/agriculture11010015

Abstract

Black pepper (Piper nigrum L.) is one of the most important crops and global demand continues to increase, giving it a high export value. However, black pepper cultivation has been seriously affected by a number of pathogenic diseases. Among them, “quick wilt” caused by Phytophthora sp., “slow decline” caused by Fusarium sp., and root-knot nematode Meloidogyne sp. have a serious negative effect on black pepper growth and productivity. There have been different chemical and biological methods applied to control these diseases, but their effectiveness has been limited. The aim of this research was to evaluate different combinations of rhizosphere bacteria and endophytic bacteria isolated from black pepper farms in the Central Highland of Vietnam for their ability to suppress pathogens and promote black pepper growth and yield. Formula 6, containing the strains Bacillus velezensis KN12, Bacillus amyloliquefaciens DL1, Bacillus velezensis DS29, Bacillus subtilis BH15, Bacillus subtilis V1.21 and Bacillus cereus CS30 exhibited the largest effect against Phytophthora and Fusarium in the soil and in the roots of black pepper. These bio-products also increased chlorophyll a and b contents, which led to a 1.5-fold increase of the photosynthetic intensity than the control formula and a 4.5% increase in the peppercorn yield (3.45 vs. 3.30 tons per hectare for the control). Our results suggest that the application of rhizosphere and endophytic bacteria is a promising method for disease control and growth-promotion of black pepper.

Highlights

Black pepper (Piper nigrum L.) is a perennial woody vine in the Piperaceae family which is mainly cultivated in tropical and sub-tropical countries such as India, Indonesia, Malaysia, Brazil, Thailand, Sri Lanka, China, and Vietnam [1]
“quick wilt” disease, which is caused by Phytophthora tropicalis and Phytophthora capsici [5], and “slow decline” disease, which is caused by Fusarium spp., and the root-knot nematode Meloidogyne spp. [6,7], are the most serious diseases that damage the growth and productivity of black pepper crops [8,9]
It was reported that the use of rhizosphere bacteria and endophytic bacteria are effective for disease management and plant growth promotion, and are environmentally friendly for agricultural products including black pepper [3,10,11]

Summary

Introduction

Black pepper (Piper nigrum L.) is a perennial woody vine in the Piperaceae family which is mainly cultivated in tropical and sub-tropical countries such as India, Indonesia, Malaysia, Brazil, Thailand, Sri Lanka, China, and Vietnam [1]. The utilization of chemical fungicides and nematodecides are the most common approaches for disease management of black pepper in Vietnam. This method is harmful to the farmers and the environment due to the potential pollution and lack of biosafety indicators. It was reported that the use of rhizosphere bacteria and endophytic bacteria are effective for disease management and plant growth promotion, and are environmentally friendly for agricultural products including black pepper [3,10,11].

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Conclusion