Inoculation and colonization of isolated entomopathogenic fungi Beauveria bassiana in rice plants, Oryza sativa L. through seed immersion method

Etr H. K. Khashaba

doi:10.1186/s41938-021-00434-1

Abstract

BackgroundThe aims of the present study were to isolate and identify native entomopathogenic fungi, Beauveria bassiana from the Egyptian soil and to evaluate the artificial establishment of B. bassiana as endophytes in rice plants through seeds immersion.ResultsTen soil samples were collected from different cultivated fields at the Ismailia Governorate. Only one sample was positive with a ratio of 10%. Sequencing of the internal transcribed spacer (ITS) region indicated that the isolate obtained from the soil sample belongs to B. bassiana and was registered under the accession no. MN337282. To test the endophytic colonization of B. bassiana, rice seeds were soaked by B. bassiana with a concentration of 5 × 107 spores/ml, to test when B. bassiana become an endophyte in rice plants. The plants were examined for endophytic presence of B. bassiana, 30 days post treatment. PCR amplification using fungal specific primers for a conserved region of β-tubulin gene yielded identical 360 bp products from both B. bassiana and rice treated plants.ConclusionThe results showed that seeds immersion with a conidial suspension proved to be a good method to introduce B. bassiana into rice leaves to protect the rice plants against stem borers.

Highlights

The aims of the present study were to isolate and identify native entomopathogenic fungi, Beauveria bassiana from the Egyptian soil and to evaluate the artificial establishment of B. bassiana as endophytes in rice plants through seeds immersion
Out of 10 soil samples collected from different regions at Ismailia Governorate, only one sample was positive to EPN from a field cultivated with tomato with a ratio of 10%
The usage of seed immersion technique successfully introduced the B. bassiana isolate into rice plants with a ratio ~ 70% of the treated plants after 30 days of greenhouse trial

Summary

Introduction

The aims of the present study were to isolate and identify native entomopathogenic fungi, Beauveria bassiana from the Egyptian soil and to evaluate the artificial establishment of B. bassiana as endophytes in rice plants through seeds immersion. Microbial control of insect pests reduces the reliance on chemical pesticides and increases sustainability of agriculture (Singh et al 2015). Entomopathogenic fungi (EPF) are an important biological control agent. Beauveria bassiana is a facultative universal entomopathogen with an extremely broad host range. It was first discovered by Agostino Bassi de Lodi in larval of silkworms (Keswani et al 2013). B. bassiana is considered as the most desired endophytic fungal entomopathogen to date. Endophytes are known to affect the interactions of plants with their

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