Original article
Bacillus strain selection with plant growth-promoting mechanisms as potential elicitors of systemic resistance to gray mold in pepper plants

https://doi.org/10.1016/j.sjbs.2020.06.015Get rights and content
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Highlights

  • Bacillus licheniformis induced resistance against gray mold in pepper plants.

  • Bacillus licheniformis and Bacillus pumilus inhibited the growth of Botrytis cinerea and Fusarium solani.

  • Plant growth promoting mechanisms were confirmed by isolated Bacillus strains.

Abstract

Certain soil bacteria produce beneficial effects on the growth and health of plants; hence, their use is steadily increasing. Five strains of Bacillus with plant growth-promoting potential were selected in this study, which produced indole-3-acetic acid levels below 50 µg.mL−1. On the other hand, while only strains M8 and M15 dissolved phosphorus, the latter was the only strain that did not produce siderophores. Only strains M8 and M16 significantly inhibited the in vitro growth of Botrytis cinerea and Fusarium solani phytopathogens, whose inhibition ranges fluctuated between 60% and 63% for strains M8 and M16 against B. cinerea and between 40% and 53% for strains M8 and M16 against F. solani. Based on these results, the need to implement resistance induction against gray mold on pepper plants was determined using strains M8 and M16. In this case, strain M16 inhibited the propagation of the necrotic spot by approximately 70%, whereas strain M8 significantly reduced the superoxide dismutase activity in systemic leaves, which substantially increased in plants inoculated with strain M8 and infected with the pathogen. Accordingly, the use of native rhizobacteria may entail biotechnological progress for the integrated management of crops in agriculture industry.

Keywords

Bacillus
Botrytis cinerea
Capsicum annuum
Induced systemic resistance
Plant growth-promoting rhizobacteria

Abbreviations

BE
biocontrol efficacy
CAS
chrome azurol sulphonate
DAI
day after infection
IAA
indole-3-acetic acid
HR
hypersensitive response
NBT
nitro blue tetrazolium
PCR
polymerase chain reaction
PGPR
plant growth-promoting rhizobacteria
SOD
superoxide dismutase

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Peer review under responsibility of King Saud University.