Abstract
To avoid the unreasonable use of chemical fertilizer, an environmentally friendly means of improving soil fertility is required. This study explored the role of the plant growth-promoting rhizosphere bacteria (PGPR) strain Bacillus velezensis SAAS-63 in improving nutrient stress in lettuce. Compared with no inoculation, B. velezensis SAAS-63 inoculants exhibited significantly increased fresh weight, root length, and shoot height under nutrient deficiency, as well as improved antioxidant activities and proline contents. The exogenous addition of B. velezensis SAAS-63 also significantly increased the accumulation of macroelements and micronutrients in lettuce. To elucidate the resistance mechanisms induced by B. velezensis SAAS-63 under nutrient stress, high-throughput sequencing and multi-omics analysis were performed. Inoculation with B. velezensis SAAS-63 altered the microbial community of the rhizosphere and increased the relative abundances of Streptomyces, Actinoallomurus, Verrucomicrobia, and Chloroflexi. It is worth noting that the inoculant SAAS-63 can affect plant rhizosphere metabolism. The inoculant changed the metabolic flow of phenylpropanoid metabolic pathway under nutrient deficiency and promoted phenylalanine to participate more in the synthesis of lignin precursors and coumarin substances by inhibiting the synthesis of flavone and isoflavone, thus improving plant resistance. This study showed that the addition of inoculant SAAS-63 could help plants recruit microorganisms to decompose and utilize trehalose and re-established the carbon metabolism of the plant rhizosphere. Additionally, microbes were found to be closely related to the accumulation of metabolites based on correlation analysis. The results indicated that the addition of PGPRs has an important role in regulating soil rhizosphere microbes and metabolism, providing valuable information for understanding how PGPRs affect complex biological processes and enhance plant adaptation to nutrient deficiency. KEY POINTS: • Inoculation with SAAS-63 significantly promoted plant growth under nutrient-deficient conditions • Inoculation with SAAS-63 affected rhizosphere microbial diversity and community structure • Inoculation with SAAS-63 affected plant rhizosphere metabolism and induced plants to synthesize substances that resist stress.
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Claims 9
Claim · model-written summary
Under nutrient deficiency, SAAS-63 inoculation significantly increased fresh weight, root length and shoot height of lettuce compared with no inoculation.
- Taxon
- lettuce
Lactuca sativat1 - Treatment
- B. velezensis SAAS-63 inoculantse1
- Interactor
- Bacillus velezensis SAAS-63
Bacillus velezensist1symbiont - Outcome
- fresh weight, root length, and shoot heighte1
- Direction
- increasede1
- Comparator
- no inoculatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e1“Compared with no inoculation, B. velezensis SAAS-63 inoculants exhibited significantly increased fresh weight, root length, and shoot height under nutrient deficiency, as well as improved antioxidant activities and proline contents”
Claim · model-written summary
Under nutrient deficiency, SAAS-63 inoculation improved antioxidant activities and proline contents of lettuce compared with no inoculation.
- Taxon
- lettuceLactuca sativat1
- Treatment
- B. velezensis SAAS-63 inoculantse1
- Interactor
- Bacillus velezensis SAAS-63Bacillus velezensist1symbiont
- Outcome
- antioxidant activities and proline contentse1
- Direction
- improvede1
- Comparator
- no inoculatione1
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e1“Compared with no inoculation, B. velezensis SAAS-63 inoculants exhibited significantly increased fresh weight, root length, and shoot height under nutrient deficiency, as well as improved antioxidant activities and proline contents”
Claim · model-written summary
Exogenous SAAS-63 significantly increased the accumulation of macroelements and micronutrients in lettuce.
- Taxon
- lettuceLactuca sativat1
- Treatment
- exogenous addition of B. velezensis SAAS-63e2
- Interactor
- Bacillus velezensis SAAS-63Bacillus velezensist1symbiont
- Outcome
- accumulation of macroelements and micronutrientse2
- Direction
- increasede2
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e2“The exogenous addition of B. velezensis SAAS-63 also significantly increased the accumulation of macroelements and micronutrients in lettuce”
Claim · model-written summary
SAAS-63 inoculation increased the relative abundances of Streptomyces, Actinoallomurus and Verrucomicrobia in the lettuce rhizosphere.
- Taxon
- lettuceLactuca sativat1
- Treatment
- Inoculation with B. velezensis SAAS-63e3
- Interactor
- Streptomyces, Actinoallomurus, Verrucomicrobia
StreptomycesVerrucomicrobiotaActinoallomuruse3symbiont - Outcome
- relative abundances of Streptomyces, Actinoallomurus, Verrucomicrobiae3
- Direction
- increasede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e3“Inoculation with B. velezensis SAAS-63 altered the microbial community of the rhizosphere and increased the relative abundances of Streptomyces, Actinoallomurus, Verrucomicrobia, and Chloroflexi”
Claim · model-written summary
SAAS-63 inoculation increased the relative abundance of Chloroflexi in the lettuce rhizosphere.
- Taxon
- lettuceLactuca sativat1
- Treatment
- Inoculation with B. velezensis SAAS-63e3
- Interactor
- ChloroflexiChloroflexotae3symbiont
- Outcome
- Chloroflexie3
- Direction
- increasede3
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e3“Inoculation with B. velezensis SAAS-63 altered the microbial community of the rhizosphere and increased the relative abundances of Streptomyces, Actinoallomurus, Verrucomicrobia, and Chloroflexi”
Claim · model-written summary
The inoculant promoted phenylalanine use in the synthesis of lignin precursors and coumarin substances under nutrient deficiency.
- Taxon
- lettuceLactuca sativat1
- Treatment
- The inoculante4
- Compound
- phenylalaninee4
- Outcome
- synthesis of lignin precursors and coumarin substancese4
- Direction
- promotede4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e4“The inoculant changed the metabolic flow of phenylpropanoid metabolic pathway under nutrient deficiency and promoted phenylalanine to participate more in the synthesis of lignin precursors and coumarin substances by inhibiting the synthesis of flavone and isoflavone”
Claim · model-written summary
The inoculant inhibited the synthesis of flavone and isoflavone in lettuce under nutrient deficiency.
- Taxon
- lettuceLactuca sativat1
- Treatment
- The inoculante4
- Outcome
- synthesis of flavone and isoflavonee4
- Direction
- inhibitinge4
Not reportedComparator
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e4“The inoculant changed the metabolic flow of phenylpropanoid metabolic pathway under nutrient deficiency and promoted phenylalanine to participate more in the synthesis of lignin precursors and coumarin substances by inhibiting the synthesis of flavone and isoflavone”
Claim · model-written summary
SAAS-63 may help lettuce plants recruit microbes that use trehalose, re-establishing rhizosphere carbon metabolism.
- Taxon
- lettuceLactuca sativat1
- Treatment
- inoculant SAAS-63e6
- Compound
- trehalosee6
- Outcome
- carbon metabolism of the plant rhizospheree6
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e6“the addition of inoculant SAAS-63 could help plants recruit microorganisms to decompose and utilize trehalose and re-established the carbon metabolism of the plant rhizosphere”
Claim · model-written summary
Microbes were closely related to the accumulation of metabolites by correlation analysis.
- Taxon
- lettuceLactuca sativat1
- Interactor
- microbese5symbiont
- Outcome
- accumulation of metabolitese5
Not reportedDirection
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
t1“the effect of Bacillus velezensis SAAS-63 on resisting nutrient stress in lettuce”
e5“microbes were found to be closely related to the accumulation of metabolites based on correlation analysis”
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Claims are grouped by organism, treatment and what was measured or targeted. A paper counts as positive when any of its claims in the group is positive.