scholarly journals Plant Growth-Promoting Rhizobacteria May Reduce Fusiform Rust Infection in Nursery-Grown Loblolly Pine Seedlings

2004 ◽  
Vol 28 (4) ◽  
pp. 185-188 ◽  
Author(s):  
S.A. Enebak ◽  
W.A. Carey
Keyword(s):  
Plant Growth ◽  
Seedling Growth ◽  
Loblolly Pine ◽  
Induced Systemic Resistance ◽  
Plant Growth Promoting Rhizobacteria ◽  
Systemic Resistance ◽  
Fusiform Rust ◽  
Rust Infection ◽  
Plant Growth Promoting ◽  
Growth Promoting

Abstract Fusiform rust caused by Cronartium quercuum f.sp. fusiforme (Hedg. & Hunt ex Cumm.) is the most damaging stem disease of Pinus spp. in the southern United States. Plant-growth-promoting rhizobacteria (PGPR) have induced systemic resistance in many host-pathogen systems. To determine whether rhizobacteria could induce systemic resistance to fusiform rust infection, loblolly pine (Pinus taeda L.) seedlings were evaluated for rust resistance following preemergence seed and post emergence foliar sprays with three bacterial strains. Treated seed was sown in one bare root nursery in Alabama and one in Georgia, and seedlings were examined for size differences and rust galls at the end of one season. Treatment with bacteria at the time of sowing did not affect rust galls or seedling growth at the Alabama nursery but reduced galls and increased seedling growth at the Georgia nursery. Bacterial treatment T4 resulted in significantly fewer galls and strains T4 and SE34 resulted in larger seedlings compared to nontreated controls. This is the first report of a reduction in fusiform rust by plant growth-promoting rhizobacteria and although nursery × treatment interactions exist, the current findings suggest that induced systemic resistance is possible. South. J. Appl. For. 28(4):185–188.

scholarly journals Evidence for Induced Systemic Protection to Fusiform Rust in Loblolly Pine by Plant Growth-Promoting Rhizobacteria

Plant Disease ◽  
2000 ◽  
Vol 84 (3) ◽  
pp. 306-308 ◽  
Author(s):  
S. A. Enebak ◽  
W. A. Carey
Keyword(s):  
Plant Growth ◽  
Loblolly Pine ◽  
Bacillus Pumilus ◽  
Plant Growth Promoting Rhizobacteria ◽  
Systemic Resistance ◽  
Bacterial Strains ◽  
Fusiform Rust ◽  
Plant Growth Promoting ◽  
Growth Promoting ◽  
Combined Data

Trials conducted in 1997 and 1998 tested eight strains of plant growth-promoting rhizobacteria (PGPR) for their capacity to induce systemic protection in loblolly pine to the causal agent of fusiform rust. Pine seeds were treated with bacteria at time of sowing, and seedlings were artificially inoculated with basidiospores of Cronartium quercuum f. sp. fusiforme 1 month later. Six months after basidiospore inoculation, seedlings were evaluated for the fusoid swelling or galls characteristic of rust infection. Compared with seedlings from seed not treated with bacteria, two bacterial isolates, Bacillus pumilus (SE34) and Serratia marcescens (90–166), significantly (P = 0.05) reduced the number of galls in 1997 and 1998. Combined data from 1997 and 1998 resulted in two additional isolates, B. pumilus (INR7) and B. pumilus (SE52), significantly (P = 0.05) reducing the number of galls. Averaged over both years, 31% of control seedlings were infected with fusiform rust, while those seedlings treated with bacterial strains SE34, 90–166, INR7, and SE52 had 13, 14, 15, and 16% infection, respectively. These four PGPR strains appear to have induced systemic resistance to fusiform rust in loblolly pine, resulting in less infection over nontreated control seedlings.

scholarly journals Induced systemic resistance impacts the phyllosphere microbiome through plant-microbe-microbe interactions

2021 ◽  
Author(s):  
Anna Sommer ◽  
Marion Wenig ◽  
Claudia Knappe ◽  
Susanne Kublik ◽  
Baerbel Foesel ◽  
...  
Keyword(s):  
Plant Growth ◽  
Induced Systemic Resistance ◽  
Bacterial Species ◽  
Plant Growth Promoting Rhizobacteria ◽  
Systemic Resistance ◽  
Bacillus Thuringiensis Israelensis ◽  
Plant Growth Promoting ◽  
Microbe Interactions ◽  
Growth Promoting ◽  
Dramatic Shift

Both above- and below-ground parts of plants are constantly confronted with microbes, which are main drivers for the development of plant-microbe interactions. Plant growth-promoting rhizobacteria enhance the immunity of above-ground tissues, which is known as induced systemic resistance (ISR). We show here that ISR also influences the leaf microbiome. We compared ISR triggered by the model strain Pseudomonas simiae WCS417r (WCS417) to that triggered by Bacillus thuringiensis israelensis (Bti) in Arabidopsis thaliana. In contrast to earlier findings, immunity elicited by both strains depended on salicylic acid. Both strains further relied on MYC2 for signal transduction in the plant, while WCS417-elicited ISR additionally depended on SAR-associated metabolites, including pipecolic acid. A metabarcoding approach applied to the leaf microbiome revealed a significant ISR-associated enrichment of amplicon sequence variants with predicted plant growth-promoting properties. WCS417 caused a particularly dramatic shift in the leaf microbiota with more than 50% of amplicon reads representing two bacterial species: WCS417 and Flavobacterium sp.. Co-inoculation experiments using WCS417 and At-LSPHERE Flavobacterium sp. Leaf82, suggest that the proliferation of these bacteria is influenced by both microbial and plant-derived factors. Together, our data connect systemic immunity with leaf microbiome dynamics and highlight the importance of plant-microbe-microbe interactions for plant health.

Sign in / Sign up

Export Citation Format

Share Document