Tobacco growth enhancement and blue mold disease protection by rhizobacteria: relationship between plant growth promotion and systemic disease protection by PGPR strain 90-166

• Published in: Plant and soil Vol. 262; no. 1-2; pp. 277 - 288
• Main Authors: Zhang, S, Reddy, M.S, Kloepper, J.W
• Format: Journal Article
• Language: English
• Published: Dordrecht Kluwer Academic Publishers 01.05.2004; Springer; Springer Nature B.V
• Subjects: Biological and medical sciences; Biological control; biological control agents; Control; disease resistance; disease severity; Fundamental and applied biological sciences. Psychology; fungal diseases of plants; Fungal plant pathogens; Fungi; Growth promotion; Hospital beds; Mold; molds (fungi); Nicotiana tabacum; Pathogens; Peronospora; Peronospora tabacina; Phytopathology. Animal pests. Plant and forest protection; Plant diseases; Plant growth; Plant growth promoting rhizobacteria; plant pathogenic fungi; Plant roots; Plants; Regression analysis; Seed treatment; Seed treatments; systemic acquired resistance; Tobacco; Plant pathology; Plant pathogen; Mycosis; Peronospora tabacina; Growth; Biological control; Phycomycetes; Stimulant plant; Systemic; Nicotiana tabacum; Induced resistance; plant growth-promoting rhizobacteria; Fungi; Microbiological control; Dicotyledones; Bacterial inoculation; Angiospermae; Serratia marcescens; Bacteria; Plant growth promoting rhizobacteria; Solanaceae; Enterobacteriaceae; Thallophyta; systemic acquired resistance; Mycology; Enhancement factor; Experimental study; Bacteriology; Strain; Infection; Soil biology; induced systemic resistance; Spermatophyta; Soil plant relation
• DOI: 10.1023/b:plso.0000037048.26437.fa
• ISSN: 0032-079X

The effect of plant growth-promoting rhizobacteria (PGPR) on plant growth and systemic protection against blue mold disease of tobacco (Nicotiana tabacum L.), caused by Peronospora tabacina, was investigated in the greenhouse. Five PGPR strains with known plant growth promotion and induced resistance activities in other crops were used in these studies. PGPR strains were applied as seed treatments alone at planting and in combination with root drenches after planting. When PGPR were applied as seed treatments, PGPR strains 90-166, SE34 and C-9 at 109 CFU mL-1 increased all or most parameters of plant growth 7 weeks after planting (WAP), while 89B-61 and T4 did not enhance any or few parameters. Seed treatments with PGPR strains 90-166 and C-9 at 109 CFU mL-1 at 13 WAP resulted in significant disease reduction in blue mold severity compared to the nontreated control. When PGPR were applied as seed treatments and root drenches, all PGPR strains at 109 CFU mL-1 enhanced tobacco growth compared to the nontreated control at 7 WAP. The time interval between the last PGPR treatment and challenge with P. tabacina affected systemic disease protection elicited by some PGPR strains. When the time interval was 8 weeks, 3 PGPR strains 90-166, SE34 and T4 at 109 CFU mL-1 reduced disease severity, while treatments with all tested PGPR strains resulted in significantly lower disease compared to the nontreated control when it was reduced to 6 weeks. Regression analysis demonstrated a significant relationship between plant growth promotion and systemic protection against blue mold elicited by PGPR strain 90-166. Tobacco growth promotion (X) was calculated by percentage of increase in total fresh plant weight relative to the nontreated control. Systemic protection (Y) against blue mold disease was represented by percentage of decrease in disease severity over the nontreated control. This relationship was best described by the model Y=-4.48+0.37 X (r 2=0.86, P=0.0001) when strain 90-166 was applied as seed treatments. In the experiment in which strain 90-166 was applied as seed treatments and root drenches, Y=6.60+0.14 X (r 2=0.88, P<0.0001) defined this relationship when the time interval was 8 weeks. When the time interval was reduced to 6 weeks, Y=12.30+0.28 X (r 2=0.80, P=0.0005) defined the relationship.