Article Figures & Data
Tables
- Table 1.
Experiments carried out to investigate differences in environmental fitness between different SBW25 variants in soil and in the rhizospheres of pea and wheat
Expt SBW25 strain Novel gene(s) Insertion site Environment Comparison between wild type and triply marked recombinant Wild type None Wheat phylloplane SBW25EeZY-6KX lacZY Ee Wheat phylloplane SBW25EeZY-6KX aph-1 xylE -6- Wheat phylloplane Effect of insertion site, tested in competition with SBW25EeZY-6KX SBW25EeK aph-1 Ee Rhizosphere of wheat SBW25-6K aph-1 -6- Rhizosphere of wheat Effect of metabolic load SBW25-6K aph-1 -6- Rhizospheres of wheat and pea SBW25-6KX aph-1 xylE -6- Rhizospheres of wheat and pea SBW25EeZY-6KX aph-1 xylE -6- Rhizospheres of wheat and pea SBW25EeZY-6KX lacZY Ee Rhizospheres of wheat and pea Effect of environment SBW25-6K aph-1 -6- Rhizospheres of wheat and pea, soil SBW25-6KX aph-1 xylE -6- Rhizospheres of wheat and pea, soil SBW25EeZY-6KX aph-1 xylE -6- Rhizospheres of wheat and pea, soil SBW25EeZY-6KX lacZY Ee Rhizospheres of wheat and pea, soil - Table 2.
Effect of insertion site on environmental fitness ofP. fluorescens SBW25 variants in the rhizosphere of spring wheata
No. of days after planting % and logit %a SBW25-6K SBW25EeK 0 40.7 (0.03) a 52.9 (0.12) ab 7 44.9 (−0.33) a 32.3 (−0.82) a 14 59.1 (0.56) ab 70.5 (0.95) b 21 86.2 (1.71) bc 67.8 (0.80) ab 28 76.5 (1.39) bc 86.6 (3.61) c 35 58.3 (0.09) a 60.9 (0.64) ab ↵a SBW25 variants were applied to spring wheat as a seed coating at the time of planting (n = 5). Data are expressed as the percentage of SBW25-6K or SBW25EeK variants (logit transformed data in parentheses) in a population containing initially equal proportions of SBW25EeZY-6KX variants (lacZY xylE aph-1) and SBW25-6K (aph-1 at the -6- site) or equal proportions of SBW25EeZY-6KX and SBW25EeK (aph-1 at the Ee site). Significant (P < 0.05) differences between two treatments were obtained by LSD analyses and are indicated by different letters. The overall significance for SBW25-6K was <0.01, and that for SBW25EeK was <0.001.
- Table 3.
Effect of metabolic load on the environmental fitness ofP. fluorescens SBW25 variants in the rhizospherea
SBW25 variant % and logit % of total introducedP. fluorescens SBW25 population at indicated time (days) 0 14 28 SBW25-6K 30.0 (−0.87) a 52.4 (0.13) b 55.3 (0.23) b SBW25-6KX 44.8 (−0.21) b 22.5 (−1.02) a 20.0 (−1.61) a SBW25EeZY-6KX 25.3 (−1.10) a 25.1 (−1.26) a 24.8 (−1.14) a ↵a Data were derived from both pea and wheat rhizospheres. SBW25 variants were applied to the seed in similar proportions (SBW25-6K/SBW25-6KX/SBW25EeZY-6KX ratio, 3:4.5:2.5) (n = 8). Data are expressed as a percentage of the total introduced Pseudomonas population and as the logit transformation of the percentage data (in parentheses). Significant (P < 0.05) differences between two treatments were obtained by LSD analyses and are indicated by different letters. The overall significances for values obtained on days 0, 14, and 28 were all <0.01.
- Table 4.
Effect of different environments on the relative survival of P. fluorescens SBW25EeZY-6KX in a mixture of SBW25 variantsa
No. of days after inoculation % and logit % ofP. fluorescens SBW25EeZY-6KX in a mixture of SBW25 variants in: Pea rhizosphere Wheat rhizosphere Soil 0 26.7 (−1.11) 23.7 (−1.21) 24.9 (−1.11) a 14 26.9 (−1.01) 14.3 (−2.02) 5.6 (−2.84) b 28 34.7 (−1.11) 28.8 (−0.75) 1.6 (−4.24) c ↵a The mixtures contained SBW25-6K, SBW25-6KX, and SBW25EeZY-6KX in equal proportions. Variant mixtures were applied either to the seed or as a soil drench (n= 4). Data are expressed as the percentage of SBW25EeZY-6KX in the total population of SBW25 variants and as logit transformation of the percentage data (in parentheses). Significant (P < 0.05) differences between two treatments were obtained by LSD analyses and are indicated by different letters. The overall significance for soil was <0.001; the data for the rhizospheres were not significant.
