Comparative conventional and phenomics approaches to assess symbiotic effectiveness of Bradyrhizobia strains in soybean (Glycine max L. Merrill) to drought

• Published in: Scientific reports Vol. 7; no. 1; pp. 6958 - 14
• Main Authors: Govindasamy, Venkadasamy, George, Priya, Aher, Lalitkumar, Ramesh, Shunmugiah V., Thangasamy, Arunachalam, Anandan, Sivalingam, Raina, Susheel Kumar, Kumar, Mahesh, Rane, Jagadish, Annapurna, Kannepalli, Minhas, Paramjit Singh
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 31-07-2017; Nature Publishing Group; Nature Portfolio
• Subjects: 38; 38/22; 38/23; 38/39; 631/326/2522; 631/449/2661/2665; 9/10; Bradyrhizobium; Bradyrhizobium - metabolism; Bradyrhizobium - physiology; Canopies; Correlation analysis; Cultivars; Drought resistance; Genotypes; Glycine max; Glycine max - growth & development; Glycine max - microbiology; Humanities and Social Sciences; Image processing; Infrared Rays; Inoculation; Light; multidisciplinary; Nodulation; Phenotype; Phenotyping; Photosynthesis; Plant Root Nodulation; Principal Component Analysis; Principal components analysis; Propanolamines - metabolism; Science; Science (multidisciplinary); Soil moisture; Soybeans; Strains (organisms); Symbiosis
• DOI: 10.1038/s41598-017-06441-3
• EISSN: 2045-2322

Symbiotic effectiveness of rhizobitoxine (Rtx)-producing strains of
Bradyrhizobium
spp. in soybean (cultivar NRC-37/Ahilya-4) under limited soil moisture conditions was evaluated using phenomics tools such as infrared(IR) thermal and visible imaging. Red, green and blue (RGB) colour pixels were standardized to analyse a total of 1017 IR thermal and 692 visible images. Plants inoculated with the Rtx-producing strains
B. elkanii
USDA-61 and USDA-94 and successive inoculation by
B. diazoefficiens
USDA-110 resulted in cooler canopy temperatures and increased canopy greenness. The results of the image analysis of plants inoculated with Rtx-producing strains were correlated with effective nodulation, improved photosynthesis, plant nitrogen status and yield parameters. Principal component analysis (PCA) revealed the reliability of the phenomics approach over conventional destructive approaches in assessing the symbiotic effectiveness of
Bradyrhizobium
strains in soybean plants under watered (87.41–89.96%) and water-stressed (90.54–94.21%) conditions. Multivariate cluster analysis (MCA) revealed two distinct clusters denoting effective (Rtx) and ineffective (non-Rtx)
Bradyrhizobium
inoculation treatments in soybean. Furthermore, correlation analysis showed that this phenotyping approach is a dependable alternative for screening drought tolerant genotypes or drought resilience symbiosis. This is the first report on the application of non-invasive phenomics techniques, particularly RGB-based image analysis, in assessing plant-microbe symbiotic interactions to impart abiotic stress tolerance.