Identification of DEGs Under Drought Stress Treatment
RNA-seq was used to detect DEGs in the soybean roots of DTP, DSP, DTL &
DSL genotypes subjected to drought stress at germination stage. By
comparing the genes showing differential expression under drought
stress, a total of 2325, 3060, 2525 and 3212 DEGs (including both up-
and down-) were found in the pairwise comparisons of DTP, DSP, DTL and
DSL, respectively under drought treatment vs. control by using log2FC≥2
and q value ≤ 0.05 (Fig. 2A). Hence, Sensitive genotypes
viz., DSP and DSL showed higher number of DEGs as compared to tolerant
genotypes DTP & DTL (Fig. 2A). Moreover, in sensitive
genotypes there are more number of down-regulated genes compared to
tolerant genotypes. By comparing the transcriptome profiles of four
genotypes, it was observed that total of 676, 493, 510 and 700 DEGs were
uniquely and uniformly expressed in DTP, DSP, DTL and DSL, respectively
under drought stress treatment (Fig. 2B ). In addition, 775 DEGs
were common among all four genotypes.
Further, we analyzed overlapping DEGs among 12 different combinations of
four genotypes under drought and control conditions using Circos
software (Fig. 2C). This analysis indicates that a major
fraction of DEGs were unique under stress condition compared to control
in all 12 combinations. Highest number of common DEGs (1950) among all
genotype combination were found between tolerant genotypes combination
under stress and control conditions (DTP-T vs DTL-T & DTP-C vs DTL-C),
whereas it was only 550 between sensitive genotypes under stress and
control conditions (DSP-T vs DSL-T & DSP-C vs DSL-C). In addition,
higher number of unique DEGs (2847) were found in sensitive genotypes
under drought stress (DSP-T vs DSL-T) compared to only 2095 in tolerant
genotypes (DTP-T vs DTL-T). These findings are in agreement with DEG
data and venn-diagram analysis, and revealed that sensitive genotypes
are more influenced by drought stress compared to tolerant genotypes at
the transcriptomic/gene expression level.