Table 1.
Libraries and sequences generated for the Carica papaya transcriptome.
Fig 1.
Morphological characterization of C. papaya plants under well-watered and WDS conditions.
Representative photographs showing plants from the Susceptible (S) (a) and Tolerant (T) (b) genotypes, either well-watered (SW and TW), or during a 14 d.p.t. period of WDS (SD and TD). The time of stress exposure (from left to right; 3, 7 and 14 d.p.t. after water withholding) is indicated.
Fig 2.
Measurement of physiological parameters in C. papaya plants under well-watered and WDS conditions.
Water potential (MPa) (a), Photosynthesis (μmol CO2 m-2 s-1) (b), Fv/Fm (c) and Electrolyte leakage (%) (d) in plants irrigated daily (day 0, well-watered Control plants; SW and TW), and when plants were exposed to WDS for 3, 7 and 14 d.p.t. (SD and TD). Data are means ± SD of 3 replicates (n = 9). Different letters indicate significant differences (p<0.05).
Table 2.
Metrics of the de novo transcriptome assembly of Carica papaya.
Fig 3.
Venn diagram for differentially expressed genes in both papaya genotypes under well-watered or WDS conditions.
Genes of reference transcriptome expressed in both genotypes under well-watered (SW and TW) or after they were subjected to WDS for 14 d.p.t. (SD and TD) (a). DEGs obtained for: SD vs SW (b), TD vs TW (c), TW vs SW (d) and TD vs SD (e). Numbers in each intersection represent the number of detected genes with at least one read (gene tag) in these intersections.
Fig 4.
Gene Ontology functional annotation of DEGs in SD vs SW and TD vs TW treatments.
GO Slim terms for Biological Process, Molecular Function, and Cellular Component assigned to up-regulated and down-regulated genes (%) found in (a) the susceptible C. papaya genotype under WDS for 14 d.p.t. compared to well-watered (SD vs SW). and (b) the wild tolerant C. papaya genotype under WDS for 14 d.p.t. compared to well-watered treatment (TD vs TW). GO associations were assigned by a BLASTX search against A. thaliana proteome.
Fig 5.
Gene Ontology Functional annotation of DEGs in TW vs SW and TD vs SD treatments.
GO Slim terms for Biological Process, Molecular Function, and Cellular Component assigned to up-regulated and down-regulated genes (%) from both C. papaya genotypes, when (a) well-watered (TW vs SW); or (b) when both genotypes were subjected to WDS for 14 d.p.t. (TD vs SD). GO associations were assigned by a BLASTX search against A. thaliana proteome.
Fig 6.
DEGs analysis in both C. papaya genotypes under well-watered or WDS conditions.
Hierarchical clustering of 283 transcripts of TF genes identified in the papaya transcriptome of both genotypes when well-watered (SW and TW) or when exposed to WDS for 14 d.p.t. (SD and TD). Red indicates down-regulated, green indicates up-regulated and black unchanged values, as shown on the color scale at the side of the figure a). Comparison of the DEGs number of 283 TF genes evaluated by up- and down-regulated in the papaya transcriptome of both genotypes, when well-watered (SW and TW) or when they were exposed to WDS for 14 d.p.t. (SD and TD) b).
Table 3.
TF genes associated to drought stress, that showed up-regulated differential expression in plants of the wild tolerant genotype exposed to 14 d.p.t. of WDS vs well-watered plants (TD vs TW), but down-regulated differential expression in the commercial susceptible genotype plants exposed to 14 d.p.t. of WDS vs well-watered plants (SD vs SW).
Fig 7.
DEGs analysis of 89 TF genes related to drought stress, selected according to their high number of transcripts per million (TPM) and high fold change rate.
Hierarchical clustering of 89 TF genes identified in the papaya transcriptome, based on the ratio between SD/TD, with fold change rates greater than 1.5 (p < 0.001). Red indicates down-regulated, green indicates up-regulated and black unchanged values, as shown on the color scale at the side of the figure a). Distribution by TF family of the number of DEGs from the 89 selected TF genes b). Fold Change of TF candidate genes selected, according to the ratio between SD/TD, to be validated by RT-qPCR c).
Fig 8.
Expression levels of six selected TF candidate genes from leaves of the two C. papaya genotypes when well-irrigated (day 0), or when exposed to 14 d.p.t. of WDS.
Red (S) and green (T) lines represent the expression level of transcripts per million (TPM) of the following 6 TF genes: CpHSF a), CpMYB b), CpNAC c), CpNFY-A d), CpERF e) and CpWRKY f). In the case of TPM data were transformed to Log 2 values. The red (S) and green (T) bars represent the Relative Expression Levels (REL) of the same genes determined by RT-qPCR, after 3, 7 and 14 of WDS. REL data are the means ± SD of three biological replicates. Different letters indicate significant differences.