Fig 1.
Phylogenetic analysis of NAC proteins from cassava and Arabidopsis.
A total of 96 NACs from cassava and 105 NACs from Arabidopsis were used to construct the NJ tree with 1000 bootstrap based on the full length sequences of NACs. The NAC proteins are grouped into 16 distinct subgroups (TERN, NAC2, ONAC022, ANAC011, NAC1, SENU5, ATAF, AtNAC3, NAP, NAM, TIP, OSNAC8, OSNAC7, ANAC001, ONAC003 and ANAC063).“ANACs”are the NAC proteins from Arabidopsis. “MeNACs” indicate the NAC proteins from cassava.
Fig 2.
The exon-intron structure of MeNAC genes according to the phylogenetic relationship.
The unrooted phylogenetic tree was constructed with 1000 bootstrap based on the full length sequences of MeNACs. Exon-intron structure analyses of MeNAC genes were performed by using the online tool GSDS. Lengths of exons and introns of each MeNAC gene were exhibited proportionally.
Fig 3.
Conserved motifs of MeNAC proteins according to the phylogenetic relationship.
The conserved motifs in the MeNAC proteins were identified by MEME. Grey lines represent the non-conserved sequences, and each motif is indicated by a colored box numbered at the bottom. The length of motifs in each protein was exhibited proportionally.
Fig 4.
Expression profiles of MeNAC genes in different tissues of two cassava accessions.
The transcript data generated from two replicates. The bar at the top of the heat map represents relative expression values.
Fig 5.
Expression profiles of MeNAC genes in leaves and roots of three cassava accessions after drought treatment.
The transcript data generated from two replicates. The relative expression values were log2 transformed. The bar at the top of the heat map represents relative expression values.
Fig 6.
Expression profiles of MeNAC genes in leaves under osmotic stress.
The relative expression levels of MeNAC genes in each treated time point were compared with that in each time point at normal conditions. NTC (no treatment control) at each time point was normalized as “1”. Data are means ± SE calculated from three biological replicates. Means denoted by the same letter do not significantly differ at P <0.05 as determined by Duncan’s multiple range test.
Fig 7.
Expression profiles of MeNAC genes in leaves under salt stress.
The relative expression levels of MeNAC genes in each treated time point were compared with that in each time point at normal conditions. NTC (no treatment control) at each time point was normalized as “1”. Data are means ± SE calculated from three biological replicates. Means denoted by the same letter do not significantly differ at P <0.05 as determined by Duncan’s multiple range test.
Fig 8.
Expression profiles of MeNAC genes in leaves under cold stress.
The relative expression levels of MeNAC genes in each treated time point were compared with that in each time point at normal conditions. NTC (no treatment control) at each time point was normalized as “1”. Data are means ± SE calculated from three biological replicates. Means denoted by the same letter do not significantly differ at P <0.05 as determined by Duncan’s multiple range test.
Fig 9.
Expression profiles of MeNAC genes in leaves under ABA treatment.
The relative expression levels of MeNAC genes in each treated time point were compared with that in each time point at normal conditions. NTC (no treatment control) at each time point was normalized as “1”. Data are means ± SE calculated from three biological replicates. Means denoted by the same letter do not significantly differ at P <0.05 as determined by Duncan’s multiple range test.
Fig 10.
Expression profiles of MeNAC genes in leaves under H2O2 treatment.
The relative expression levels of MeNAC genes in each treated time point were compared with that in each time point at normal conditions. NTC (no treatment control) at each time point was normalized as “1”. Data are means ± SE calculated from three biological replicates. Means denoted by the same letter do not significantly differ at P <0.05 as determined by Duncan’s multiple range test.
Fig 11.
Expression profiles of MeNAC genes in leaves under various stresses, ABA and H2O2 treatments.
Log2 based values from three replicates of qRT-PCR data were used to create the heatmap. The scale represents the relative signal intensity values. Relative expression values for each gene after various treatments are provided in Figs 6–10 and S7 Table.