Table 1

The information on primers used in this study"

Fig. 1

Cloning and structure analysis of HvMYB2 coding region from wild barley EC_S1 A: amplify the 912 bp HvMYB2 coding sequence from wild barley EC_S1; B: HvMYB2 gene structure analysis; C: conservative domain prediction in HvMYB2 protein."

Fig. 2

Prediction of phosphorylation sites of HvMYB2 protein in barley"

Fig. 3

Prediction of secondary structure of HvMYB2 protein"

Fig. 4

Prediction of the tertiary structure of HvMYB2 protein The different colored regions represent the confidence index pLDDT for protein prediction (a confidence index estimated by atom from 0 to 100, with higher values indicating higher confidence), where blue represents the highest confidence and red represents the lowest confidence regions."

Fig. 5

Phylogenetic analysis and sequence alignment of HvMYB2 and MYB family proteins in related species AEGTS: Aegilops tauschii; TRIUA: Triticum urartu; TRITD: Triticum turgidum; WHEAT: Triticum aestivum."

Fig. 6

Analysis of HvMYB2 expression pattern A: expression levels of HvMYB2 in different tissue parts and stages of barley. The data comes from the BarleyX database. EMB: four days embryos; ROO: roots from seedlings; ROO2: roots from seedlings (28 days); LEA: shoots from seedlings; INF1: young developing inflorescences; INF2: developing inflorescences; NOD: developing tillers; CAR5: developing grain (five days); CAR15: developing grain (fifteen days); ETI: etiolated seedling, dark cond.; LEM: inflorescences, lemma; LOD: inflorescences, lodicule; PAL: dissected inflorescences, palea; EPI: epidermal strips composed of upper spikelet ridges and lower leaf ridges; RAC: inflorescences, rachis; SEN: senescing leaves. B: expression levels of HvMYB2 in response to drought stress in different barley genotypes; C: subcellular location of HvMYB2 protein heterologous expression in tobacco leaves. Bright: white light; GFP: 488 nm excitation light source; DAPI: 4',6-diamidino-2-phenylindole, nuclear fuel, 340 nm excitation light source; Merged: three channels of white light, 488 nm, and 340 nm. The scale is 15 μm."

Fig. 7

Drought tolerance evaluation of HvMYB2-overexpressed Arabidopsis plants A: semi-quantitative analysis of HvMYB2 gene expression levels in HvMYB2-overexpressed strains, with Actin2 gene as an internal control gene. M: DL2000 marker; H2O: PCR negative control; WT: wild-type Arabidopsis, used as a control for transgenic Arabidopsis plants; 1-9: transgenic lines 1-9. B: phenotypes of wild-type and three HvMYB2-overexpressed Arabidopsis lines (OE2, OE4, OE9) after five days of drought stress. C: relative conductivity (REC). D: relative water content (RWC). E: stomatal conductance (Gs). F: chlorophyll a content (Chl a). G: chlorophyll b content (Chl b). The different lowercase letters on the error line indicate differences at the 5% significance level."

Fig. 8

Evaluation of drought tolerance of HvMYB2-silenced barley plants A: silencing of maker gene HvPDS in barley resulted in a photobleaching phenotype in leaves. Mock: barley plants inoculated with BSMV::γ (empty vector). The scale is 1 cm. B: the expression level of HvPDS was significantly reduced in HvPDS-silenced plants. C: the expression levels of HvMYB2 in barley plants inoculated with BSMV::γ (Mock) and BSMV::HvMYB2 (randomly selected three plants, VIGS1, VIGS2, VIGS3). D: phenotypes of barley plants inoculated with BSMV::γ (Mock) and BSMV::HvMYB2 after 7 days of well-watered and drought treatment. E: relative water content (RWC). F: relative electrical conductivity (REC). G: stomatal conductance (Gs). H: yellow leaf area ratio. The data are derived from three independent biological replicates, each consisting of 20 plants. The different lowercase letters on the error line indicate differences at the 5% significance level."

Fig. 9

Protein interaction network of HvMYB2"

Fig. 10

Analysis of cis-acting elements in HvMYB2 promoter A: distribution of cis-acting components; B: number of cis-acting components."

Fig. 11

Analysis of HvMYB2 promoter variation based on barley pan genome"

Table S1

Distribution of mutations in the promoters of pan genomic barley genotypes"

Fig. 12

Effect of promoter variation on transcriptional activity The pro-HvMYB2a type promoter doesn’t contain a sequence insertion of 181 bp; the pro-HvMYB2b type promoter includes a 181 bp sequence insertion, mainly for the promoter types of wild barley EC_S1 and B1K-04-12."