Heat shock protein 90 (Hsp90) is widely involved in plant growth and development, and plays critical roles in regulating thermotolerance and responses to high-temperature stress in plants. In this study, 18 TaHsp90 genes were identified in wheat via bioinformatic analysis and designated TaHsp90-2A to TaHsp90-7D-2 according to their chromosomal locations. Chromosomal localization revealed that TaHsp90 genes were unevenly distributed across nine wheat chromosomes. Analysis of gene structures and conserved motifs divided this gene family into two structural types, all of which harbored ten conserved motifs. Intraspecific collinearity analysis of wheat identified 23 collinear gene pairs. Phylogenetic tree analysis classified the Hsp90 gene families of all tested species into three subgroups. Promoter cis-acting element detection identified a total of 31 types of cis-elements in the TaHsp90 family. Haplotype analysis indicated that individual TaHsp90 members exhibited significant differences in haplotype number, frequency, and geographical preference, with obvious signatures of adaptive differentiation. Expression profiling revealed distinct tissue-specific and drought-heat-induced expression patterns among TaHsp90 members, which could be categorized into four stress-response modes and six tissue-expression modes. Quantitative real-time PCR (qRT-PCR) of six representative genes with typical stress-responsive patterns demonstrated that TaHsp90-2B exhibited the most prominent heat-inducible expression. Under normal growth conditions, there were no obvious phenotypic differences between carrying TaHsp90-2B wheat lines and wild-type plants. However, after exposure to 42 ℃ heat stress, the overexpression lines exhibited milder wilting and lodging, accompanied by significantly higher SPAD values as well as SOD, POD, and CAT activities compared with the wild type. These results indicate that this gene can markedly improve wheat tolerance to heat stress.
| 科 Family | 属数 Number of genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) | 属 Genus | 种数 Number of species | 占总种数比例 Percentage of total species (%) |
|---|---|---|---|---|---|---|
| 鹅膏菌科Amanitaceae | 2 | 11 | 5.26 | 鹅膏菌属 Amanita | 10 | 4.78 |
| 小菇科 Mycenaceae | 2 | 12 | 5.74 | 丝盖伞属 Inocybe | 5 | 2.39 |
| 多孔菌科 Polyporaceae | 8 | 14 | 6.70 | 蜡蘑属 Laccaria | 5 | 2.39 |
| 红菇科 Russulaceae | 3 | 23 | 11.00 | 小皮伞属 Marasmius | 6 | 2.87 |
| 小菇属 Mycena | 11 | 5.26 | ||||
| 光柄菇属 Pluteus | 5 | 2.39 | ||||
| 红菇属 Russula | 17 | 8.13 | ||||
| 栓菌属 Trametes | 5 | 2.39 |