In order to investigate the molecular function of B class heat shock transcription factors(HS-Fs)in heat tolerance of sesame,using the heat-tolerant cultivar Zhengtaizhi 3 as material,the SiHsfB-2b gene was cloned by homologous cloning method based on the gene sequence encoding the B class HSF protein Hs-fB2b identified by previous transcriptome analysis.Meanwhile,its bioinformatics analysis was conducted,its expression characteristics in different organs of sesame and under heat stress were analyzed,and also its sub-cellular localization.The results showed that the full length of SiHsfB-2b CDS was 936 bp,encoding 311 amino acids.The phylogenetic tree analysis showed that SiHsfB-2b was closely related to the homologous proteins of Phtheirospermum japonicum(Thunb.)Kanitz,Striga asiatica L.and Olea europaea subsp.cuspidata,and all they contained the conserved DNA-binding domains.Subcellular localization analysis revealed that the protein was located in nucleus.Furthermore,the promoter region of SiHsfB-2b gene contained 13 types of cis-acting elements,among which,3 types related to stress response and 3 types related to hormone response.The real-time quantitative PCR analysis showed that heat stress could induce the up-regulated expression of SiHsfB-2b in sesame roots,stems and leaves,and the highest relative expression level was observed in leaves.In re-sponse to continuous heat stress,the expression level of SiHsfB-2b in sesame stems and leaves exhibited an in-creasing trend,and the significant up-regulated expression was observed in leaves at the late stage of stress;but in roots,its expression exhibited increasing first and then decreasing.In conclusion,it was speculated that the SiHsfB-2b gene might positively respond to heat stress by mediating stress and hormone signaling pathways.These results could provide a theoretical basis for subsequent in-depth research on molecular mechanism of sesame resistant to heat.
维普
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