Phosphorus is one of the three key nutrients, essential for plant growth and development, with phosphate deficiency posing a common nutritional stress. In the context of responding to low phosphorus stress, several members of the MYB-CC gene family are recognized for their crucial regulatory functions. However, there is a lack of prior research on the MYB-CC gene family and its function reported in Salvia miltiorrhiza. We identified 18 genes in S.miltiorrhiza, distributed across eight chromosomes. Evolutionary analysis showed that both fragment duplication and whole genome duplication (WGD) serve as the principal mechanisms driving the expansion of the SmMYB-CC gene family. The promoters of SmMYB-CC contain cis-acting elements associated with a range of physiological processes such as abiotic stress, hormone signaling as well as growth and development. Analyses of transcriptome data obtained from different phosphorus concentration treatments have indicated that the expression levels of the SmMYB-CC7 increase in both shoot and roots. Moreover, SmMYB-CC7 demonstrates transcriptional activation activity, and is localizes within the nucleus, with no apparent alterations in subcellular localization observed in the response to low phosphorus conditions. Furthermore, the expression of SmMYB-CC7 in the Arabidopsis thaliana mutant phr (SmMYB-CC7-GFP/phr) is shown to partially retain the phenotype under low phosphorus conditions. Under conditions of low phosphorus stress, the expression of Pi starvation-induced (PSI) gene in SmMYB-CC7-GFP/phr exhibited a significant induction compared to the phr mutant. The identification of the SmMYB-CC gene family and the validation of SmMYB-CC7 function contribute significantly to the broader understanding of phosphate starvation signaling in S.miltiorrhiza.

Salvia miltiorrhiza Bunge (Danshen) is a traditional Chinese herb with significant medicinal value. The yield and quality of Danshen are greatly affected by climatic conditions, in particular high temperatures. Heat shock factors (Hsfs) play important regulatory roles in plant response to heat and other environmental stresses. However, little is currently known about the role played by the Hsf gene family in S. miltiorrhiza. Here, we identified 35 SmHsf genes and classified them into three major groups: SmHsfA (n = 22), SmHsfB (n = 11), and SmHsfC (n = 2) using phylogenetic analysis. The gene structure and protein motifs were relatively conserved within subgroups but diverged among the different groups. The expansion of the SmHsf gene family was mainly driven by whole-genome/segmental and dispersed gene duplications. The expression profile of SmHsfs in four distinct organs revealed its members (23/35) are predominantly expressed in the root. The expression of a large number of SmHsfs was regulated by drought, ultraviolet, heat and exogenous hormones. Notably, the SmHsf1 and SmHsf7 genes in SmHsfB2 were the most responsive to heat and are conserved between dicots and monocots. Finally, heterologous expression analysis showed that SmHsf1 and SmHsf7 enhance thermotolerance in yeast. Our results provide a solid foundation for further functional investigation of SmHsfs in Danshen plants as a response to abiotic stresses.

14-3-3 proteins are important proteins in plants, as they regulate plant growth and development and the response to biotic or abiotic stresses. In this study, a 14-3-3 gene(GenBank accession: OM683281) was screened from the cDNA library of the medicinal species Salvia miltiorrhiza by yeast two-hybrid and cloned. The open reading frame(ORF) was 780 bp, encoding 259 amino a cids. Bioinformatics analysis predicted that the protein was a non-transmembrane protein with the molecular formula of C_(1287)H_(2046)N_(346)O_(422)S_9, relative molecular weight of 29.4 kDa, and no signal peptide. Homologous sequence alignment and phylogenetic tree analysis proved that the protein belonged to 14-3-3 family and had close genetic relationship with the 14-3-3 proteins from Arabidopsis thaliana, Oryza sativa, and Nicotiana tabacum. The 14-3-3 gene was ligated to the prokaryotic expression vector pGEX-4 T-1 and then transformed into Escherichia coli BL21 for the expression of recombinant protein. Real-time fluorescent quantitative PCR showed that the expression of this gene was different among roots, stems, leaves, and flowers of S. miltiorrhiza. To be specific, the highest expression was found in leaves, followed by stems, and the lowest expression was detected in flowers. S. miltiorrhiza plants were treated with 15% PEG(simulation of drought), and hormones salicylic acid, methyl jasmonate, and ethephon, respectively, and the expression of 14-3-3 gene peaked at the early stage of induction. Therefore, the gene can quickly respond to abiotic stresses such as drought and plant hormone treatments such as salicylic acid, jasmonic acid, and ethylene. This study lays the foundation for revealing the molecular mechanism of 14-3-3 protein regulating tanshinone biosynthesis and responding to biotic and abiotic stresses.

为揭示小分子热激蛋白在丹参抵御逆境胁迫和有效成分积累的分子机制,根据橙根丹参转录组测序结果并结合RT-PCR技术在丹参中克隆获得一个小分子热激蛋白基因,其开放阅读框长度为585 bp,编码194个氨基酸,根据该基因编码的蛋白分子质量命名为SmHSP21.8.根据氨基酸多重序列比对和系统进化树分析,SmHSP21.8属于小分子热激蛋白的内质网亚族,并含有内质网小分子热激蛋白N端保守基序DPFR-I/V-LE-H/Q-x-P.构建原核表达载体pMAL-c2X-SmHSP21.8,并转化至大肠杆菌BL21感受态细胞,经诱导,成功表达出目的蛋白.时空表达分析表明,该基因在花中表达量最高,有显著的组织特异性.经38℃、PEG6000、脱落酸(abscisic acid,ABA)和吲哚-3-乙酸(indole-3-acetic acid,IAA)的诱导,该基因的相对表达量均有提高,表明SmHSP21.8参与了丹参幼苗对非生物胁迫高温、干旱,以及外源激素ABA和IAA响应的过程,为进一步研究小分子热激蛋白参与丹参响应逆境的分子机制奠定了基础.