论文题目：SmJAZs‐SmbHLH37/SmERF73‐SmSAP4 module mediates jasmonic acid signaling to balance biosynthesis of medicinal metabolites and salt tolerance in Salvia miltiorrhiza
论文作者：Bingbing Lv, Huaiyu Deng, Jia Wei, Qiaoqiao Feng, Bo Liu, Anqi Zuo, Yichen Bai, Jingying Liu, Juane Dong* and Pengda Ma*
论文摘要：
Salvia miltiorrhiza holds significant importance in traditional Chinese medicine. Stress-associated proteins (SAP), identified by A20/AN1 zinc finger structural domains, play crucial roles in regulating plant growth, development, resistance to biotic and abiotic stress, and hormone responses.
Herein, we conducted a genome-wide identification of the SAP gene family in S. miltiorrhiza. The expression analysis revealed a significant upregulation of SmSAP4 under methyl jasmonate (MeJA) and salt stress. Overexpressing SmSAP4 in S. miltiorrhiza hairy roots increased tanshinones content while decreasing salvianolic acids content, while RNAi-silencing SmSAP4 had the opposite effect. SmSAP4 overexpression in both Arabidopsis thaliana and S. miltiorrhiza hairy roots decreased their salt stress tolerance, accompanied by increased activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and a hindered ability to maintain the Na+/K+ ratio. Further investigations demonstrated that MeJA alleviated the inhibitory effect of SmJAZ3 on SmSAP4 activation by SmbHLH37 and SmERF73. However, MeJA did not affect the inhibition of SmSAP4 activation by SmJAZ8 through SmbHLH37.
In summary, our research reveals that SmSAP4 negatively regulates the accumulation of salvianic acid through the SmJAZs-SmbHLH37/SmERF73-SmSAP4 module and positively impacting the accumulation of tanshinones. Additionally, it functions as a negative regulator under salt stress.
茉莉酸(JAs)是重要的植物激素，影响植物的生长发育、生物和非生物胁迫的耐受性以及初级和次级代谢物的生物合成。在该研究中，作者发现盐胁迫可以增加丹参内源MeJA的含量，通过全基因组分析在丹参中鉴定了一个响应MeJA和NaCl处理的胁迫相关蛋白(SmSAP4)，SmSAP4负调控丹酚酸的合成并正调控丹参酮的合成。异源过表达SmSAP4降低了转基因拟南芥的耐盐性，此外，作者探究了SmSAP4的同源基因AtSAP2的功能，与野生型相比，拟南芥sap2突变体表现出更强的耐盐性。在丹参毛状根中检测了SmSAP4对植物耐盐性的影响，结果表明，过表达SmSAP4降低了丹参毛状根对盐胁迫的耐受性，RNA干扰具有相反的作用。SmbHLH37和SmERF73作为SmSAP4的上游调控因子调控SmSAP4的表达。SmJAZ3抑制SmbHLH37和SmERF73对SmSAP4的上调作用，外源添加MeJA使SmJAZ3降解，释放SmbHLH37进而上调SmSAP4表达。SmJAZ8抑制SmbHLH37对SmSAP4的上调，而外源添加MeJA时由于SmJAZ8缺失LPIARR基序而抑制了降解，无法释放SmbHLH37。该研究阐明了JA介导SmJAZs-SmbHLH37/SmERF73-SmSAP4模块平衡丹参药用活性成分和耐盐性的分子机制，这为今后应用基因工程培育优质、抗胁迫的丹参品种他提供了理论基础。
文章链接：https://doi.org/10.1111/nph.20110