PDF(Pubmed)
Abstract：
CONCLUSIONS: Transcription of PagMYB147 was induced in poplar infected by Melampsora magnusiana, and a decline in its expression levels increases the host\'s susceptibility, whereas its overexpression promotes resistance to rust disease. Poplars are valuable tree species with diverse industrial and silvicultural applications. The R2R3-MYB subfamily of transcription factors plays a crucial role in response to biotic stresses. However, the functional studies on poplar R2R3-MYB genes in resistance to leaf rust disease are still insufficient. We identified 191 putative R2R3-MYB genes in the Populus trichocarpa genome. A phylogenetic analysis grouped poplar R2R3-MYBs and Arabidopsis R2R3-MYBs into 33 subgroups. We detected 12 tandem duplication events and 148 segmental duplication events, with the latter likely being the main contributor to the expansion of poplar R2R3-MYB genes. The promoter regions of these genes contained numerous cis-acting regulatory elements associated with response to stress and phytohormones. Analyses of RNA-Seq data identified a multiple R2R3-MYB genes response to Melampsora magnusiana (Mmag). Among them, PagMYB147 was significantly up-regulated under Mmag inoculation, salicylic acid (SA) and methyl jasmonate (MeJA) treatment, and its encoded product was primarily localized to the cell nucleus. Silencing of PagMYB147 exacerbated the severity of Mmag infection, likely because of decreased reactive oxygen species (ROS) production and phenylalanine ammonia-lyase (PAL) enzyme activity, and up-regulation of genes related to ROS scavenging and down-regulation of genes related to PAL, SA and JA signaling pathway. In contrast, plants overexpressing PagMYB147 showed the opposite ROS accumulation, PAL enzyme activity, SA and JA-related gene expressions, and improved Mmag resistance. Our findings suggest that PagMYB147 acts as a positive regulatory factor, affecting resistance in poplar to Mmag by its involvement in the regulation of ROS homeostasis, SA and JA signaling pathway.
摘要：
结论：PagMYB147的转录在杨树感染magnusiana诱导，其表达水平的下降增加了宿主的易感性，而其过度表达促进对锈病的抗性。杨树是有价值的树种，具有多种工业和造林应用。转录因子的R2R3-MYB亚家族在响应生物胁迫中起着至关重要的作用。然而,杨树R2R3-MYB基因在抗叶锈病中的功能研究还不够。我们在毛果杨基因组中鉴定了191个推定的R2R3-MYB基因。系统发育分析将杨树R2R3-MYB和拟南芥R2R3-MYB分为33个亚组。我们检测到12个串联重复事件和148个节段重复事件，后者可能是杨树R2R3-MYB基因扩增的主要贡献者。这些基因的启动子区域含有许多与对胁迫和植物激素的反应相关的顺式作用调节元件。对RNA-Seq数据的分析鉴定了多个R2R3-MYB基因对Melampsoramagnusiana（Mmag）的反应。其中,PagMYB147在Mmag接种下显著上调,水杨酸（SA）和茉莉酸甲酯（MeJA）处理，其编码产物主要定位于细胞核。沉默PagMYB147加剧了Mmag感染的严重程度，可能是由于活性氧（ROS）产生和苯丙氨酸解氨酶（PAL）酶活性降低，以及与ROS清除相关的基因的上调和与PAL相关的基因的下调，SA和JA信号通路。相比之下,过表达PagMYB147的植物表现出相反的ROS积累，PAL酶活性，SA和JA相关基因表达，和改善Mmag抗性。我们的研究结果表明，PagMYB147作为一个积极的调节因素，通过参与ROS稳态的调节来影响杨树对Mmag的抗性，SA和JA信号通路。
