A stripe rust fungal effector PstSIE1 targets TaSGT1 to facilitate pathogen infection

Abstract

SUMMARY Puccinia striiformis f. sp. tritici (Pst), the causal agent of stripe rust, is a destructive pathogen of Triticum aestivum (wheat), threatening wheat production worldwide. Pst delivers hundreds of effectors to manipulate processes in its hosts during infection. The SGT1 (suppressor of the G2 allele of skp1), RAR1 (required for Mla12 resistance) and HSP90 (heat‐shock protein 90) proteins form a chaperone complex that acts as a core modulator in plant immunity. However, little is known about how Pst effectors target this immune component to suppress plant immunity. Here, we identified a Pst effector PstSIE1 that interacts with TaSGT1 in wheat and is upregulated during the early infection stage. Transient expression of PstSIE1 suppressed cell death in Nicotiana benthamiana induced by VmE02 and PcNLP2. Transgenic expression of PstSIE1‐RNAi constructs in wheat significantly reduced the virulence of Pst. Overexpression of PstSIE1 in wheat increased the number of rust pustules and reduced the accumulation of reactive oxygen species (ROS), indicating that PstSIE1 functions as an important pathogenicity factor in Pst. PstSIE1 was found to compete with TaRAR1 to bind TaSGT1, thus disrupting the formation of the TaRAR1–TaSGT1 subcomplex. Taken together, PstSIE1 is an important Pst effector targeting the immune component TaSGT1 and involved in suppressing wheat defense.

Magnaporthe oryzae effector MoSPAB1 directly activates rice Bsr-d1 expression to facilitate pathogenesis

“…Although several studies reported cases where pathogen proteins compete with plant proteins for interactions with host proteins 26 – 28 , no reports of pathogen proteins competing with plant transcription factors to regulate host genes were available. Here, MoSPAB1 competes against rice MYBS1 for the ability to promote Bsr-d1 expression although they may simultaneously bind to the Bsr-d1 promoter (Fig.…”

The Biological Roles of Puccinia striiformis f. sp. tritici Effectors during Infection of Wheat

“…Recently, PstSIE1, an effector lacking any known sequence motifs, was discovered to compete for TaSGT1 binding. Consequently, this disrupted the formation of the TaRAR1–TaSGT1 subcomplex, a chaperone complex that acts as a core modulator in plant immunity, promoting pathogenesis [ 32 ].…”

Comparison of gene expression changes in two wheat varieties with different phenotype to strip rust using RNA-Seq analysis

“…RNA-seq technology has been widely used in wheat to cope with stress (Ma et al 2021;Zhang et al 2021;Lee et al 2022;Vranic et al 2022). At present, many candidate genes induced by stripe rust have been cloned and preliminarily analysed using RNA-seq, including TaWRKY, TaBCAT1, TaNAC30, TaEIL1, and TaSGT1 (Duan et al 2013;Wang et al 2018;Corredor-Moreno et al 2021;Wang et al 2022;Zhao et al 2022). These results have provided a foundation for further analysis of the interaction between stripe rust and wheat's resistance to rust at the molecular level.…”