High-throughput RNA sequencing reveals differences between the transcriptomes of the five spore forms of Puccinia striiformis f. sp. tritici, the wheat stripe rust pathogen

Abstract

The devastating wheat stripe (yellow) rust pathogen, Puccinia striiformis f. sp. tritici (Pst), is a macrocyclic and heteroecious fungus. Pst produces urediniospores and teliospores on its primary host, wheat, and pycniospores and aeciospores are produced on its alternate hosts, barberry (Berberis spp.) or mahonia (Mahonia spp.). Basidiospores are developed from teliospores and infect alternate hosts. These five spore forms play distinct roles in Pst infection, disease development, and fungal survival, etc. However, the specific genes and mechanisms underlying these functional differences are largely unknown. In this study, we performed, for the first time in rust fungi, the deep RNA sequencing to examine the transcriptomic shift among all five Pst spore forms. Among a total of 29,591 identified transcripts, 951 were specifically expressed in basidiospores, whereas 920, 761, 266, and 110 were specific for teliospores, pycniospores, aeciospores, and urediniospores, respectively. Additionally, transcriptomes of sexual spores, namely pycniospores and basidiospores, showed significant differences from those of asexual spores (urediniospores, teliospores, and aeciospores), and transcriptomes of urediniospores and aeciospores were more similar to each other than to the three other spore forms. Especially, the basidiospores and pycniospores which infected the berberis shows wide differences in the cell wall degrading-enzymes and mating and pheromone response genes. Besides, we also found that there are 6234 differential expressed genes between the urediniospores and pycniospores, while only have 3 genes have alternative splicing enents, suggesting that differential genes expression may make more contribution than AS. This comprehensive transcriptome profiling can substantially improve our understanding of the developmental biology of the wheat stripe rust fungus.

Genome biology and evolution of mating type loci in four cereal rust fungi

“…Importance of MAT loci in sexual reproduction were well established for Pt and Pst (18, 73), yet it is unclear if they are expressed and functional during the asexual reproduction on cereal hosts as found in Pt (18). Hence, we investigated the expression patterns of MAT genes in Pca , Pgt and Pst using publicly available RNA-seq infection time series of their cereal hosts (38, 41, 48, 74) (S2 Table).…”

Genome biology and evolution of mating-type loci in four cereal rust fungi

“…Importance of MAT genes in mate compatibility is well established for Pt and Pst [ 19 , 82 ], yet it is unclear if they are expressed and functional during asexual reproduction on cereal hosts as found in Pt [ 19 ]. Hence, we investigated the expression patterns of MAT genes in Pca , Pgt and Pst using publicly available RNA-seq infection time series of their cereal hosts [ 43 , 46 , 53 , 83 ] ( S2 Table ).…”

“…tritici and M . larici-populina [ 19 , 40 , 82 , 94 ], MAT genes are expressed during the sexual and asexual infection cycle. Suppression of MAT gene expression in P .…”

Molecular Mechanisms of the Stripe Rust Interaction with Resistant and Susceptible Wheat Genotypes

“…Simultaneous transcriptome sequencing of plant and pathogen can provide insights into genome-wide Pst –wheat interactions [ 8 , 9 , 10 , 11 , 12 ]. Several attempts have been made, up to date, to understand stripe rust gene expression: urediniospores cDNA library characterization [ 13 ], isolated haustoria and infected tissue analysis [ 14 ], germinated urediniospores versus haustorial transcriptome [ 15 ], and microarray transcript analysis of compatible versus incompatible Pst –wheat interactions [ 16 ], as well as the analysis of whole-genome transcriptomes of both wheat and stripe rust pathogen during infection using a dual RNA sequencing (RNA-seq) method [ 17 , 18 ].…”