A conidiation-related gene is highly expressed at the resting urediospore stage in Puccinia striiformis f. sp. tritici

Abstract

The production and germination of asexual spores in a diverse group of fungi play a crucial role in their infection cycles. These processes are regulated by a set of genes, namely, conidiation-related genes, involved in the production, morphological characteristics, and differentiation of conidia. In this study, we identified and characterized the PsCon1 gene, which is the first conidiation-related gene identified in Puccinia striiformis f. sp. tritici (Pst). Sequence analysis revealed that PsCON1 has two conserved conidiation-specific protein 6 domains. Single nucleotide polymorphisms and insertion/deletion variations were detected in the coding region of PsCon1 among five Pst races. Quantitative RT-PCR assays revealed that PsCon1 was expressed at the highest level in resting urediospores of Pst, and gradually decreased after germination and infection. However, at 312hpi, at the stage of forming large amounts of urediospores on leaves, the amount of PsCon1 mRNA was sharply increased but only 0.1-fold that of resting urediospores. Subcellular localization assays indicated PsCon1 heterologously expressed in Fusarium graminearum was located in the cytoplasm of conidia. The results suggest that PsCon1 may play a role in formation or survival of Pst urediospores. © 2013.