Pst germ tube sRNAs
The total RNAs of puccinia striiformis f.sp tritici germ tube were extracted using the mirVana miRNA isolation Kit (Ambion) according to the manufacturer’s instruction. sRNAs of Pst between 18~30 nucleotides were isolated using denatured polyacrylamide gel electrophoresis (PAGE), RNA oligonucleotides labeled at positions 18 and 30 were used as size standards. After ligated to5' and 3' adapters, the sRNAs were reverse transcribed to cDNA using RT-PCR reaction. The PCR products were sequenced with an Illumina Genome Analyzer (BGI, Shenzhen, China)