Puccinia triticina pathotypes-THTT and THTS display complex transcript profiles on Thatcher

Background: Wheat leaf rust is an important disease worldwide. Understanding the Puccinia triticina f.sp tritici ( Pt ) pathogenic molecular mechanism and inconstant toxic region are highly important for managing the disease. The present study aimed to analyze pathogenic divergences between Pt isolates. Results: Total RNA was extracted from Thatcher infected by two Pt isolates, Tc361_1 (THTT) and Tc284_2 (THTS) at 144 hours post inoculation (hpi). The mRNA then was harvested and sequenced. Results indicated that a total of 2,784 differential expressed genes (DEGs) were detected. Forty-five genes were specifically expressed in THTT including transcription initiation factor, transmembrane transporter activity and so on, while 26 genes were specially expressed in THTS including GTPase activity, ABC transporter and so on. Fifty-four differential expressed candidate effectors were screened from the tow isolates. Two candidate effectors were chosen and validated on tabacco, and the result showed that they can inhibit the necrosis induced by Bax. qRT-PCR of 12 significantly different expressed genes were carried out to prove that the results of RNA-seq is similar to that of qRT-PCR at 144 hpi and show their expression level in the early stage and the difference between two Pt pathotypes. Conclusion: The results obtained in this study showed that the transcript profiles between THTT or THTS and Thatcher were very complicated.