Putative orthologs of Emphasis Type="Italic"Usti

Authors: Leonard Barnabas N M R Ashwin A Ramesh Sundar P Malathi R Viswanathan

Publish Date: 2017/02/25

Volume: 46, Issue: 2, Pages: 147-156

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Abstract

Smut caused by Sporisorium scitamineum is one of the most economically important diseases of sugarcane In order to comprehend smut resistance in sugarcane pathogenic determinants of this intriguing smut fungus need to be identified However the knowledge on molecular mechanisms behind its pathogenicity is inadequate and none of the predicted putative effectors of this smut fungus has been functionally characterised Based on the established close genomic synteny between S scitamineum and Ustilago maydis in this preliminary study we have identified putative orthologs of functionally characterised U maydis effectors viz Pep1 Cmu1 Tin2 Srt1 Stp1 and Pit1 in S scitamineum genome using blast based searches Further in silico analysis revealed that the identified candidate S scitamineum orthologs share higher sequence identity with Sporisorium reilianum than U maydis sequences Signal peptides transmembrane and other conserved domains predicted in the identified putative S scitamineum effector orthologs were consistent with the reported U maydis effectors In addition most of the identified putative effector orthologs of S scitamineum also shared considerable homology with the sequences of other closelyrelated smut fungi and codon sites with evidence of positive selection and episodic diversifying selection were detected in a few sequences Temporal gene expression analysis revealed that transcript expression of the identified putative S scitamineum effector orthologs increased significantly after 3 days post inoculation and was expressed in distinct patterns throughout the infection cycle The results of this study also indicate that these candidate effectors could be conserved among other closely related smut fungi

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