Alternative splicing is a Sorghum bicolor defense response to fungal infection
This study provides new insights that alternative splicing participates with transcriptional control in defense responses to Colletotrichum sublineola in sorghum
In eukaryotic organisms, alternative splicing (AS) is an important post-transcriptional mechanism to generate multiple transcript isoforms from a single gene. Protein variants translated from splicing isoforms may have altered molecular characteristics in signal transduction and metabolic activities. However, which transcript isoforms will be translated into proteins and the biological functions of the resulting proteoforms are yet to be identified. Sorghum is one of the five major cereal crops, but its production is severely affected by fungal diseases. For example, sorghum anthracnose caused by Colletotrichum sublineola greatly reduces grain yield and biomass production. In this study, next-generation sequencing technology was used to analyze C. sublineola-inoculated sorghum seedlings compared with mock-inoculated control. It was identified that AS regulation may be as important as traditional transcriptional control during defense responses to fungal infection. Moreover, several genes involved in flavonoid and phenylpropanoid biosynthetic pathways were found to undergo multiple AS modifications. Further analysis demonstrated that non-conventional targets of both 5′- and 3′-splice sites were alternatively used in response to C. sublineola infection. Splicing factors were also affected at both transcriptional and post-transcriptional levels. As the first transcriptome report on C. sublineola infected sorghum, our work also suggested that AS plays crucial functions in defense responses to fungal invasion.
KeywordsMetabolic pathway Post-transcriptional regulation Splice site Splicing factor
This work was primarily supported by a research funding awarded to CL (GRF17123315) by the Hong Kong Research Grants Council (HKRGC). LW was supported by the HKU postgraduate fellowship. Additional funding included a grant (GRF CUHK12100318) awarded to JZ by the HKRGC.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflicts of interest.
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