WRKY transcription factors regulate diverse biological processes in plants, including abiotic and biotic stress responses, and constitute one of the largest transcription factor families in higher plants. Although the past decade has seen significant progress towards identifying and functionally characterizing WRKY genes in diverse species, little is known about the WRKY family in sorghum ( Sorghum bicolor (L.) moench). Here we report the comprehensive identification of 94 putative WRKY transcription factors ( Sb WRKYs). The Sb WRKYs were divided into three groups (I, II, and III), with those in group II further classified into five subgroups (IIa–IIe), based on their conserved domains and zinc finger motif types. WRKYs from the model plant Arabidopsis ( Arabidopsis thaliana ) were used for the phylogenetic analysis of all SbWRKY genes. Motif analysis showed that all Sb WRKYs contained either one or two WRKY domains and that Sb WRKYs within the same group had similar motif compositions. SbWRKY genes were located on all 10 sorghum chromosomes, and some gene clusters and two tandem duplications were detected. SbWRKY gene structure analysis showed that they contained 0–7 introns, with most SbWRKY genes consisting of two introns and three exons. Gene ontology (GO) annotation functionally categorized SbWRKYs under cellular components, molecular functions and biological processes. A cis -element analysis showed that all SbWRKYs contain at least one stress response-related cis -element. We exploited publicly available microarray datasets to analyze the expression profiles of 78 SbWRKY genes at different growth stages and in different tissues. The induction of SbWRKYs by different abiotic stresses hinted at their potential involvement in stress responses. qRT-PCR analysis revealed different expression patterns for SbWRKYs during drought stress. Functionally characterized WRKY genes in Arabidopsis and other species will provide clues for the functional characterization of putative orthologs in sorghum. Thus, the present study delivers a solid foundation for future functional studies of SbWRKY genes and their roles in the response to critical stresses such as drought.

Bacterial spot caused by Xanthomonas vesicatoria is considered to be a major constraint of tomato production all over the world in particular warmer and humid parts.A disease disorder was reported in autumn season 2015within the Blue Nile State in Sudanaffecting all aerial parts of tomato plant. Symptomatic tomato leaves were collected and sent toPlant Pathology Laboratory, Faculty of Agriculture, University of Khartoum. An investigation on whether a phytopathogen was associated with symptoms of bacterial spots damage on tomato was conducted.The pathogen wasisolated and characterized morphologically, biochemically and at molecular level. The bacterium wasidentified as Xanthomonaseuvesicatoria and confirmed by PCR and sequence analysis of the 16S RNA gene (GenBankAccession Nos MH047248, MH051263 and MG686236).The disease incidence was remarkably high in ALrosserisand Aldamazein which recorded 49.27 and 52.17%, respectively, while the disease severity was 28.28 and 30.32%, respectively. To our knowledge, this is the first report of Xanthomonaseuvesicatoria causing bacterial spot disease in tomato in Sudan.

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