Comparative Transcriptomics Analysis Of Two Hosts-induced Verticillium Dahliae Isolates From Cotton And Sunflower

Verticillium dahliae is a soil-borne fungus that causes vascular wilt diseases through initiating plant root infection in a broad range of plants.V.dahliae is difficult to control because of the sustained viability of the resting structure microsclerotium,extensive host range,presence in the vascular system,and absence of effective fungicides.Thus,it is urgent that we focus on the molecular mechanism of V.dahliae–host interaction.In this study,next generation sequencing technology of RNA-seq was employed to investigate gene expression of two V.dahliae isolates from cotton and sunflower when both of the isolates were induced by cotton root and sunflower root,respectively.The identified differential expressed genes screened from two isolates will provide us important information to elucidate the molecular mechanism of V.dahliae–host interaction.1.The V.dahliae isolates from cotton and sunflower were cultured in liquid czapek–dox medium respectively for 72 hours.The results of comparative transcriptomics analysis showed that 583 genes were exclusively expressed in the V.dahliae isolate from cotton,however,724 genes were exclusively expressed in the the V.dahliae isolate from sunflower.The V.dahliae isolate from cotton was cultured in liquid czapek–dox medium in the presence of cotton roots for 72 hours.A total of 42 genes(pvalue < 0.05)in V.dahliae were differentially expressed when compared to cultured in liquid czapek–dox medium,indicating these genes were induced expressed by cotton root.Among them,20 genes were up-regulated,22 genes were down-regulated.Furthermore,6 genes(padj<0.05)were induced expressed significantly by cotton root.The V.dahliae isolate from sunflower was cultured in liquid czapek–dox medium in the presence of cotton roots for 72 hours.A total of 79 genes(pvalue< 0.05)in V.dahliae were differentially expressed when compared to cultured in liquid czapek–dox medium,indicating these genes were induced expressed by sunflower root.Among them,28 genes were up-regulated,51 genes were down-regulated.Furthermore,35genes(padj<0.05)were induced expressed significantly by sunflower root.Based on GO and KEGG analysis,the results showed that the 42 differnetially-expressed genes in V.dahliae from cotton were involved in amino acid metabolism,carbohydrate metabolism,energy metabolism,integral membrane component;79 differnetially-expressed genes in V.dahliae from sunflower were involved in amino acid metabolism,energy metabolism,biosynthesis of secondary metabolites,integral membrane component,hydrolytic enzyme activity,transferase activity,and binding activity.These data suggested that the differnetially-expressed genes may be associated in host specificity of V.dahliae isolates.2.The V.dahliae isolates from cotton and sunflower were cultured in liquid czapek–dox medium in the presence of cotton roots respectively for 72 hours,respectively.The results of comparative transcriptomics analysis showed that 55 up-regulated genes and 101down-regulated genes were expressed exclusively in the V.dahliae isolate from cotton;154up-regulated genes and 209 down-regulated genes were expressed exclusively in the V.dahliae isolate from sunflower.In addition,VdSC1 gene was up-regulated in sunflower V.dahliae,however,down-regulated in cotton V.dahliae;and VdSC2 gene was up-regulated in cotton V.dahliae,however,down-regulated in sunflower V.dahliae.The V.dahliae isolates from cotton and sunflower were cultured in liquid czapek–dox medium in the presence of sunflower roots respectively for 72 hours,respectively.The results of comparative transcriptomics analysis showed that 212 up-regulated genes and 260 down-regulated genes were exclusively expressed in the V.dahliae isolate from sunflower;90 up-regulated genes and117 down-regulated genes were exclusively expressed in the V.dahliae isolate from cotton;In addition,VdSC3,VdSC4 and VdSC5 genes were up-regulated in sunflower V.dahliae,however,down-regulated in cotton V.dahliae;and VdSC6 gene was up-regulated in cotton V.dahliae,however,down-regulated in sunflower V.dahliae.The sunflower V.dahliae was cultured in liquid czapek–dox medium in the presence of cotton and sunflower roots for 72 hours,respectively.The results of comparative transcriptomics analysis showed that 348up-regulated genes and 180 down-regulated genes were exclusively expressed in the presence of sunflower roots;108 up-regulated genes and 115 down-regulated genes were exclusively expressed in the presence of cotton roots;VdSC7 gene was up-regulated in the presence of cotton roots,however,down-regulated in the presence of sunflower roots.The cotton V.dahliae was cultured in liquid czapek–dox medium in the presence of cotton and sunflower roots for 72 hours,respectively.The results of comparative transcriptomics analysis showed that 50 up-regulated and 56 down-regulated genes were exclusively expressed in the presence of cotton roots;88 up-regulated and 86 down-regulated genes were exclusively expressed in the presence of sunflower roots.Based on GO and KEGG analysis,the results showed that VdSC4 was involved in sulfur relay system,gene VdSC5 was involved in transmembrane transport,and gene VdSC7 was involved in transcription factor.These data suggested that there were genes involved in host perference of V.dahliae isolates from cotton and sunflower.