| Sunflower is the second largest oil crop in the world.At present,the cultivation area in China is second only to soybeans and rapeseed,and is the third largest oil crop.It not only has ornamental value and medicinal value,but also has very important economic value.China is the fourth largest sunflower-growing country in the world,and Inner Mongolia is the largest sunflower-growing province in China.Sunflower Verticillium Wilt is a worldwide disease caused by Verticillium dahliae.It has become the most widespread and most harmful disease on sunflowers in my country.The use of attenuated strains to prevent and control plant diseases has attracted the attention of researchers,and it has the advantages of non-toxic and no pollution to the environment.Preliminary studies have shown that Verticillium from different sources have significant differences in the pathogenicity of sunflowers,and it has been confirmed that attenuated strains can enhance the resistance of sunflowers to Verticillium wilt.This study further verified that the attenuated Verticillium strains enhance the resistance of sunflower against Verticillium wilt,and focused on the molecular mechanism of its enhanced resistance,that is,through transcriptome sequencing and bioinformatics analysis,to screen out functional genes related to disease resistance.And clone the full length of the c DNA coding region of disease resistance-related genes to determine the target functional gene,and then verify the function through transient expression model plants.In this study,the attenuated strain Vn-1 was used as the research material.The attenuated sunflower root tissue was sequenced through transcriptome sequencing,and the sequencing results were used for transcriptome analysis.The results showed that,compared with the control group,the three GO functional items related to oxidoreductase in the Vn-1 group were significantly enriched.In addition,33 resistance genes and 160 susceptibility genes were predicted.The analysis results showed that 7 transcription factors(TFs),2 phytohormone response factors,2 E3 ubiquitin protein ligases,2CCR4-related factors and 2 predicted leucine-rich repeat(LRR)receptors were involved Sunflower is resistant to Verticillium wilt.We preferentially screened 4 resistance genes(Hann XRQ＿Chr14g0444761,Hann XRQ＿Chr04g0125131,Hann XRQ＿Chr02g0053931,Hann XRQ＿Chr03g0084521)from the candidate genes for gene function verification.The plant binary expression vector was constructed by In-Fusion and transformed into Agrobacterium leaves by GV3101.The injection was transiently expressed in Nicotiana benthamiana.After 48 hours of inoculation with Botrytis cinerea strain SCDD2,the relative diseased area of the leaves was counted.The results showed that the relative diseased area(71.05%,62.61%,69.31%,72.18%)after the resistance gene was transformed,were greater than those in the CK group(34.04%),indicating that the 4resistance genes negatively regulate tobacco resistance to Botrytis cinerea;5 days after inoculation with Phytophthora infestans,the relative lesion area(1.03%,1.06%,5.14 %,3.51%)were significantly lower than the CK group(67.15%),indicating that the 4resistance genes positively regulate tobacco resistance to Phytophthora infestans.In this study,through transcriptome data analysis and gene function verification,the relevant resistance genes of sunflower against Verticillium wilt were screened out,laying a theoretical foundation for the follow-up comprehensive study of relevant disease resistance mechanisms,and it is of great significance to the research of sunflower resistance genes. |
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