| As an important oil crop,sunflower has extremely high economic value and is widely planted in China.However,the increasingly serious sunflower Verticillium wilt disease has severely restricted the development of the sunflower industry.However,unfortunately,there is currently no effective and effective agent that can prevent and control Verticillium dahliae.Therefore,it is very important to explore effective biological control methods and study its biocontrol mechanism to provide new ideas for controlling Verticillium dahliae in sunflower.1.It was the first time to clarify that strain Vn-1 can induce the cross-protection against sunflower verticillium wilt.In order to find the best conditions for cross-protection of strain Vn-1,interval days and induced concentration were optimized.Under the optimal conditions,it was conducted to test the persistence of the cross-protection and its effect on sunflower growth.The results showed that the optimized condition was 5 days as interval days and 1×10~6cfu/mL as induced concentration;under this condition the best control effect of strain Vn-1 against sunflower verticillium wilt was 72.27%,and it maintained over 30%of control effect after 44 day by challenge inoculation;Under the optimal condition plant height and root length of the sunflower were significantly improved,which indicated that strain Vn-1 can reduce the inhibitory effect of virulent strains on the growth of sunflower plants.2.The physiological and biochemical mechanism of the interaction of strain Vn-1 on Verticillium wilt was studied.It was found that strain Vn-1 can induce POD(peroxidase)and SOD(superoxide dismutase)in sunflower leaves.Increased activity of PAL(phenylalanine ammonia-lyase)and CAT(hydrogenase)all peaked at 24 or 48 hours,and strain Vn-1 was able to induce defensive enzyme activity higher than that of virulent Daoli Branch strain Vd-33.Vn-1 can induce the xylem thickening of sunflower hypocotyl,can invade sunflower leaves to resist the infection of Vd-33,and can induce the sunflower germ to resist the infection of Vd-33,the germination rate is increased by 6%,and the resistance to Vd-33 infestation Control effectiveness reached 44.43%.3.The RNA-seq sequencing technology was used to analyze the gene expression of sunflower induced by Vn-1 and Vd-33,and the differentially expressed genes of sunflower were induced by Verticillium dahliae which had different virulence.The average clean read average obtained for each process is 48439410,and the smallest amount of data is 6.19G.The percentage of sequencing sequences in the test treatment group to the reference genome was greater than 85.89%.The average clean read average obtained for each process is 48439410,and the smallest amount of data is 6.19G.The correlation R2 between all processing replicates was greater than 0.8 and the correlation was higher.The most significant 20 differentially expressed genes were up-regulated in young roots of sunflower24 h and 48 h after Vn-1 and Vd-33 inoculation.There are several genes associated with diseaseresistancesuchas:MYB4relatedproteingenes,xyloglucan endotransglucosylase/hydrolase protein genes,disease resistance related protein genes,and genes associated with calcium binding,withering Death-associated inhibitory enzymes,chitinase,transglutaminase,cell wall-associated receptor kinases,etc.GO analysis showed that Vn-1 induced sunflower resistance to Verticillium wilt is closely related to oxidoreductase activity and redox process,and lipid metabolism;Coenzyme factor binding;Regulation of nitrogen compound metabolism;Regulation of cell biosynthesis processes,etc.are also significant set. |
PDF Full Text Request