Preliminary Study On The Screening And Function Of Genes Related To Bursaphelenchusxylophilus By Enterobacter Ludwigii AA4

Pine wood nematode disease,also known as pine wilt disease(PWD),is a global forest disease caused by pine wood nematode(Bursaphelenchusxylophilus).Enterobacter ludwigii AA4 is a plant root-promoting bacteria isolated from plant roots.This study took E.ludwigii AA4 and B.xylophilus as the research objects.By evaluating the pine wood nematode activity of strain AA4,the related genes of AA4 B.xylophilus were determined and their correlation with nematicidal activity was verified,Preliminary analysis of the functions of the genes vgrG and ganA in AA4 killing B.xylophilus,and obtained the following research results:(1)Enterobacter ludwigii AA4 has the function of killing pine wood nematodeand controlling pine wood nematode.The stable colonization of strain AA4 in pine wood nematode is related to its activityinkilling B.xylophilus.(2)Thirteen mutants with significantly decreased nematicidal activity were obtained by screening the random mutant library of Enterobacter ludwigii AA4.Through the analysis of genome sequencing,we identified genepqi、impB、vgrG、ganA、PRK10693、tdk、ymiA、smvA、ycaP、PRK11824、barA、pro VandelaBare relatedtotheactivity inAA4 killing B.xylophilus.(3)The mutant strains AA4ΔvgrG,AA4ΔganA and complementary strains AA4ΔvgrG-C,AA4ΔganA-C of the genes vgrG and ganA were constructed by using homologous recombination technology.There is no difference between the mutant strain and the wild-type strain in growth in vitro.(4)The mutant strainsAA4ΔvgrGand AA4AganA had a significant decrease inactivityinkilling B.xylophilus and colonization ability.The mutant strains AA4ΔvgrG and AA4ΔganA motility,the biofilm forming ability ofAA4AganAaredecreased significantly.ThegenesvgrG and ganA of strain AA4 can affect the activity inAA4 killing B.xylophilusby changing the motility of bacteria,colonization in B.xylophilus,biofilm formation and motility of B.xylophilus.The above research results will lay a theoretical foundation for revealing the mechanism of E.ludwigiiAA4 killing pine wood nematode,and provide theoretical guidance for the development and efficient application of beneficial microbial preparations for preventing pine wood nematode disease.