Diversity And Main Pathogenic Types Of Pathogen Isolates From Potato Scab In Inner Mongolia Province

The potato is the fourth largest food crop in the world.In recent years,the high nutritional value of the potato has been recognized by the world.Its vitamin C content is the highest among vegetables and it is also one of the anti-aging foods.Therefore,it is known as the second bread for human beings."Second bread" is also considered to be the new staple of China in the future.In last few years,scabs have been aggravated in many potato production areas in China,seriously affecting the economic value and commodity value of potato.This study was to isolate pathogens of potato common scab in different regions of Inner Mongolia and identify the genotypes of pathogenic gene,morphology,physiology,biochemistry and molecular biology of pathogenic bacteria,and pass the radish seedling test and tuber slice assay.Tablets and pot experiments were used to test the pathogenicity of isolated pathogens.Draw the following conclusions:(1)There are four main types of potato scab lesions in Inner Mongolia,which are concave lesions,convex lesions,flat lesions,and reticular lesions.The concave lesions are deep and shallow,about 2-5mm deep.The surface of the flat lesion was slightly depressed,and some of them even formed a patch and the surface showed a cracked state.The surrounding epidermis slightly showed an inconspicuous corkification bulge.Convex lesions indicate the formation of raised lesions,and the top of the lesion is severely corked.The reticular lesions are reticulated on the surface of the potato and the corkification is not severe compared to other types of lesions.(2)A total of 326 actinomycetes were screened out in 54 samples of potato which was infected scab in Inner Mongolia Province,including 30 in Chifeng,16 in Baotou,80 in Hohhot,152 in Ulanqab,and 48 in Hulunbeier.Among them,129 strains of pathogenic Streptomyces spp.,including Streptomyces scabies,Streptomyces turgidiscabies,Streptomyces bobili,Streptomyces galilaeus,Streptomyces europaeiscabies,Streptomyces diastatochromogenes,were identified.The main distribution of pathogenic bacteria: 7 in Chifeng,55 in Hohhot,62 in Ulanqab and 5 in Hulunbeier.(3)Detection of the three pathogenic genes txtAB,nec1,and tomA on pathogenicity islands(PAI)revealed that genotypes are diverse,with genotypes of txtAB+/nec1+/tomA+,txtAB-/nec1+/tomA-,and txtAB-/ nec1+/tomA+.(4)Several strains of representative strains were selected from the isolated pathogens for radish seedling test and tuber slice assay method.It was found that the tested strains could inhibit the growth of radish seedlings and could cause the tuber slices to be necrotic.And in the pot experiment,the potato produced scab symptoms,due to the potato suffering from potato scab.