التشخيص الجزيئي للبكتريا المسببة لمرض التعفن الطري على البطاطا في محافظتي كربلاء وبابل ومقاومتها بإستعمال بعض العوامل الاحيائية و المركبات النانوية

Molecular identifration of bacteria causing soft rot on potatoes in Karbala and Babylon Provinces and control it using some biological factors and nano-compounds.

This study aimed to isolate and diagnose the bacteria that cause soft rot on potato in some fields, stores and markets in the Provinces of Karbala and Babylon, test its pathogenicity on tobacco leaves and potato slices, test the sensitivity of a number of potato varieties grown in Iraq to infection with this bacteria, determine the family range of the Pathogenic bacteria. and Finaly, the study objected for evaluation of the effectiveness of a number of biological control agents, chemical pesticides, nano-materials, and their integration in combating disease in vitro and under greenhouse conditions. The experiments of this study were carried out in the Department of Plant Protection / College of Agriculture / University of Kerbala during the agricultural season of 2020-2021
The results of the isolation showed that 15 bacterial isolates were obtained from infected tubers Showed soft rot disease from all fields, storage and markets samples in Kerbala and Babylon Provinces. The pathogenic ability of this bacteria on tobacco leaves and potato slices proved that all the isolates were capable of causing the disease. isolates Pcc1, Pcc 6, Pcc9, Pcc11, and Pcc13 exceeded other isolates in the speed of symptoms on tobacco leaves, and their pathogenicity on potato slices, where the diameter of the affected tissues reached 4.7, 4.37, 4.5, 4.37, 4.5, Cim respectively.
The results of Morphologcal and biochemical examinations indicated that the bacteria was Pectobacterium carotovorum subsp. carotovorum and this diagnosis was confirmed by polymerase chain reaction (PCR). The results of the analysis of the nuclotide sequences of the PCR-amplified products and using the BLAST program (Basic Local Alignment Search Tool) showed that Pcc1 isolate belonged to the bacterium P. carotovorum subsp. carotovorum, which is genetically different from the same isolates belonging to these species. Therefore it was registered in the National Center for Biotechnology Information (NCBI), under the number MW453066.
The sensitivity test of some accession of potato cultivars to the infection by isolate Pcc1 showed that the Arezona was the most sensitive variety to infection as it was significantly superior to the other varieties through the affected tissue size reached 8.60 cm3.and The results of the family range disolyed that the bacterial isolate Pcc1 has the ability to cause the disease on potatoes, eggplant, turnip, beetroot, onion, Pumpkin, broccoli, cucumber, radish, and carrot with varying proportions.
The laboratory results of the antagonistic ability test between a number of biological factors and the pathogenic bacteria that causes soft rot disease using NA culture media and on potato slices showed that Trichoderma harzianum significantly (0.05)exceeded the other factors with an inhibition percentage reached 86.41 and 81.77% respectively.
As well as the results of testing the efficiency of a number of chemical pesticides against P. carotovorum subsp. carotovorum (at recommended concentrations), achieved an inhibition rate of 100% for the pesticides: Beltanol, Ganger, and Goldston that were significantly superior to Nordox, which had an inhibition rate of 21.56%. The results also revealed the superiority of nano-magnesium oxide in its inhibition of pathogenic bacteria over nano-ZnO in of for all concentrations used.
The control results P. carotovorum subsp. carotovorum in the greenhouse showed the superiority of the interaction treatments between more than one factor in reducing the percentage of infection to 0.00% where the treatment of Pcc + nano-magnesium oxide + goldstone + bltanol + Th showed a high efficiency in increasing the activity rates of the peroxidase enzyme, the total phenols accumulation, fresh and dry weight of shoot, number and weight of marketable tubers, at ( 41.02, 243.78, 50.09, 937.67, 88.67, 9.00, 974.08%), respectively, and with a significant difference compared (0.05)to the wounded and unwounded control treatment.