Effect of temperature and inoculums level on development of soft rot of potato caused by Erwinia carotovora subsp. carotovora and their molecular detection through poymearse chain reaction

Abstract

Erwinia carotovora ssp. carotovora (Jones) (Bergey et al., 1939) (now known as Pectobacterium carotovorum subsp. carotovorum) are the causal agents of soft rot of potato. These diseases represent a serious threat to potato production and post harvest losses during storage in warm and temperate climates. The study on effect of different inoculums levels and temperature reveal that maximum rotting i.e. 83.33 % was recorded at 35 oC followed by 45% at 28 oC and 26.67% at 21 oC temperature at 108 cfu/ml inoculums level. The sensitive and early detection of soft rot pathogen, E. carotovora ssp. carotovora is key for the avoiding the occurrence of diseases in the field and rotting of tubers in storage. In present study, PCR protocol was developed for the detection of E. carotovora ssp. carotovora from potato tubers. A set of Oligos targeting the pectate lyase gene of E. carotovora ssp. carotovora amplified the 418 bp fragment. The sets were able to detect the E. carotovora ssp. carotovora upto 1.0 ng of genomic DNA and assay on CFU detection, allowed detection up to 103 cfu/ml of E. carotovora ssp. carotovora by PCR. So, detection by PCR methods offers sensitive, specific, reliable and fast detection of soft rot bacterial pathogens from potato tubers. Thus offers a gain in time and materials thereby emphasizes its importance in large-scale detection processes such as pathogen-free seed certification.