Biological characteristics and metabolic phenotypes of different anastomosis groups ofRhizoctonia solanistrains

Abstract

AbstractRhizoctonia solaniis an important plant pathogen worldwide, and causes serious target spot disease in tobacco in the last five years. This research studied the biological characteristics of four different anastomosis groups (R. solaniAG-3,R. solaniAG-5,R. solaniAG-6,R. solaniAG-1-IB) ofR. solanifrom tobacco, and analyzed the metabolic phenotype differences of these strains using metabolic phenotype technology. The results showed that the suitable temperature for mycelial growth of four anastomosis group strains were all from 20 to 30 °C, and for sclerotia formation were from 20 to 25 °C. Under different lighting conditions,R. solaniAG-6 strains produced the most sclerotium, followed byR. solaniAG-3,R. solaniAG-5 andR. solaniAG-1-IB. All strains had strong oligotrophic survivability, and can grow on water agar medium without any nitrutions. They exhibited three types of sclerotia distribution form, including dispersed type (R. solaniAG-5 andR. solaniAG-6), peripheral type (R. solaniAG-1-IB), and central type (R. solaniAG-3). They all presented different pathogenicities in tobacco leaves, with the most virulent was noted byR. solaniAG-6, followed byR. solaniAG-5 and AG-1-IB, finally wasR. solaniAG-3.R. solaniAG-1-IB strains firstly present symbtom about inoculation. Metabolic fingerprints of four anastomosis groups were different to each other.R. solaniAG-3, AG-6, AG-5 and AG-1-IB strains efficiently metabolized 88, 94, 71 and 92 carbon substrates, respectively. Nitrogen substrates of amino acids and peptides were the significant utilization patterns forR. solaniAG-3.R. solaniAG-3 and AG-6 showed a large range of adaptabilities and were still able to metabolize substrates in the presence of the osmolytes, including up to 8% sodium lactate. Four anastomosis groups all showed active metabolism in environments with pH values from 4 to 6 and exhibited decarboxylase activities.One-sentence summaryRhizoctonia solanistrains from different anastomosis groups have a different adaptability to habitats.