[Analysis of the heterogeneity of avirulent -mutant by high performance ion-exchange chromatography].

The heterogeneity of avirulent -mutant, virulent wildtype strain FJAT-91 and spontaneous avirulent strain FJAT-1458 were compared and analyzed by using high performance ion-exchange chromatography (HPIEC). Their colony and cell morphologies were observed, and the contents of their extracellular polysaccharides (EPS) were determined. The results showed that the colony and cell morphologies of FJAT-91 were different from the original strain FJAT-91, but were similar to the spontaneous avirulent strain FJAT-1458. The EPS content of FJAT-91 was (12.64±1.46) μg/mL, which was much lower than FJAT-91 with (30.49±2.97) μg/mL. The strain FJAT-91 were separated into single peak of P at the retention time of 6.04 min, and FJAT-91 had two peaks (P and P) at the retention times of 0.59 min and 4.62 min, respectively. FJAT-1458 formed single peak of P at the retention time of 0.59 min. Then, the bacteria eluents from different chromatographic peaks were collected and their pathogenicities were detected with bioassay test using potted tomatoes in the greenhouse. The results showed that the tomato plants began to wilt 4 d after inoculation of strain FJAT-91-P eluted from P, and the disease incidence reached 100% at 10 d post inoculation. The strain FJAT-91 -P eluted from P caused tomato plants wilting 9 d after inoculation, and the disease incidence reached 100% at 20 d. During 20 d of observation, none of tomato plants caused wilting while inoculation with FJAT-1458-P and FJAT-91 -P eluted from P of FJAT-1458 and FJAT-91 , respectively. In this paper, the morphologies, EPS contents and chromatographic behaviors of FJAT-91, FJAT-91 and FJAT-1458 were compared, which would provide theoretical basis for using FJAT-91 to control bacterial wilt disease.