Physiological and genetic analysis of tomato from two cultivars differing in potassium deficiency resistance

Potassium (K) is one of the essential nutrients for tomato. Potassium deficiency will limit tomato growth and yield. So improving the low-K+ (LK) resistance of tomato seems important. Two tomato cultivars (JZ18 and JZ34) differing in LK resistance were obtained to analyze the plant demonstration difference under LK treatment. According to the results, JZ34 showed lower accumulation of ROS, less membrane damage and higher antioxidant enzyme activity after LK treatment. Besides, JZ34 also keeps higher K+/Na+ content, higher Ca2+ and Mg2+ content than JZ18 in both shoots and roots. Our genetic analysis revealed that the two additive-dominance-epistasis major genes plus additive-dominance polygene genetic model (E-1) was the optimum model associated with LK resistance based on root trait. The major QTL intervals were finally obtained by the bulked segregant sequencing (BSA-seq) analysis, which were 2.38 Mb at the end of chromosome 4 and 1.38 Mb at the chromosome 6. This is consistent with the analysis of the genetic model. A total of 8 genes were selected in the two candidate regions, which exhibited close related to ion and antioxidant signaling. These findings provided the inheritance pattern and foundation for further molecular mechanisms study of tomato LK resistance.