Fig. 4

Histological characteristics of the roots of the mock and infected resistant and susceptible cultivars at the tillering stage (Z21) under transmission electron microscopy. a Vascular bundle cells and cortical parenchyma cells of the mock resistant cultivar. b Vascular bundle cells and cortical parenchyma cells of the infected resistant cultivar. c Vascular bundle cells and cortical parenchyma cells of the mock susceptible cultivar. d Vascular bundle cells and cortical parenchyma cells of the infected susceptible cultivar. e Root cell contents of the mock resistant cultivar. f Root cell contents of the infected resistant cultivar. g Root cell contents of the mock susceptible cultivar. h Root cell contents of the infected susceptible cultivar. i Root nucleus of the mock resistant cultivar. j Root nucleus of the infected resistant cultivar. k Root nucleus of the mock susceptible cultivar. l Root nucleus of the infected susceptible cultivar. The resistant cultivar was Mianyang 26/Yumai 47 and the susceptible cultivar was CU42. Black arrows in (a-d) indicate cortical parenchyma cells, red arrows in (a-d) indicate vascular bundle cells, black arrows in (e-h) indicate root cell contents, and black arrows in (i-l) indicate root nuclei (N: Nucleus; M: Mitochondrion; scale bar of (a-f) = 20 μm; scale bar of (g and h) =10 μm; scale bar of (i and j) =2 μm; scale bar of (k and l) =0.5 μm)