Natural Variation for Responsiveness to flg22, flgII-28, and csp22 and Pseudomonas syringae pv. tomato in Heirloom Tomatoes
Figure 4
A genetic approach to characterize csp22 responsiveness.
Leaf discs from RG-PtoS and LA2109 were treated with 100 nM flg22 (A) or 1 µM csp22 (B) and ROS production measured every 2 minutes over the time course shown. The curves are the average of 2 plants from independent experiments, and are representative of the trend observed with several other plants. C) To identify csp22 low-responding F2 plants, the sum of the ROS curves (as shown in A) was determined for flg22 and csp22, and the ratio of csp22-to-flg22 response was determined (csp22/flg22). The numbers at the bottom indicate individual F2 plants. A threshold value of 0.25 was set as the upper limit for defining low responsiveness. Of 147 F2 plants tested, 41 were classified as low csp22 responders. A chi-square test for fitting to a 3∶1 was performed and Χ2 = 0.58.