Highlighting some points in a serie with hundred of points plotted as a line.

I have submitted to a journal colored figures containing some several curves with hundreds of points. The editor asked me to identify the curves so that the plots can be distinguished even in black and white printing. For this, I would like to highlight one point over 50 or 100 while keeping in the legend the line+marker sign. This is possible in software like Origin but I would like to program it on Matlab, where all my data are, as results of my calculations. Could you help me ?