Unfortunately, no. It is not possible to convert R code automagically to Matlab code.
What you can do is call the R code from Matlab (e.g. using a file for data sharing and calling R through the system command). There is something available on the FEX (MATLAB R-link), but it is fairly old and seems to only work on Windows.
Otherwise you will have to replicate the functionality of the R function. Not every function has a 1-to-1 equivalent, which makes sense as R and Matlab are different languages. The languages are similar, so going line by line isn't a bad first step.
