p. adjust for multiple columns in the same dataframe in R

I have a dataframe with hundreds of p values I want to compute FDR significance for.

My dataframe:

Trait p-value1 p-value2 p-value3 pvalue4
1 0.5 0.01 0.1 0.12
2 0.1 0.9 0.4 0.32
3 0.2 0.45 0.34 0.45
4 0.2 0.02 0.22 0.11

I do it separately for each column with the following script (example on p-value1):

fdr <- p.adjust (p-value1, method = "fdr", n = length(p-value1)) 

How can I do it for all columns at the same time?