GraphTweets

# load twitteR to get tweets
library(twitteR)
token <- setup_twitter_oauth(consumer_key, consumer_secret, 
                             access_token=NULL, access_secret=NULL)
tweets <- searchTwitter("rstats", n = 200)
tweets <- twListToDF(tweets)

library(graphTweets)

edges <- getEdges(data = tweets, tweets = "text", source = "screenName")
nodes <- getNodes(edges)

# plot
g <- igraph::graph.data.frame(edges, directed=TRUE, vertices = nodes)

plot(g)