It's hard to say that this is a JSON object inside a JSON object. First you use bubble="{} to create the first JSON object, and then textStyle:{} to create the next JSON object inside bubble="{} .
Here is my code and screenshot,
# install.packages("googleVis", dependencies = TRUE) require(googleVis) Bubble <- gvisBubbleChart(Fruits, idvar="Fruit", xvar="Sales", yvar="Expenses", colorvar="Year", sizevar="Profit", options=list(hAxis='{minValue:75, maxValue:125}', width=500, height=300), bubble="{textStyle:{color: 'none', fontName: <global-font-name>, fontSize: <global-font-size>}}") plot(Bubble)

Eric Fail
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