Can i file for defamation?

I am a senior professor with a UGC registered private university in Bangalore. Some months back I had submitted a proposal for a research grant to a Govt. of India scientific organization, in response to their public call. Now a few days back, some scientist from the organization wrote to me saying the proposal was 'poorly written' and some so- called expert committee had not found anything worthwhile in it. On the contrary, I fully stand by the worth of my proposal that has been jointly authored by me and two other distinguished faculty in associate sister institutions. The scientist's response is I believe, arrogant and contemptuous, with a sinister intent to prevent the grant from being awarded to us, being a private university. While it is not quickly possible to establish the malefic intent, I wish to file a defamation case against the scientist for his contemptuous unjustifiable remarks that I can nevertheless defend against. Would be grateful to have expert legal opinion on this.