The phrase "a main supporter of" is correct and usable in written English.
It can be used to describe someone who plays a significant role in supporting a cause, organization, or individual.
Example: "She has always been a main supporter of environmental conservation efforts in her community."
Alternatives: "a key advocate for" or "a primary backer of".
Mr. Churkin, whose government is a main supporter of the Syrian government in the conflict and a strong critic of the armed rebels, urged the captors to release the peacekeepers immediately.
The detention of the peacekeepers came less than a week after Croatia announced it was withdrawing its soldiers from the Golan force, following reports that Croatia was selling weapons funneled to Syrian rebels by Saudi Arabia, a main supporter of the insurgency.
"I was walking up to that office and I was thinking, 'I don't have to do this.'" Hoberman, who has a young son and whose husband is a stay-at-home dad, is the main supporter of her family.
The second main supporter of the Assad regime is Iran--a country that have maintained a fairly unwavering relationship with Russia.
Cause of Action, a government watchdog group in Washington, quickly became the main supporter of the Lunnys' lawsuit to reverse the interior secretary's decision.
The main supporter of the Web site is the Smith-Richardson Foundation, a private group in Westport, Conn., that specializes in issues of national security.
Edwin had been the main supporter of Paulinus' mission, and with his death, a pagan backlash set in.
"We're looking at a lot of people that are the sole supporter for the family or main supporter of their family.
The N.I.H., the federal government's main supporter of biomedical research, announced that most of the chimpanzees it owns or supports — about 310 in all — will be retired in the next several years and moved to sanctuaries from which they cannot be recalled for research.
The National Institutes of Health, the main supporter of biomedical research at universities and medical schools, has an annual budget of more than $29 billion.
Target is the main supporter of the Brooklyn Academy of Music's community programs, including its annual Halloween extravaganza and the BAMkids Film Festival.
