MOTT HAVEN — Critics are accusing Bronx Borough President Ruben Diaz Jr. of political retribution after he declined to reappoint a community board member who loudly opposed a major Borough Hall-backed project — FreshDirect’s subsidized move to The Bronx.

Mychal Johnson received an email Thursday with a copy of a brief form letter informing him of Diaz’s decision not to reappoint him to Community Board 1, where he has served since 2005.

Johnson is also a member of South Bronx Unite, a local group that has assailed the nearly $130 million proposed FreshDirect subsidy package as a taxpayer giveaway to a company that would send hundreds of trucks rumbling through an already-polluted neighborhood.

This is Diaz’s first opportunity to appoint board members since FreshDirect’s planned relocation was announced last year, sparking a swift local backlash.

Johnson was the only CB1 member not to be reappointed, Diaz’s office said.

Johnson and his supporters blasted Diaz's decision as pure political retaliation.

South Bronx Unite member Ed García Conde called Diaz a “coward” in a blog post and blasted his decision as a “dirty” and “disgusting” effort to stifle his opposition.

“We will NOT be silenced, Ruben Diaz, Jr,” he wrote.

Johnson, a Mott Haven resident and real-estate agent active in many local causes, worried that the move could have a chilling effect on other board members.

“It leads to a temperament of, 'I need to get along and not rock the boat, because if I rock the boat, there will be some retribution,'” he said. “And that’s not what we do in democracies.”

John DeSio, the borough president’s spokesman, said Diaz consulted with city council members during a “long internal process” before deciding upon board members.

“In the end, we make the selections based on how we believe people will represent both our office and their respective communities," DeSio said. "This office’s community board selections have been inclusive and reflective of the areas they serve.”

He would not comment directly on Johnson’s case.

Diaz has been a high-profile proponent of FreshDirect’s planned move from Long Island City to Port Morris, asserting that it will bring much-needed jobs and healthy food to the borough.

His office, including its economic arm, contributed $4.5 million in grants and loans to the public subsidy package.

“I welcome FreshDirect to The Bronx with open arms,” Diaz said when the proposed subsidy deal was made public in February 2012.

Meanwhile, Johnson has helped spearhead the opposition to the plan, claiming that it will exacerbate already-high asthma rates in the area and block access to the waterfront.

He has participated in FreshDirect protests and boycotts and is a petitioner in a lawsuit to block the company from building its new headquarters.

He declined to attend a private meeting between Diaz and FreshDirect opponents, both sides said, saying the discussion should be public.

And he proposed a resolution in the community board last year to condemn the way the FreshDirect deal was crafted, which Johnson said shut out the public.

More recently, he helped ensure that parts of the South Bronx waterfront, including the area where FreshDirect hopes to build its new facility, were included on a state list of proposed conservation sites.

Diaz’s office objected to the waterfront’s inclusion on that list.

The Rev. Ruben Austria, another Mott Haven resident and FreshDirect opponent, said Diaz’s decision appeared to be a cynical attempt to undermine Johnson, who he said represents “the future leadership of The Bronx.”

“This move is one of the last grasps of the establishment to hold onto its power,” Austria said. “But things are going to change in the years ahead.”