Mary Jeanette Whitehurst Bryant, 49, who retired last year as a microbiologist at the Armed Forces Institute of Pathology at Walter Reed Army Medical Center, died of cancer Wednesday at the Washington Hospital Center.

Mrs. Bryant was born in Durham, N.C., and earned bachelor's and master's degrees in biology at North Carolina Central University. From 1960 to 1962, she worked for the Veterans Administration in Durham.

She then moved to Washington and was assigned by the VA to the Armed Forces Institute of Pathology. She retired for reasons of health.

Mrs. Bryant was a member of the American Institute of Parliamentarians and a member and former president of the Federally Employed Women, the Capital Business and Professional Women's Club and the Walter Reed branch of the International Toastmistress Club.

Survivors include two daughters, L. Yvette Bryant Loewen of Washington, and Kathlyn G. Bryant of Lodi, N.J.; one son, James R., of Durham; one brother, John E. Whitehurst of Riverside, Calif.; three half-brothers, Vernet Johnson and Dorothy and Audrey Brown, all of Washington; Marion Russell of Lawrenceville, Va., and Jaris Evans of Portsmouth, and four grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the American Cancer Society.