Martha C Hawes

Research Interests

Martha Hawes, PhD, realizes plants of many species systematically shed thousands of healthy cells from each of their root tips daily. Because these cells provide a living interface between the root and the soil, scientists refer to them as root "border" cells. This seemingly wasteful release of living somatic cells into environment is unique among higher organisms, and its function is unknown. Dr. Hawes’ hypothesis is that border cells provide a selective advantage to the plant by releasing specific chemicals that regulate levels of root- associated microorganisms. Soil-borne bacteria and fungi comprise not only pathogens that can destroy roots but also beneficial organisms that are crucial for normal plant development, therefore regulating the balance of such microbial populations is crucial to survival. Border cells act as a reservoir of chemicals that can specifically attract or repel microorganisms, as well as activate microbial genes headed for root infection. Mutants of soil-borne microorganisms have been used to demonstrate that, in some cases, recognition of such chemicals from the cells is required for the establishment of root-microbe associations. Her lab has identified border cell- specific genes cell as well as genes that are expressed among separation of border cells from the root. These plant genes are being used to genetically engineer plants with specific alterations in the production of border cells, and in their biological properties. These transgenic plants can be used test the hypothesis that border cells control the susceptibility of plants to infection by symbiotic and pathogenic bacteria and fungi.