Submitted to: Plant Physiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 13, 1999
Publication Date: N/A
Interpretive Summary: When exposed to environmental stress, such as temperature extremes, poisons, or attack by pathogens, plant cells respond with a large-scale shift in behavior. Normal, "house-keeping" activities are stopped and a small number of stress-related functions are turned on. Included in the stress response are the production of specific chemicals. It has long been assumed that these stress chemicals were able to function individually. A variety of methods were employed to identify some of the stress chemicals produced by corn, and it was shown that many of the chemicals function together in a complex mixture rather than as individuals. This information will be important to researchers in their attempts to increase agricultural productivity by altering the control of plant cell respiration and to other plant scientists who will try to design more efficient crop plants through either classical breeding or biotechnology.
Technical Abstract: A high molecular weight chaperone heterocomplex (CCH) was isolated from a cytosol fraction prepared from cultured maize (Zea mays L. Inbred A636) endosperm cells. Three species of CCH could be partially resolved by rate-zonal sedimentation. The protein composition of the CCH was probed using mono-specific antibodies, identifying homologues of the Stress70, Stress90, YdJ1 and Sti1p/p60 proteins. The CCH additionally contained prolyl-isomerases of both the cyclophilin A and FKBP families. Furthermore, the small calcium-binding regulatory protein, calmodulin, was associated with one species of the complex. Thus, while there are some distinctions, plant cells contain a CCH with protein components similar to those previously described as participating in the maturation of hormone receptors and protein kinases in mammalian and fungal cells.