Many cultivated and wild grass species are hosts to mutualistic fungal endophytes. These associations are ecologically and agronomically significant, yet little is known regarding the physiological aspects of the interaction. In the Poa amp/a/Acremonium typhinum interaction, a fungal serine proteinase, Atl, is surprisingly abundant and may constitute 1 to 2% of the total leaf-sheath protein. Sequence analysis of cDNA and genomic clones indicates that proteinase Atl is a member of the eukaryotic subtilisin-like protease family. It is homologous to proteases suspected to be virulence factors in fungal pathogens of insects, nematodes, and other fungi. Cel blot analysis of RNA extracted from infected leaf-sheath tissue indicates that the proteinase Atl transcript leve1 is extremely high. RNA gel blots and immunoblots of purified enzymes indicate that similar proteinases are produced by Epichloe festucae and Acremonium lolii, the fungal endophytes infecting Festuca rubra subsp. rubra and Lolium perenne, respectively. Fungal expression of proteinase Atl-like enzymes may be a general feature of endophyte infection.

An effective technique was developed to inoculate mature Chewings fescue [Festuca rubra L. subsp. fallax (Thuill) Nyman] and strong creeping red fescue (Festuca rubra L. subsp. rubra) tillers with fungal endophytes (Epichloe festucae Leuchtm., Schardl, & Siegel and Neotyphodium spp.). Six fine fescue genotypes were successfully inoculated with endophytes originating from fine fescues and Poa ampla Merr. Eleven percent of the tillers were successfully inoculated, and all inoculated plants transmitted the endophytes to their offspring. This set of inoculated plants, with various combinations of genotypes and endophyte strains, allowed us to compare the effects of different endophytes on one host, and one endophyte on several hosts. When evaluated in the field, the growth characteristics of these plants were dependent on endophyte and host genotype. Considerable interaction between the genotypes was seen. For example, one host inoculated with the Poa ampla endophyte showed enhanced performance, while another host inoculated with the same endophyte performed poorly.

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Zymomonas mobilis is being considered for the industrial production of ethyl alcohol. Expansion of its substrate range of glucose, fructose and sucrose could be advantageous, but genetic manipulation of Z. mobilis is restricted as it is resistant to transformation. We present a protocol using electroporation for high efficiency transformation of this bacterium. Optimal parameters included cooled cells (0-4 ° C), use of 10% glycerol as an osmotic support medium, a pulse in the 12 kV/cm range for 10 ms and outgrowth on GYx medium prior to selection. The routine efficiency achieved was greater than 1.0× 107/~tg DNA, a major increase over other transformation methods in which yields ranged from 100-2000/~g DNA.