The Path of Carbon in Photosynthesis – XXVIII – Response of Plants to Polyalkylglucopyranose and Polyacylglucopyranose

A series of discoveries began 63 years ago through the collaboration of Melvin Calvin and Andrew Benson 1948. Paving the path (Benson 2002a) has since included the publications that have described the initial products of carbon fixation, from phosphoglycerate onward. From its inception, the program has followed a design that has been based on far-reaching interdisciplinary discourse, quoting the philosophy of Alexander Graham Bell, that, "Great discoveries and improvements invariably involve the cooperation of many minds." For example, investigations three decades ago by Wolf, Nonomura & Bassham 1985, established characteristics of the alga, “Showa,” that accumulated the highest in vitro concentrations of hydrocarbons, 40% botryococcenes; from which gasoline and aviation fuels may be derived by catalytic hydrocracking in a conventional petroleum refinery. Studies of algal metabolism were as critical to the development of concepts of the Prize from 1948 through 1961, as they are today--special reference given to the lollipop (Nobelprize, 2011), a flat panel glass chamber that was designed by Benson and built by Harry Powell for controlled culture of Chlorella to track radiolabeled carbon metabolism in the laboratory --and thereby, paths converged, as Nonomura & Benson 1992 developed experimental methods for the feeding of single-carbon (C1) fragments to “Showa.” That led to foliar delivery into angiosperms of up to 15 M C1 formulations supplemented with normally phytotoxic levels of ammoniacal nitrogen. When these applications were undertaken in sunlit fields, adjacent controls wilted by mid-afternoon, but rows treated with C1 formulations remained fully turgid, showing no signs of wilt. Moreover, Benson & Nonomura 1992 discovered that treatments with these C1 formulations inhibited glycolate formation, confirming their observations of long durations of reduced photorespiration. In addition to replicating increased yields, Ligocka et al. 2003 discovered corresponding increases of nitrate reductase and alkaline phosphatase by C1 formulations. In the meantime, Gout et al. 2000 followed metabolism of the C1 formulations by NMR to the identification of methyl--Dglucopyranoside; be that the case, little is known about glycosylation although it is a natural process in the metabolism of C1 fragments. Thus, in our programs of experimental biology, we investigated responses of plants to substituted glycopyranosides (Benson, 2002a); and we recently showed that not only do substituted glycopyranosides improve productivity, they are transported in plants and metabolized (Benson et al., 2009; Biel et al., 2010;