Preliminary data on the presence of an alternate vanadium nitrogenase in a culturable cyanobiont of R. Brown: Implications on Chronic Kidney Disease of an unknown etiology (CKDu).

In a recent paper titled "How a taxonomically-ambiguous cyanobiont and vanadate assist in the phytoremediation of cadmium by : implications for CKDu" (Atugoda et al., 2018) [1] it was shown by us, that plant health and phytoremediation capacities, of R. Brown, were elevated in the presence of vanadate, a vanadium containing ion. This highlighted a possibility, that either the major or minor cyanobionts of , could possess a vanadium dependent nitrogenase enzyme, as an alternate nitrogenase, in addition to the molybdenum counterpart. In this data article, we report the isolation of a minor cyanobiont which we name as We grew , exclusively in N-free media, with only molybdenum (Mo+ V-), with only vanadium (V+ Mo-) and with neither (negative control), to find out the growth patterns in the relevant media. While grew as green colored consistencies, increasing gradually in turbidity, for 4 weeks in culture, both, in the presence of molybdenum (Mo+ V-), as well as vanadium (V+ Mo-), the negative control, showed no, or very little growth. This alludes to the presence of dual nitrogenases in . An attempt was also made by us to unravel the genes, responsible for the V-nitrogenase. However, it was not possible to PCR amplify the genes, from both, the unculturable major (using total DNA from the Azolla- symbiosis) and minor (DNA directly from the cultured ) cyanobionts. This is the first time, to our knowledge, that an endosymbiotic cyanobacterium inside a plant compartment, has been shown to contain two possible nitrogenase systems.