Vital amines

Image: Wikimedia Commons.

Image: Wikimedia Commons.

Notwithstanding plants’ rightly applauded self-sufficiency, and remark­able life-sustaining syn­thetic abil­it­ies using basic inor­ganic ingredi­ents, some plant-like organ­isms need a little extra help in the form of organic com­pounds. Such organ­isms are known as auxo­trophs and a com­mon require­ment is for cer­tain vit­am­ins (those ‘vital amines’ of days gone by) in the case of cer­tain algae. The good news is that vit­am­ins such as B12 are provided by bac­teria, which the algae hap­pily ‘appro­pri­ate’. The bad news is that work by Sergio Sañudo-Wilhelmy et al. reveals that coastal waters of large areas of the east­ern Pacific Ocean are vitamin-deficient. Which is really bad news because the algae depend­ent upon such external sources of vit­am­ins are major play­ers on the world stage, both in terms of their primary pro­duc­tion – hence knock-on effects on the eco­sys­tems they would oth­er­wise sup­port – and their being sig­ni­fic­ant pro­du­cers of the oxy­gen we rely on for life. But, the – poten­tial (let’s be sci­en­tific­ally cau­tious about this…) – good news is that Erin Bertrand and col­leagues have iden­ti­fied a ‘cobal­amin acquis­i­tion pro­tein’ in diat­oms. So? Well, cobal­amin is an altern­at­ive name for cobalt-containing Vitamin B12, which appears to be required by those uni­cel­lu­lar algae (which are par­tic­u­larly abund­ant in the oceans and which are reputedly respons­ible for approx­im­ately 40% of mar­ine primary pro­ductiv­ity). This so-called ‘B12 claw’ is loc­ated in the cell wall and binds to B12, help­ing it to be taken up into the cell. Now here’s the really import­ant bit: when external B12 sup­plies are scarce more of the cobal­amin acquis­i­tion pro­tein is made. So, all that’s neces­sary is to engin­eer the gene for this pro­tein into algae in vitamin-deficient areas of the Pacific (and else­where) and the defi­ciency is over­come. Simple! Not quite… Sergio Sañudo-Wilhelmy et al. found mul­tiple vit­amin defi­ciency… Hmmm, claws for thought?

PS. I know you’re won­der­ing (or should be!), so to put your col­lect­ive minds at rest: higher plants neither make nor need vit­amin B12 because their ver­sion of the enzyme for which this is oth­er­wise a co-factor – methion­ine syn­thase – is cobalamin-independent.

Nigel Chaffey. ORCID 0000-0002-4231-9082

Nigel is a botanist and full-time academic at Bath Spa University (Bath, near Bristol, UK). As News Editor for the Annals of Botany he contributes the monthly Plant Cuttings column to that august international botanical organ. His main goal is to inform (hopefully, in an educational, and entertaining way...) about plants and plant-people interactions.