A famine cri­sis is loom­ing. Stephen Long’s work aims to feed the masses by su­per­charg­ing the plants we eat

BBC Earth (Asia) - - Science -

“The UN Food and Agri­cul­ture Or­ga­ni­za­tion says that we’re go­ing to need 70 per cent more food by 2050. With cur­rent rates of crop im­prove­ment we’re not go­ing to get there”

In the mid­dle of the 20th Cen­tury, many parts of the world were on the brink of famine. A grow­ing global pop­u­la­tion was butting up against the lim­its of food sup­ply, with dis­as­trous con­se­quences. But the lives of more than a bil­lion peo­ple were saved by a ‘Green Rev­o­lu­tion’ – the spread of tech­niques like ir­ri­ga­tion, hy­bridised seeds, and hu­man-made fer­tilis­ers and pes­ti­cides from in­dus­tri­alised coun­tries to the de­vel­op­ing world.

To­day, we’re fac­ing a sim­i­lar cri­sis. “The UN Food and Agri­cul­ture Or­ga­ni­za­tion says that we’re go­ing to need 70 per cent more food by 2050, and with cur­rent rates of crop im­prove­ment we’re not go­ing to get there,” says Stephen Long, di­rec­tor of The RIPE Project, which aims to spur a sec­ond Green Rev­o­lu­tion by en­gi­neer­ing crops so that they’re able to pho­to­syn­the­sise more ef­fi­ciently.

“Pho­to­syn­the­sis is the process that con­verts sun­light en­ergy and car­bon diox­ide into the sub­stance of a plant, so it’s ba­si­cally the source, di­rectly or in­di­rectly, of all of our food. We know that in crop plants this process is not ac­tu­ally very ef­fi­cient, and we now un­der­stand enough about the process that we can start to in­ter­vene and ge­net­i­cally im­prove its ef­fi­ciency.”

His­tor­i­cally, pre­vail­ing wis­dom has al­ways been that pho­to­syn­the­sis couldn’t be made more ef­fi­cient. Af­ter all, why would evo­lu­tion have not op­ti­mised such an im­por­tant process? But Long points out that evo­lu­tion op­ti­mises for sur­vival and re­pro­duc­tion, not max­i­mum out­put of the seeds and fruits that hu­mans eat.

Mean­while, we’re liv­ing in a dif­fer­ent en­vi­ron­ment from the time of the first Green Rev­o­lu­tion. “A ma­jor mol­e­cule in­volved in pho­to­syn­the­sis is car­bon diox­ide, and in the last 50 years, through our ac­tiv­i­ties, we’ve in­creased the con­cen­tra­tion of car­bon diox­ide in the at­mos­phere by 25 per cent. That is a very short time for evo­lu­tion to adapt to a change,” says Long.

So, he and his team set to work prov­ing that it was pos­si­ble to boost the ef­fi­ciency of pho­to­syn­the­sis. With fund­ing from the Bill and Melinda Gates Foun­da­tion, they started tin­ker­ing with to­bacco – a plant that’s rel­a­tively easy to en­gi­neer. To be­gin with, his team transferred genes from Ara­bidop­sis thaliana, bet­ter known as thale cress, to the to­bacco plant in the hope of help­ing it shed heat en­ergy more ef­fi­ciently. When three vari­ants of these en­gi­neered plants were grown, their yields were 13.5 per cent, 19 per cent and 20 per cent greater than nor­mal to­bacco plants grown as a com­par­i­son. “Although we un­der­stand pho­to­syn­the­sis now in plants in great de­tail, it is a com­plex process. It’s over 160 dis­crete steps. The first part of the project was ac­tu­ally sim­u­lat­ing the whole thing on a com­puter. We could then try bil­lions of ma­nip­u­la­tions, math­e­mat­i­cally, to then see where might be the best places to in­ter­vene.”

What’s more, these im­pres­sive gains were achieved with min­i­mal in­creases in re­source costs. The en­gi­neered plants re­quired about 1 to 2 per cent more ni­tro­gen than the un­mod­i­fied plants, and no in­crease in wa­ter use. “That is re­ally the beauty of im­prov­ing pho­to­syn­thetic ef­fi­ciency,” says Long. “It’s not only the ef­fi­ciency with which they use light, but it’s also the ef­fi­ciency with which they use wa­ter and ni­tro­gen. So in most cases, we are get­ting more pro­duc­tiv­ity for the same amount of wa­ter, and min­i­mal in­creases in ni­tro­gen.”

The big ques­tion is whether these gains in to­bacco can be transferred to food crops, and there’s rea­son to be­lieve that they can. Pho­to­syn­the­sis works in the same way in to­bacco as it does in many food crops, and tests are planned to see if sim­i­lar mod­i­fi­ca­tions can de­liver in­creases in yields of staples like rice, cow­peas and cassava. The po­ten­tial is enor­mous, but the clock’s tick­ing. “Any in­no­va­tion we have to­day is go­ing to take about 20 years to be avail­able to farm­ers at the scale we need,” says Long. “So while 2050 might sound a long way off, in terms of im­prov­ing crop pro­duc­tiv­ity it’s quite close.”

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