Making Salt-Tolerant Plants

Abstract

Plant Science![Figure][1] CREDIT: MOLLER ET AL., PLANT CELL 21 , 10.1105/TPC.108.064568 (2009) Crops grown in salty soils yield less. Soils may be too salty naturally, as expanding land use presses hectares of marginal quality into agricultural service, and reasonable-quality lands can become too salty because of the effects of long-term irrigation. Plants respond to an excess salt in various ways: Some transport salt from the roots to the aboveground shoots; some sequester excess salt into vacuoles; and some are able to exclude excess Na+ from the shoot tissues. As the first point of contact between the plant and salty soils, how the roots balance Na+ influx and efflux determines how much Na+ the plant has to deal with. Moller et al. have manipulated Na+ transport in the whole plant or only in the roots (cross section at left) and assessed the outcome in Arabidopsis . When the Na+ transporter is overexpressed constitutively, the plants are, if anything, more sensitive to salt. In contrast, when the transporter is overexpressed specifically in the root stele tissue, which includes the vascular system that feeds the shoots, the plants become more salt-tolerant. In this case, less Na+ is transported to the shoots, even though the amount of Na+ taken up from soil into root remains unchanged. Plant Cell 21 , 10.1105/tpc.108.064568 (2009). [1]: pending:yes