Overexpression of the Arginine Decarboxylase Gene Improves Tolerance to Salt Stress in Lotus tenuis Plants

ESPASANDIN, FABIANA D.; CALZADILLA, PABLO I.; MAIALE, SANTIAGO J.; RUIZ, OSCAR A.; SANSBERRO, PEDRO A.

JOURNAL OF PLANT GROWTH REGULATION

SPRINGER

Año: 2018 p. 1 - 10

0721-7595

To analyse the putative effects of putrescine on the plant response to salinity, micropropagated Lotus tenuis plants from wild-type and transgenic lines harbouring the pRD29A::oat arginine decarboxylase (ADC, EC 4.1.1.19) construct were subjected to a gradual increase in salinity that was applied gradually by means of sodium chloride irrigation (from 0 to 0.3 mol L−1) every 5 days up to the maximum concentration. At the end of the experiment, the transgenic lines were healthier than the wild-type plants and displayed a smaller reduction in shoot biomass and a slight increase in root growth in response to stress. The overexpression of ADC increased osmotic adjustment (5.8-fold) via the release of proline. The salinity treatment doubled the potassium uptake by roots from transgenic ADC stressed plants with a concomitant decrease in the accumulation of sodium, balancing the Na+/K+ ratio. Analysis of gene expression, enzymatic activities and hormone metabolism suggests a crosstalk between polyamines and abscisic acid in response to salinity via modulation of the abscisic acid biosynthesis-related enzyme 9-cis-epoxycarotenoid dioxygenase (EC 1.13.11.51) at the transcriptional level.