Artículos de revistas
Stress gene expression analysis in a tolerant maize landrace in response to combined salt and boron stress
Fecha
2013Institución
Resumen
To understand the molecular stress response in maize plants under high salt and boron (B) stress, we
focused on the transcript accumulation of six stress-related genes in Lluteño maize, a sweet corn
landrace from the Lluta valley (northern Chile), tolerant to salt and B stress. Lluteño maize and a
maize hybrid B73 seedlings were exposed to 150 mM NaCl and 20 ppm B in nutrient solution for
120 hrs, then roots and leaves samples were collected and Na+ and B concentration were
determined. Transcript accumulation of three salt stress-related genes SOS1, NHX2 and HKT1 and
three B stress-related genes BOR1, BOR2 and PIP1;2 were determined in roots and leaves of
Lluteño maize at 3 and 96 h after stress, using RT-PCR and real-time PCR. The results indicated
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that combined salt and B stress caused physiological parameter changes. The damage was more
severe in B73 than in Lluteño maize, confirming that this landrace behaves as a plant tolerant to
these stresses. Regulation of stress-related genes under combined stress was different than under
individual stresses. The ability of Lluteño maize to survive and thrive in soil with high salinity and
B concentration is probably based on decrease membrane water permeability preventing the salt and
B uptake from the roots through down-regulation of BOR1, BOR2 transporters and PIP1;2
aquaporin. The restriction of the B movement and accumulation in aerial parts through downregulation
of BOR1, BOR2 transporters. The increase water transport mediated by the up-regulation
of the PIP1;2 in leaves, allowing cellular water conservation, and the retrieval of Na+ from xylem
through up-regulation of HKT1;1 transporters in roots and leaves.
Key words: Salt tolerance, boron tolerance, Lluteño maize, SOS1, NHX2, HKT1;1, BOR1, BOR2,
PIP1;2.
Abbreviations: BOR_boric acid/borate transporters; HKT_high-affinity K+ transporter; KIRC_K+
inward-rectifying channel; KORC_K+ outward-rectifying channel; NHX1_Na+/H+ antiporter 1;
PIP_Plasma membrane intrinsic protein; SOS1_salt overly sensitive 1.