Water Restriction Alters the Expression of Calcium Transporters in Eucalypt Roots

Abstract

Background and Aims Calcium (Ca) plays an important role to increase drought tolerance in plants. We evaluated the effect of water restriction and Ca supply on the expression of Ca transporters, on Ca acquisition, allocation and its effects in eucalypt responses to drought. Methods Drought-tolerant eucalyptus plants (Eucalyptus urophylla x Eucalyptus camaldulensis - clone VM01) were grown in a hydroponic system in the presence or absence of Ca and subjected or not to water restriction using polyethylene glycol. Ca concentration by plants, gas exchange, plant growth, and the expression of the ACA11 and MCA1 Ca transporters were evaluated. Results Water restriction increased the expression of ACA11 (vacuole Ca transporter) and decreased the expression of MCA1(endodermal Ca transporter), in eucalypt roots. Water restriction increased Ca content in plant roots and Ca supply ameliorated the negative effects of water stress. Conclusion Water restriction alters the expression of Ca transporters in eucalypt roots altering the Ca allocation pattern and improving root growth and water status. Although caution must be taken, our findings bring novel evidence of an important mechanism that favors survival of drought-tolerant woody plants under water deficit.