IRON ACQUISITION IN LOTUS CROPS SUBJECTED TO ALKALINE STRESS: RESPONSE TO INOCULATION WITH Pantoea eucalypti M91

MARÍA PAULA CAMPESTRE; NAZARENO CASTAGNO; CRISTIAN JAVIER ANTONELLI; VANINA MAGUIRE; ANA PEREA GARCÍA; FRANCISCO ESCARAY; OSCAR ADOLFO RUIZ

Buenos Aires

Congreso; REUNIÓN CONJUNTA DE SOCIEDADES DE BIOCIENCIAS (LIII REUNIÓN ANUAL DE LA SOCIEDAD ARGENTINA DE INVESTIGACIÓN BIOQUÍMICA Y BIOLOGÍA MOLECULAR (SAIB)); 2017

SOCIEDADES DE BIOCIENCIAS

Alkaline soils are characterized by low availability of essential nutrients, including iron (Fe), causing Fechlorosis and therefore affectingplant growth. In addition, soil microorganisms, through production of siderophores, may play an important role capturing this element under limited conditions. Here, we aimed to study the response ofL. tenuis(Lt) and L. corniculatus(Lc) and an interspecific hybrid LtxLc obtained in our laboratory to alkaline treatment (10mM NaHCO3) and inoculation with P. eucalypti M91 (PM91), a plant growth-promoting bacterial strain capable of producing siderophoresat high pH.At first, we observed that alkalinity affected shoot growth of Lc (p=0.0049) and developed chlorosis in their leaves. Interestingly, when inoculated with PM91,Lc exhibited an increase in shoot growth (p=0.039). On the other hand, no detrimentaleffect was seen in growth of shoots and roots of Lt and LtxLcwhen exposed to alkalinity,but no effect of inoculation was observed either. Moreover, the Fe2+ content in shoots of Lc and LtxLc when cultivated under alkaline conditions was lower than controls (p≤0.01), but when inoculated, the Fe2+ content in shoots increased in all cases obtaining even greater values than the ones reached at controls. In addition, all species increased their Fe2+root contents under alkalinity, comparedto controls. Furthermore, the Fe2+ accumulation was higher in the roots of alkaline treated Lc (2-fold) than in the other species. These results, together with the chlorosisobserved in Lc grown under alkalinity, reveal a flaw in Fe2+ translocation from roots to shoots. However, inoculation improved the Fe2+ balance for this species, resulting in high endogenous Fe2+ content in the shoots, with accompanying re-greening in young leaves. These findings suggest that particularly, Lc is the species more affected to alkaline stress; however inoculation with PM91 generates an increase in the Fe2+ content of the three studied accessions.Keywords:Alkalinity, Lotus spp., Fe, endophytic bacteria.