Mutant Rht-1 altered function alleles influence the response of wheat plants to K+ deprivation

MORICONI, JORGE I.; BUET, AGUSTINA; SIMONTACCHI, MARCELA; SANTA-MARIA, GUILLERMO E.

Congreso; XLVII Reunión Anual - Sociedad Argentina de Investigación en Bioquímica y Biología Molecular; 2011

Potassium (K+) is an essential nutrient for plant growth and development. The pathway by which higher plants restrict their growth under K+ deprivation conditions is not well understood. In bread wheat (Triticum aestivum), DELLA proteins are encoded by the Rht-1B and Rht-1D genes: the allelic variants Rht-1Ba/Rht-1Da, determine a wild type (WT) phenotype, while the presence of the Rht-B1b /Rht-D1b altered function alleles determine a dwarf phenotype (DD). In this work, we evaluated the role of those alleles during the acclimation of plants to K+ deprivation by using two set of near isogenic lines (NILs) of Maringa and April Bearded cultivars. Chlorophyll content of WT NILs sharply declined after a 16 d period of K+-deprivationm while in DD NILs chlorophyll content only marginally declined. This difference was companied in Maringa, but not in April Bearded, by a positive impact on plant growth. In turn, no differences between WT and DD NILs were observed for indicators of oxidative damage oxidative. However, DD NILs of both cultivars exhibited an increased induction of ascorbate peroxidase and superoxide dismutase activities, as well as changes in the ionic composition (K+, Na+, Ca2+) of plants grown without K+-addition. Our data indicate that the acclimation response to K+-starvation is strongly influenced by the presence of altered function alleles.