Barley amino acid transporters gene expression along leaf life-time is modulated by S starvation

CINTIA G. VELIZ; IRMA N. ROBERTS; CARLA CAPUTO

Foz de Iguazu

Congreso; 11th International Congress of Plant Molecular Biology; 2015

International Society for Plant Molecular Biology

In cereals a greatproportion of the nitrogen (N) required for the developing grains is guaranteedby amino acids remobilization, a process depending on amino acid transporters(AATs) proteins. Over the past decade, sulphur (S) availability hasbeen decreasing in several areas affecting both crops yield and grain storageproteins profile. Informationabout regulation of AATs expression is scarce and to date there are no reportson how this expression is affected by S deficiency. Here, we analyzedthe expression pattern of six barley AATs genes as affected by natural senescenceand by S starvation. Barleyplants were supplied with 1.2 mM S-SO4 till leaf n°3emerged and then, two treatments were established: control plants, maintainedin the same growing conditions, and S-starved plants, supplied with 1.25 mM S-SO4. Samples of leaf nº3were collected at 0, 3, 7, and 14 days after full expansion for qRT-PCR analysis. In control plants, theexpression levels of HvAAP2 and HvAAP4 decreased, HvAAP7 and HvProT1 increased and HvAAP6 and HvLHT2 kept constant along time. On the other hand, S starvation generated adiminution in the expression of HvAAP4, HvAAP6, HvAAP7 and HvProT1 but did not affect HvAAP2 and HvLHT2 gene expression compared to control plants. Our results suggestdifferential roles of these AATs during the life-time of the leaf under naturalsenescence and demonstrate down-regulation of its gene expression under Sstarvation, highlighting the impact of limiting S availability on N compoundsremobilization during plant senescence.