DELLAs contribute to set the response of Arabidopsis thaliana plants to conditions of potassium deprivation

OLIFERUK S; RODENAS R; PEREZ A; MARTINEZ V; RUBIO F; SANTA MARIA G.E.

JOURNAL OF PLANT GROWTH REGULATION

SPRINGER

Lugar: Berlin; Año: 2017

0721-7595

DELLAs  proteins  play  a  major  role  in  the  modulation  of  plant  responses  to  fluctuations  in environmental  conditions.  In  this  work  we  examined  to  what  extent  Arabidopsis  thaliana  plants lacking DELLAs activity (5xdella mutant) or carrying an altered function allele of one of the DELLAs coding  genes  (gai-1  mutant),  display  differential  responses,  in  terms  of growth  and  shoot  elemental composition,  relative  to  WT  plants  when  deprived  of  potassium  (K).  Studies  with  plants  grown  in hydroponic media unveiled that the shoot mineral composition of gai-1 constitutively differs from that of WT and 5xdella plants. Tolerance to K-deprivation, as estimated by the relative decline of biomass accumulation,  followed  the  order  gai-1>WT>5xdella.  In  turn,  the  degree  of  responsiveness  of  the shoot  composition  to  the  stress  condition  followed  the  order  5xdella>WT>gai-1,  suggesting  a correspondence  between  the  degree  of  injury  and  changes  in  the  elemental  composition.  Internal efficiency  of  K  utilization  was  maximized  in  WT  relative  to  5xdella  plants.  Interestingly,  the acquisition  of  K  was  severely  impaired  in  gai-1  plants  well  supplied,  or  deprived  of,  K. Complementary studies indicated that influx  and root-to-shoot transport of Rubidium, a  K-analogue, were  reduced  in  those  plants.  Furthermore,  evidence  obtained  supports  the  view  that  the  effect  of altered DELLAs derives, at least partially, from controlling the accumulation of transcripts coding for the AtHAK5 transporter. These results, together with the observation that K-deprivation promotes the accumulation  of  a  DELLA  protein  (RGA)  fused  to  GFP  in  root  cells,  suggest  a  pivotal  role  of DELLAs in key plant responses to K-deprivation.